comparative effectiveness of core-needle and open surgical ... · routine breast cancer screening...

Background

Breast cancer is the second most commonmalignancy of women, with over 180,000new cases diagnosed each year in theUnited States. Survival rates depend on thestage of disease at diagnosis. Womendiagnosed with early stages of breastcancer have a 5-year survival rate near 100percent. However, early breast cancer isasymptomatic, and the only way to detect itis by population-wide screening programsthat include regular mammography andphysical examination.

Mammography uses x-rays to examine thebreast for calcifications, masses, or otherabnormal structures. Currently, mostprofessional organizations recommend thatall women 50 years of age and over receivea mammogram every 1 to 2 years. Manyprofessional organizations recommend thatroutine breast cancer screening beginearlier, at age 40, although x-raymammography screening is less effectivein younger women. Most experts believethat regular x-ray mammographicscreening of all women ages 50-70 canreduce mortality from breast cancer.

Comparative Effectiveness of Core-Needle and Open Surgical Biopsy for the Diagnosis

of Breast LesionsExecutive Summary

Effective Health Care Program

Effective Health Care Program

The Effective Health Care Programwas initiated in 2005 to provide validevidence about the comparativeeffectiveness of different medicalinterventions. The object is to helpconsumers, health care providers, andothers in making informed choicesamong treatment alternatives. Throughits Comparative Effectiveness Reviews,the program supports systematicappraisals of existing scientificevidence regarding treatments for high-priority health conditions. It alsopromotes and generates new scientificevidence by identifying gaps inexisting scientific evidence andsupporting new research. The programputs special emphasis on translatingfindings into a variety of usefulformats for different stakeholders,including consumers.

The full report and this summary areavailable at www.effectivehealthcare.

Comparative Effectiveness Review Number 19

Effective Health Care

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The American College of Radiology has created astandardized system for reporting the results ofmammography, the Breast Imaging Reporting and DataSystem (BI-RADS®). There are seven categories ofassessment and recommendation:

0 Need additional imaging evaluation and/or priormammograms for comparison.

1 Negative.

2 Benign finding.

3 Probably benign finding. Initial short-intervalfollowup suggested.

4 Suspicious abnormality. Biopsy should beconsidered.

5 Highly suggestive of malignancy. Appropriateaction should be taken.

6 Known biopsy-proven malignancy. Appropriateaction should be taken.

After identification of an abnormality on screeningmammography or physical examination, womentypically undergo additional imaging studies (diagnosticmammography, ultrasound, magnetic resonanceimaging [MRI]) and a physical examination. If thesestudies suggest the abnormality may be malignant,a biopsy of the suspicious area may be recommended.Biopsy material may be obtained by fine-needleaspiration, core-needle biopsy, or open surgicalprocedures.

Open surgical biopsy involves removing a sample oftissue from the suspicious area through a surgicalincision. To aid in location of a nonpalpable lesion, itmay be marked with a wire, dye, or carbon particlesusing an imaging method (mammography, ultrasound,MRI) to guide placement of the marker. The proceduremay be performed under general anesthesia, sedationplus local anesthesia, or local anesthesia only. Thesurgeon may attempt to remove the entire lesion duringthe biopsy procedure (excisional biopsy) if the lesion isfairly small. After the tissue sample is removed, theincision is closed with sutures.

Open surgical biopsy is the “gold standard” or“reference standard” method of evaluating a suspiciousbreast lesion because it is thought to be very accurate indiagnosing these lesions. While generally considered

safe, it is a surgical procedure that, like all surgeries,places the patient at risk of experiencing morbiditiesand, in rare cases, mortality. However, only 20 to 30percent of women who undergo breast biopsyprocedures are diagnosed with cancer. Exposing largenumbers of women who do not have cancer to invasivesurgical procedures may be considered an undesirablemedical practice. A less invasive method for evaluationof suspicious breast lesions would be preferable if itwere sufficiently accurate.

A core-needle biopsy is a procedure that involvesremoving small samples of breast tissue through ahollow core needle inserted through the skin. Basiccore-needle biopsy uses a special 11-, 14-, or 16-gaugeneedle (the smaller the gauge, the larger the diameter ofthe needle). The suspicious lesion may be located bypalpation or by imaging (stereotactic mammography,ultrasound, MRI). The procedure is usually performedunder local anesthesia. Multiple core-needle samplesmay be taken from the suspicious area.

