BREAST CANCER IN PREGNANCY

SADAF ALIPOURASSISTANT PROFESSOR

GENERAL SURGEONTEHRAN UNIVERSITY OF MEDICAL

SCIENCES

INTRODUCTION

 Gestational or pregnancy-associated breast cancer is defined as breast cancer that is diagnosed during pregnancy, in the first postpartum year, or any time during lactation.

A CHALLENGING CLINICAL SITUATION

Welfare of both mother and fetus must be taken into account in any treatment planning

Prospective studies are very few Much of the clinical evidence is

limited to retrospective case series and case reports.

INCIDENCE

One of the most common cancers in nonpregnant and pregnant women

Up to %20 of BCs under 30 are Py-associated

Fewer than %5 of BCs diagnosed under 50 are detected during Py or in postpartum

EPIDEMIOLOGY

A relatively uncommon event. Incidence: 15-35 per 100,000

deliveries Fewer cases during Py than in

first postpartum year Incidence appears to be

increasing as more women delay childbearing

PATHOLOGY

Majority : infiltrating ductal carcinomas, as in nonpregnants

But predominantly poorly differentiated and advanced stage, esp. those in lactation

May higher incidence of inflammatory breast cancer than nonpregnants

Most series report lower frequency of ER and PR compared to nonpregnants(% 25 versus %55- 60)

PRESENTATION

Usually present similarly to nonpregnants

Mass or thickening in the breast Rarely, a nursing infant has refused

a breast that harbors an occult carcinoma, leading to an early diagnosis of breast cancer; this has been named the milk rejection sign

DIAGNOSIS (1)

Physiologic changes in the breast in pregnancy (eg, engorgement and hypertrophy) make examination more challenging, interpretation of findings more difficult, and limit the utility of mammography

Diagnostic delays of 2m or longer common Such delays may adversely impact outcome,

since even a one month delay in diagnosis can increase the risk of nodal involvement by 1 to 2 percent

Index of suspicion for cancer must be high in Py with a breast mass

DIAGNOSIS (2)

Index of suspicion for cancer must be high in Py with a breast mass

A breast mass that persists for more than two weeks should be investigated, although the majority (80 percent) will be benign

DIFFERENTIAL DIAGNOSIS A breast mass in a pregnant or lactating woman can

be: breast cancer, lactating adenoma, fibroadenoma, cystic disease, lobular hyperplasia, milk retention cyst (galactocele), abscess, lipoma, hamartoma, and rarely, leukemia, lymphoma, phyllodes tumors,

sarcoma, neuroma, or tuberculosis

MAMMOGRAPHY (1)

Not contraindicated in pregnancy

Average dose to breasts for a two-view mammogram (200 to 400 millirad) provides a negligible radiation dose to the fetus

Abdominal shielding is recommended.

MAMMOGRAPHY (2)

Sensitivity is altered by changes of pregnant or lactating breasts:

increased water content, higher density loss of contrasting fat Nevertheless, data suggest that

mammography is sufficiently sensitive to diagnose breast cancer during pregnancy and lactation

ULTRASONOGRAPHY

Often the first imaging test ordered to evaluate a breast mass in a pregnant woman

Determines simple or complex cysts or solid tumors without risk of fetal radiation exposure

A focal solid mass is observed in majority of gestational BCs

MRI (1)

Not systematically studied for gestational breast masses

No harmful effects from MRI during pregnancy have been reported

But the National Radiological Protection Board avoids it in T1 if possible since limited experience during organogenesis

However, MRI considered in T1 when benefits exceed risks

MRI (2)

Gadolinium-enhanced MRI more sensitive than mammography for detecting invasive breast cancer, esp. with dense breasts

But gadolinium avoided in pregnancy due to potentially long half-life in fetus and lack of safety information.

Gadolinium-enhanced breast MRI may be considered in postpartum

BIOPSY  A clinically suspicious breast

mass requires biopsy for definitive diagnosis, regardless of whether or not a woman is pregnant, and despite negative mammographic or ultrasound findings.