A variant on core-needle biopsy is vacuum-assistedbiopsy. After locating the suspicious area by stereotacticmammography or ultrasound, the probe of the device isinserted into the suspicious area. The device usesvacuum suction to help remove tissue samples. Multiplesamples may be taken from the suspicious area withoutreinserting the needle.

The primary goal of initial biopsy of any abnormality isto diagnose the abnormality as benign or malignant.Generally, only malignant lesions require invasivefollowup procedures such as surgical excision or lymphnode evaluation. As discussed above, the majority ofwomen who are sent for breast biopsy do not havemalignant lesions and do not require followup surgery.Thus an accurate initial core-needle biopsy would inmost cases allow women to avoid any open surgicalprocedure. If the core-needle biopsy suggests the lesionis malignant, lymph node exploration and lesionexcision to clear margins could be performed during thefollow-on surgical procedure. Women who arediagnosed with malignant lesions by open surgicalbiopsy are often subject to an additional surgicalprocedure to ensure the lesion has been completelyremoved and, in some cases, for lymph node evaluation.Therefore, an accurate method of performing core-needle biopsies may enable many women to avoid

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surgery altogether and reduce the number of surgicalprocedures women with malignancies must undergo.

Medical indications—such as size and location of thelesion, imaging characteristics of the lesion, andlikelihood of eventual surgical excision—may direct thepreference of one type of breast biopsy procedure overanother. However, other factors—such as patientpreferences, access, and practice and referral patterns—also influence decisions about which procedure shouldbe performed.

The large number of possible methods of performingbreast biopsy can be bewildering to patients and healthcare providers alike. Which method should one choose?Is a particular method clearly superior, or does themethod of choice depend upon individual patientcharacteristics? We have performed a systematic reviewintended to evaluate the accuracy of different methodsof performing breast biopsy and to explore whatfactor(s) may impact the accuracy and possible harmsof different methods of performing breast biopsy.

Methods

The topic of this systematic review was nominated in apublic process. The Key Questions were developed by atechnical expert panel assembled by the ScientificResource Center for the Agency for HealthcareResearch and Quality (AHRQ). The medical literaturewas systematically searched for articles from December1990 through September 11, 2009, that addressed theKey Questions.

Medical personnel usually want to see the results of atleast one randomized controlled trial demonstrating thata medical procedure is safe, effective, and beneficial topatients before adopting the procedure into generalclinical practice. However, it is generally acknowledgedthat early diagnosis and treatment of breast tumorsleads to improved survival rates and quality of life.Women found to have benign lesions on biopsy are ableto avoid unnecessary treatment and receive reassurancethat they do not have breast cancer. Given the currentlyavailable alternatives, there is no need to conductrandomized controlled trials of breast biopsyprocedures. Establishing that a type of breast biopsy issafer than open surgical biopsy while being as accurate

or almost as accurate as open surgical biopsy issufficient to justify its routine use.

Studies of diagnostic test performance compare theresults of the experimental test to a reference test. Thereference test is intended to measure the “true” diseasestatus of each patient. For the diagnosis of breastcancer, the “gold standard” reference test is opensurgery and pathological examination of the removedtissue. However, a difficulty with the use of thisreference standard in large cohort studies of screening-detected breast abnormalities is that many women withlesions that are probably benign will be subjected toopen surgery. The principle of clinical equipoise meansthat there is genuine uncertainty over whether or not theintervention will be beneficial, and therefore it isacceptable to study the intervention in a clinicalresearch trial. Subjecting women with lesions that areprobably benign to open surgery does not meet theprinciple of clinical equipoise. Therefore we havechosen to include studies that used a combination offollowup and open surgical biopsy as the referencestandard in our analyses.

Studies of diagnostic test performance were examinedto see if they met the inclusion criteria. In brief, theinclusion criteria were: the study directly comparedcore-needle biopsy to pathological examination oftissue obtained by open surgery and/or patient followupfor at least 6 months; the study enrolled 10 or morepatients at average risk of primary breast cancer whowere referred for breast biopsy after discovery of apossible breast abnormality on screeningmammography, routine physical examination, or routineself-examination; the study was a full-length articlepublished in English; and 50 percent or more of theenrolled subjects completed the study.

In our analysis of biopsy accuracy, we focused onmeasures that evaluate the extent of false-negativeerrors (cancers falsely diagnosed as benign): sensitivityand negative likelihood ratio. Sensitivity is expressed asa percentage. A biopsy method with a sensitivity closeto 100 percent will miss very few cancers. A negativelikelihood ratio can be used to calculate an individualwoman’s risk of having a malignancy following a“benign” diagnosis on breast biopsy. In general, thesmaller the negative likelihood ratio, the more accurate

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the diagnostic test is in predicting the absence ofdisease. However, each individual woman’s post-testrisk varies by her individual pre-test risk of malignancy.

We also analyzed the “underestimation rate.” Lesionsdiagnosed by core-needle biopsy as ductal carcinoma insitu (DCIS, a noninvasive early stage of breast cancer)that were found to be invasive by the reference standardwere counted as DCIS underestimates. Similarly,lesions diagnosed by core-needle biopsy as benignatypical ductal hyperplasia (ADH) that were foundinstead to be invasive by the reference standard werecounted as ADH underestimates. The underestimationrate was then calculated as the number ofunderestimates per number of DCIS (or ADH)diagnoses. In the primary analysis of sensitivity andnegative likelihood ratio, underestimates were notconsidered to be missed cancers because currentclinical practice is to suggest surgical removal of ADHand DCIS lesions, and thus underestimates would nothave been “missed.”

The quality of the included studies was evaluated usingan internal validity rating instrument for diagnosticstudies. The studies were rated as low, moderate, orhigh in quality for the assessment of accuracyoutcomes. Data from the included articles wereabstracted and analyzed. Where possible, the data werecombined using a bivariate mixed-effects binomialregression meta-analysis model. Underestimation rateswere combined using a random-effects meta-analysis.The summary likelihood ratios and Bayes theorem wereused to compute post-test probabilities of a malignancy.

The strength of evidence supporting each majorconclusion was graded as high, moderate, low, orinsufficient. The grade was developed afterconsideration of the quality of the evidence base, thesize of the evidence base, the consistency of thefindings, and the robustness of the findings tosensitivity analyses.

Conclusions

Key Question 1. In women with a palpable ornonpalpable breast abnormality, what is theaccuracy of different types of core-needle breastbiopsy compared with open biopsy for diagnosis?

Our literature searches identified 107 studies of 57,088breast lesions that met the inclusion criteria. All of thestudies were diagnostic cohort studies that enrolled apopulation of women found to have suspicious breastabnormalities on routine screening (mammographyand/or physical examination). The women were sent forvarious types of breast biopsies, and the accuracy of thebreast biopsy was determined by comparing the resultsof the breast biopsy to the results of a combination ofopen surgery and patient followup. We graded thesupporting evidence for these conclusions as low basedon the low quality of the evidence base (i.e., greaterpotential for bias), although we rated the quantity,consistency, and robustness of the evidence base assufficient. Our conclusions for Key Question 1 aresummarized in Table A and Figures A through D. Ourkey conclusions are stated below.

• Stereotactically guided vacuum-assisted core-needle biopsies have a sensitivity of 99.2 percent(95-percent confidence interval [CI]: 97.9 to 99.7percent). Strength of evidence: Low.

• Stereotactically guided automated gun core-needlebiopsies have a sensitivity of 97.8 percent (95-percent CI: 95.8 to 98.9 percent). Strength ofevidence: Low.

• Ultrasound-guided vacuum-assisted core-needlebiopsies have a sensitivity of 96.5 percent (95-percent CI: 81.2 to 99.4 percent). Strength ofevidence: Low.

• Ultrasound-guided automated gun core-needlebiopsies have a sensitivity of 97.7 percent (95-percent CI: 97.2 to 98.2 percent). Strength ofevidence: Low.

• Freehand automated gun core-needle biopsies havea sensitivity of 85.8 percent (95-percent CI: 75.8 to92.1 percent). Strength of evidence: Low.

There was insufficient evidence to estimate theaccuracy of MRI-guided core-needle biopsies.

The included studies assumed that open surgical biopsywas 100-percent accurate. We obtained informationabout the actual accuracy of open surgical biopsy froma review article, and therefore a formal conclusion andstrength of evidence rating was not derived forestimates about the accuracy of open surgical biopsy.

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Key Question 2. In women with a palpable ornonpalpable breast abnormality, what are the harmsassociated with different types of core-needle breastbiopsy compared with open biopsy for diagnosis?