Core, incisional, or excisionalBx relatively safe during Py, preferably under LA

LYMPH NODES

Debate over safety and efficacy of sentinel lymph node biopsy in Py-associated BC

Areas at risk for and/or clinically suspicious for LAP should be further evaluated with US and FNA

SYSTEMIC STAGING

Tendency to Dx at advanced stage As in nonpregnants, locally advanced

stage BC [stage III or IV ] and/or suspicious symptoms should prompt complete staging

In contrast, if asymptomatic and clinically node-negative and early stage, no need for evaluation of lung, liver, bone, or brain metastases

LUNG METASTASES

For lung metastases: CXR with abdominal shielding

Estimated dose to the fetus :0.06 millirad. Ability to evaluate lower lung parenchyma

with CXR limited late in gestation when gravid uterus pressing against diaphragm.

CTscan generally avoided in Py because of the large cumulative radiation dose with multiple slices

If further evaluation of chest warranted:MRI preferred but gadolinium avoided

 LIVER METASTASES

US safe for evaluation in Py but significantly less sensitive than CT or MRI

CT of abdomen or pelvis not performed in Py

MRI preferred if further visceral organ evaluation required

National Radiological Protection Board advises MRI be avoided in T1 if possible

BRAIN METASTASES

If suspected: MRI the safest and most sensitive way

Information regarding safety and efficacy of PET in Py limited

BONE EVALUATION: RADIONUCLIDE BONE SCAN

Safe in Py. A "low-dose" bone scan described that

exposes fetus to 0.08 rad as compared to the standard 0.19 rad for a conventional bone scan

Fetal exposure may also result from proximity to radionuclides excreted in bladder:

Maternal hydration and frequent voiding can reduce this exposure.

Not recommended in absence of signs or symptoms of bone abnormality.

BONE EVALUATION:SKELETAL MRI May be considered as alternative to bone scan, (without

contrast until further safety data are available). Since breast metastases are deposited in red marrow,

imaging of axial skeleton (spine, pelvis, ribs and sternum) include approximately %80 of all metastatic sites

Alternatively, screening MRI of thoracic and lumbar spine may be considered if no complaints of extraspinal bony metastases

The safety of plain skeletal radiographs is unclear. Although these films result in less than 1 rad exposure to the fetus and have been obtained during pregnancy by obstetricians for pelvimetry measurements and to evaluate for renal stones, even low levels of ionizing radiation may increase the risk of childhood leukemia

BONE EVALUATION: ALKALINE PHOSPHATASE

Increases markedly during Py due to placental production

Cannot be used as indicator of bone metastases

Even bone specific ALP is not a reliable measure of bone disease.

MONITORING OF PREGNANCY

The pregnant woman with BC requires careful and continuous monitoring of her Py by her obstetrician

Confirmation of gestational age and EDC important

Aniocentesis may be required to determine pulmonary maturity if early delivery is being considered.

NOTE: Early termination of Py does not improve

survival of gestational BC and some series suggest a decreased survival associated with early termination of Py

Indications of local and systemic adjuvant therapy are similar to non- pregnants

Herceptin and endocrine therapy are not safe during any trimester of Py. When these therapies are administered post- partum, breast feeding should be avoided

SUMMARY AND RECOMMENDATIONS

Gestational or Py-associated BC is a BC diagnosed in Py, 1st postpartum year, or any time during lactation

A relatively uncommon event although one of the most common cancers in Py

Incidence increasing as more women delay Py Predominantly poorly differentiated and

advanced Index of suspicion for cancer must be high in

Py with a breast mass Breast US and mammo in any suspicious mass Clinical suspicion requires Bx for definitive Dx

REFERENCES

1- Schwartz Principles of Surgery (book) 2- Diseases of the Breast (book) 3-UptoDate (online)

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