We recorded the complications and harms reported bythe 107 studies that met the inclusion criteria for KeyQuestion 1. Our results are summarized in Table B.Severe complications following core-needle biopsy ofany type are very rare, affecting fewer than 1 percent ofprocedures. Vacuum-assisted procedures may beassociated with slightly more severe bleeding eventsthan automated gun core-needle biopsies. The strengthof evidence supporting the quantitative estimates of thefrequency of complications is low. Information aboutharms of open surgical biopsy was scanty in theincluded studies, and we supplemented it withinformation from recent review articles. Therefore, thestrength of the evidence was not rated for conclusionsabout the safety of open surgical biopsy. However, it isclear that core-needle biopsies have a lower risk ofcomplications than do open surgical procedures.

In Figure E we present a simplified model of whatmight happen if the same cohort of 1,000 womenunderwent various types of breast biopsy. Thetheoretical cohort of women includes 300 women withmalignant tumors and 700 women with benign lesions.The model is based on the point estimates of accuracyfrom our analyses and do not incorporate estimates ofuncertainty of the point estimates. Refer to Figures Athrough D for a visual representation of the degree ofuncertainty in the point estimates. The model assumesthat all women with nonbenign diagnoses on their firstbiopsy procedure, including all women who had opensurgical biopsy as their first biopsy procedure, will besubject to an open surgical excisional procedure.

We also performed a number of meta-regressionsexploring the impact of various factors on the accuracyand harms of core-needle biopsies. Our findings fromthese meta-regressions are summarized in Table C. Useof image guidance and vacuum assistance improved theaccuracy of core-needle biopsy; however, vacuumassistance increased the percentage of procedurescomplicated by severe bleeding and hematomaformation. Performing biopsies with patients seatedupright increased the incidence of vasovagal reactions.

Our meta-regressions did not identify a statisticallysignificant effect of the following factors on the results:needle size, method of verification of biopsy (opensurgery, open surgery and at least 6 months’ followup,or open surgery and at least 2 years’ followup), whetherthe studies were conducted at a single center or atmultiple centers, whether the studies were conducted ingeneral hospitals or dedicated cancer clinics, or thecountry in which the study was conducted. The studiesreported insufficient information about lesioncharacteristics, patient characteristics, or the training orexperience of the persons performing the biopsies toexplore the effect of such factors on the accuracy orharms of the biopsies.

Key Question 3. How do open biopsy and variouscore-needle techniques differ in terms of patientpreference, availability, costs, availability of qualifiedpathologist interpretations, and other factors thatmay influence choice of a particular technique?

Due to the nature of Key Question 3, we did not useformal inclusion criteria, nor did we come to manyformal evidence-based conclusions. We collectedinformation relevant to the topic from many sources,including interviews with experts. There was generalagreement that core-needle biopsy costs less than opensurgical biopsy, consumes fewer resources, and ispreferred by patients. Women were generally satisfiedwith the cosmetic results of core-needle procedures.Women who underwent a core-needle biopsy as theirfirst invasive test to diagnose a breast cancer had, onaverage, fewer surgical procedures than women whounderwent an open biopsy procedure as their firstinvasive test. One particularly important finding wasthat women diagnosed with breast cancer by core-needle biopsy were usually able to have their cancertreated with a single surgical procedure, but womendiagnosed with breast cancer by open surgical biopsyoften required more than one surgical procedure to treattheir cancer (odds ratio 13.7, 95-percent CI: 5.6 to34.6). Due to the consistency, robustness, and extremelylarge strength of association between the type of biopsyand the requirement for more than one surgery fortreatment, we rated the strength of evidence supportingthis conclusion as moderate. There was insufficientinformation available to evaluate the impact ofequipment or pathologist availability.

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Discussion

When making decisions about what type of biopsy touse, individual women and their health care providerswill need to weigh the pros and cons of each type ofbiopsy for each individual woman. Open surgicalbiopsies are highly accurate; however, core-needlebiopsies are associated with a much lower incidence ofharms and morbidity. In addition, women who arediagnosed with cancer by core-needle biopsy undergofewer surgeries during treatment than do women whoare diagnosed with cancer by open biopsy. The crux ofthe decision then becomes the question, “Is core-needlebiopsy accurate enough?” The answer to this questionmay vary depending on the individual woman’sestimated prebiopsy chance of having cancer (anestimate derived from mammography results and otherprebiopsy examination information) and an individualwoman’s desire to avoid risk. For some women, core-needle biopsy will never be accurate enough to satisfytheir desire to know, for sure, whether they do or do nothave cancer. For others, the greater safety and lessinvasive nature of core-needle biopsy are worth a smallsacrifice in accuracy. During decisionmaking, womenand health care providers also need to consider theclinical implications of a cancer missed on core-needlebiopsy. In many cases, the cancer will be detected onsubsequent mammography. Women with negative core-needle biopsies should have careful diagnostic followupwth clinical correlation as appropriate for the individualpatient.

The ratings of low strength of evidence apply to theindividual estimates of accuracy for each type of core-needle biopsy. Due to the poor reporting and lowinternal validity of the included studies, we areconcerned that the studies may be consistently biasedtoward finding that core-needle biopsies are moreaccurate than they actually are. We have performedsensitivity analyses (Table D) of the impact of thispossibility on our conclusions. For each biopsy method,we have estimated the post-test probability of a womanactually having cancer after a negative core-needlebiopsy result (assuming the woman had a prebiopsyprobability of having cancer of 30 percent). We

calculated probabilities using the summary estimate ofthe negative likelihood ratio from our analysis, and forsummary estimates calculated after assuming ouranalysis had overestimated the sensitivity of theprocedure by 1 percent, 5 percent, and 10 percent. Weare moderately confident that our analysis has notoverestimated the sensitivity by as much as 10 percent,but we present the results of this sensitivity analysis asa “worst case” scenario. For example, for ultrasound(US) guidance vacuum-assisted core-needle biopsy, weestimated the probability of a woman actually havingcancer after a negative core-needle biopsy result to be 2percent. Sensitivity analyses using overestimation of thesensitivity by 5 percent and 10 percent suggest that thisprobability would increase to 3 percent and 6 percent,respectively.

Remaining Issues

Our systematic review has found that bothstereotactically guided vacuum-assisted and US-guidedcore-needle biopsies are safer than open surgical biopsyand are almost as accurate as open surgical biopsy,justifying their routine use. However, well-reportedretrospective chart reviews, retrospective databaseanalyses, or prospective diagnostic accuracy studies areneeded to address the as-yet-unanswered questions as towhat factors affect the accuracy and harms of core-needle breast biopsy. Answers to such questions areimportant for both patients and clinicians when facedwith the decision of what type of breast biopsy is bestfor each individual patient. In addition, our conclusionsare rated as being supported by a low strength ofevidence. The low rating is almost entirely due to thefact that the evidence base, while large, consists ofuniversally poorly reported studies. The studies omittedimportant details about patients, methods, andsometimes results. The studies presented results in anoften confusing and haphazard manner. The poorreporting made it difficult to determine whether or notthe studies were likely to be affected by bias, andtherefore we rated the evidence base as being of lowquality. Publication of better reported diagnosticaccuracy studies would permit verification that our

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conclusions are accurate and not influenced by biases inthe studies included in this assessment. Additionalstudies of MRI-guided biopsy are necessary in order toevaluate the accuracy and safety of MRI guidance.

Summary

An overall summary of the findings and level ofevidence for each biopsy type is presented in Table E.Based on currently available evidence, it appearsreasonable to consider choosing certain core-needlebiopsy procedures given the comparable sensitivity andlower complication rates for some of the percutaneousmethods. Our analyses found the highest sensitivity formethods utilizing stereotactic guidance, particularly inconjunction with vacuum assistance. The appearance ofbreast lesions on imaging and the location within thebreast may affect the type of core needle/imagingcombination chosen for any particular woman. Ingeneral, women undergoing core needle biopsy aresubjected to fewer surgical procedures overall thanwomen who initially are diagnosed by open surgicalbiopsy, and they express satisfaction with the cosmeticresults. However, the available studies suffered frompoor reporting of important details that would help toidentify patient and lesion characteristics that mightimpact the validity of this conclusion for individualwomen. We rated the strength of evidence as low forthe accuracy outcomes, in large part because the

absence of these details also compromised our ability toassess the risk of bias in the published studies. We haveidentified a number of questions that should beanswered by future studies in order to improveindividualized decisionmaking.

Full Report

This executive summary is part of the followingdocument: Bruening W, Schoelles K, Treadwell J,Launders J, Fontanarosa J, Tipton K. ComparativeEffectiveness of Core-Needle and Open SurgicalBiopsy for the Diagnosis of Breast Lesions.Comparative Effectiveness Review No. 19. (Preparedby ECRI Institute Evidence-based Practice Centerunder Contract No. 290-02-0019.) Rockville, MD:Agency for Healthcare Research and Quality.December 2009. Available at:www.effectivehealthcare.ahrq.gov/reports/final.cfm.

For More Copies

For more copies of Comparative Effectiveness of Core-Needle and Open Surgical Biopsy for the Diagnosis ofBreast Lesions: Comparative Effectiveness ReviewExecutive Summary No. 19 (AHRQ Pub. No. 10-EHC007-1), please call the AHRQ Clearinghouse at1-800-358-9295 or e-mail [email protected].

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Table A. Summary of key accuracy findings (Key Question 1)

Number of Number ofNumber of malignancies invasive missed Risk of expected per cancers cancers malignancy 1,000 biopsy expected per Strength ofexpected for following diagnoses of 1,000 biopsy evidenceevery 1,000 a “benign” “high risk” diagnoses of supporting the

Type of biopsy biopsies1 test result2 lesion3 DCIS conclusion

Open surgical4 3 to 6 0 to 1% 0 0 Not rated

Freehand automated 24 to 73 3.4 to 10% Insufficient data to estimate Lowgun

US guidance 6 to 9 1 to 2% 234 to 359 271 to 450 Lowautomated gun

Stereotactic guidance 3 to 13 0.5 to 2% 357 to 517 180 to 321 Lowautomated gun

MRI guidance Insufficient data to estimate Insufficientautomated gun

US guidance 2 to 56 0.3 to 8% Insufficient data to estimate Lowvacuum-assisted

Stereotactic guidance 1 to 6 0.1 to 1% 177 to 264 111 to 151 Lowvacuum-assisted

1 For a population of women with a prevalence of malignancy of 30%, assuming a 100% specificity (no false positives).2 For a woman with a BI-RADS® 4 score following mammography expected to have an approximate prebiopsy risk of malignancy of 30%.Note that an individual woman’s risk may be different from these estimates, depending on her own individual characteristics.3 Primarily ADH lesions.4 Estimates based on other literature reviews.

Abbreviations:ADH=atypical ductal hyperplasia; DCIS=ductal carcinoma in situ; MRI=magnetic resonance imaging; US=ultrasound.

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Table B. Summary of key harms findings (Key Question 2)

Number ofcases of

Number of hematomasNumber of cases of severe requiring Number of Strength ofdeaths bleeding1 treatment infections evidenceexpected for expected for expected for expected for supportingevery 1,000 every 1,000 every 1,000 every 1,000 the

Type of biopsy biopsies biopsies biopsies biopsies conclusion

Open surgical2 0 Insufficient data 20 to 100 38 to 63 Not ratedto estimate

Automated gun 0 6 1 1 Lowcore needle

Vacuum-assisted 0 9 1 1 Lowcore needle

1 Although not all studies provided a definition of severe bleeding, those that did included episodes of bleeding necessitating treatment,including hospitalization or surgery.

2 Estimates based on other literature reviews.

Table C. Summary of impact of various factors on accuracy and harms

Strength ofevidence

Impact on Impact on supporting the Category Factor accuracy harms conclusion

Patient characteristics Insufficient data for any patient characteristics Insufficient

Lesion characteristics Insufficient data for any lesion characteristics Insufficient

Biopsy methods Patient position Insufficient data Vasovagal reactions Lowoccur more often in patients seated upright

Needle gauge Does not affect Insufficient data Lowaccuracy

Insufficient data for any other factor related to biopsy methods Insufficient

Clinician characteristics Operator Accuracy improves Insufficient data Insufficientexperience with experience

Insufficient data for any other factor related to clinician Inconclusivecharacteristics

Facility type Type of facility Does not affect Insufficient data Lowaccuracy

Geographic Does not affect Insufficient data Lowlocation of facility accuracy

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Table D. Sensitivity analysis of impact of low quality evidence on the conclusions

Post-biopsy probability of having cancer after a negative core-needle biopsy result1

Analysis Analysis Analysisoverestimated overestimated overestimatedsensitivity by sensitivity by sensitivity by 1% (e.g., 5% (e.g., 10% (e.g.,sensitivity sensitivity sensitivity

Analysis 97% rather 93% rather 88% rather Type of biopsy results than 98%) than 98%) than 98%)

Freehand automated gun 6% 6% 8% 9%

Ultrasound guidance 1% 1% 3% 5%automated gun

Stereotactic guidance 1% 1% 3% 5%automated gun

Ultrasound guidance 2% 2% 3% 6%vacuum-assisted

Stereotactic guidance 0.4% 0.8% 3% 5%vacuum-assisted

1 For a woman with a BI-RADS® 4 score following mammography expected to have an approximate prebiopsy risk of malignancy of 30%.Note that an individual woman’s risk may be different from these estimates, depending on her own individual characteristics.

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Table E. Summary of all findings on comparative effectiveness of core-needle biopsy methods

Accuracy

Type of guidance Method of biopsy Level of evidence Sensitivity (95% CI)

Any or none Open surgical Not rated 98% to 99%

Stereotactic Automated gun Low 97.8% (95.8 to 98.9)

Vacuum-assisted Low 99.2% (97.9 to 99.7)

Ultrasound Automated gun Low 97.7% (97.2 to 98.2)


MRI Automated gun Insufficient 83.3% (43.5 to 96.5)

Freehand Automated gun Low 85.8% (75.8 to 92.1)

Type of guidance Method of biopsy Level of evidence Negative likelihood ratio (95% CI)

Any or none Open surgical Not rated 0.00 to 0.025

Stereotactic Automated gun Low 0.022 (0.012 to 0.043)

Vacuum-assisted Low 0.0090 (0.003 to 0.023)

Ultrasound Automated gun Low 0.030 (0.022 to 0.040)

Vacuum-assisted Low 0.036 (0.0060 to 0.21)

MRI Any Insufficient 0.23 (0.05 to 0.95)

Freehand Automated gun Low 0.14 (0.082 to 0.25)

Type of guidance Method of biopsy Level of evidence DCIS underestimation rate (95% CI)

Any or none Open surgical Not rated 0.0%




Vacuum-assisted Insufficient Not possible to calculate

MRI Any Insufficient Not possible to calculate

Freehand Automated gun Insufficient Not possible to calculate

Type of guidance Method of biopsy Level of evidence ADH underestimation rate (95% CI)

Any or none Open surgical Not rated 0.0%




Vacuum-assisted Insufficient Not possible to calculate

MRI Any Insufficient Not possible to calculate

Freehand Automated gun Insufficient Not possible to calculate

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Table E. Summary of all findings on comparative effectiveness of core-needle biopsy methods (continued)

Factors potentially affecting accuracy

Conclusion about impact of Factor category Factor Level of evidence factor on accuracy

Patient characteristics Patient age Insufficient No conclusion possible

Breast density Insufficient No conclusion possible

Patient comorbidities Insufficient No conclusion possible

Lesion characteristics Palpable vs. nonpalpable Insufficient No conclusion possible

Microcalcifications vs. Insufficient No conclusion possiblemasses

Distortions vs. masses Insufficient No conclusion possible

Size of lesion Insufficient No conclusion possible

Location of lesion Insufficient No conclusion possible

Biopsy methodology Number of cores Insufficient No conclusion possible

Patient position Insufficient No conclusion possible

Reference standard Not rated The type of reference standard (open surgery, 2 years’ of followup, or only 6 months’ of followup) had no impact on the data reported by the studies about the accuracy of core-needle biopsy

Use of vacuum Low Vacuum assistance improved accuracy

Use of image guidance Low Use of image guidance improved accuracy; stereotactic guidance was more accurate than US guidance

Size of needle Not rated The size of the needle did not affect the accuracy of the procedure

Clinician and facility Experience of operator Insufficient No conclusion possiblefactors

Training of operator Insufficient No conclusion possible

Facility location Not rated The location of the facility had no impact on the accuracy of core-needle biopsy

Facility type Not rated The type of facility had no impact on the accuracy of core-needle biopsy

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Harms

Harm category Harm Level of evidence Conclusion

Number of surgeries Undergoing surgery Moderate Women diagnosed with breast cancer required by core-needle biopsies are more likely

to be able to be treated with a single surgical procedure than women diagnosed with breast cancer by open surgical biopsies

Complications Any High Core-needle biopsies have a lower risk of complications than open surgical procedures

Severe complications Any Low 2 to 10% of open surgical procedures may be affected by severe complications; 0.09 to 0.72% of core-needle biopsy procedures may be affected by severe complications

Deaths Low No deaths were reported in association with any type of breast biopsy procedure

Bleeding severe enough Low 0.72% of core-needle procedures were to require treatment affected by severe bleeding

Hematomas requiring Low 0.09% of core-needle procedures were treatment affected by hematomas requiring

treatment

Infections Low 0.15% of core-needle procedures were affected by infections requiring antibiotic treatment

Severe pain Low 1.7% of patients reported experiencing severe pain during core-needle procedures

Minor complications Bruising Low Bruising following core-needle procedures was reported to be common

Vasovagal reactions Low 1.0% of patients had vasovagal reactions during core-needle procedures

Pain Low 3.7% of patients required pain medications following core-needle procedures

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Factors potentially affecting harms

Conclusion about impact of factor on Factor category Factor Level of evidence harms

Patient characteristics Patient age Insufficient No conclusion possible

Breast density Insufficient No conclusion possible

Patient comorbidities Insufficient No conclusion possible

Lesion characteristics Palpable vs. nonpalpable Insufficient No conclusion possible

Microcalcifications vs. Insufficient No conclusion possiblemasses

Distortions vs. masses Insufficient No conclusion possible

Size of lesion Insufficient No conclusion possible

Location of lesion Insufficient No conclusion possible

Biopsy methodology Number of cores Insufficient No conclusion possible

Patient position Low Vasovagal reactions occur more often in patients seated upright

Reference standard Insufficient No conclusion possible

Use of vacuum Low Use of vacuum increased the percentage of procedures complicated by severe bleeding and hematoma formation

Use of image guidance Insufficient No conclusion possible

Size of needle Insufficient No conclusion possible

Clinician and facility Experience of operator Insufficient No conclusion possiblefactors

Training of operator Insufficient No conclusion possible

Facility location Insufficient No conclusion possible

Facility type Insufficient No conclusion possible

Abbreviations:ADH=atypical ductal hyperplasia; CI=confidence interval; DCIS=ductal carcinoma in situ; MRI=magneticresonance imaging; US=ultrasound.

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Figure A. Sensitivity of different types of biopsy

Sensitivity = (true positives/ (true positives + false negatives))*100.

Freehand automated gun: 5 studies of 610 biopsies.

US vacuum-assisted: 7 studies of 507 biopsies.

US automated gun: 16 studies of 7,124 biopsies.

Stereotactic automated gun: 33 studies of 7,135 biopsies.

Stereotactic vacuum-assisted: 22 studies of 7,512 biopsies.

Open surgical estimate based on other literature reviews.

Abbreviation: US=ultrasound.

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Negative likelihood ratio = (false negatives/(true positives + false negatives)/(true negatives/false positives + true negatives).

Freehand automated gun: 5 studies of 610 biopsies.

US vacuum-assisted: 7 studies of 507 biopsies.

US automated gun: 16 studies of 7,124 biopsies.

Stereotactic automated gun: 33 studies of 7,135 biopsies.

Stereotactic vacuum-assisted: 22 studies of 7,512 biopsies.


Abbreviation: US=ultrasound.

Figure B. Negative likelihood ratios of different types of biopsy

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Figure C. DCIS underestimation rates of different types of biopsy

DCIS underestimation = (number cases diagnosed as DCIS on core-needle biopsy that were found to be invasive cancer by the referencestandard)/(total number cases diagnosed as DCIS on core-needle biopsy)*100.

US automated gun: 12 studies of 208 core-needle diagnoses of DCIS.

Stereotactic automated gun: 19 studies of 694 core-needle diagnoses of DCIS.

Stereotactic vacuum-assisted: 21 studies of 1,224 core-needle diagnoses of DCIS.


Abbreviations: DCIS=ductal carcinoma in situ; US=ultrasound.

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Figure D. ADH underestimation rates of different types of biopsy

ADH underestimation = (number cases diagnosed as ADH on core-needle biopsy that were found to be invasive or in situ cancer by thereference standard)/(total number cases diagnosed as ADH on core-needle biopsy)*100.

US automated gun: 13 studies of 207 core-needle diagnoses of ADH.

Stereotactic automated gun: 26 studies of 321 core-needle diagnoses of ADH.

Stereotactic vacuum-assisted: 21 studies of 380 core-needle diagnoses of ADH.


Abbreviations: ADH=atypical ductal hyperplasia; US=ultrasound.

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Figure E. Models of 1,000 women undergoing breast biopsy

Abbreviation: US=ultrasound.The numbers may not sum to exactly 1,000 due to rounding.

AHRQ Pub. No. 10-EHC007-1December 2009

comparative effectiveness of core-needle and open surgical ... · routine breast cancer screening...

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