treated with dynamic IMRT using inverse planning. An anterior conventional lower neck field with spinal cord shield was usedto irradiate the lower neck and supraclavicular area. A contralateral parotid-sparing technique with IMRT-SMART strategy wasused. CTV1 was treated with an accelerated fractionation, while conventional dose schedule to CTV2 was preserved. In 30patients without extracapsular extension and with negative margins a total dose of 56 Gy (2.24 Gy/fraction) and 50 Gy (2Gy/fraction) to PTV1 and PTV2, respectively was delivered simultaneously in 25 fractions. In the remaining 4 patients withpositive margins and/or extracapsular extension, a total dose of 64 Gy (2.13 Gy/fraction) and 54 Gy (1.8 Gy/fraction) to PTV1and PTV2, respectively was administered in 30 fractions.

Results: The median follow-up was 24 months (range 10 - 48 months). Four local failures occurred at 9, 10, 12 and 25 months.The 2 year local-regional control rate was 91%. The 2 year overall survival was 93 %. The average mean dose to thecontralateral parotid gland was 22 Gy (11–30 Gy). In 30 patients mean dose to the contralateral parotid was �24 Gy, (3 pts25–26 Gy, only in 1 patient 30 Gy). Grade 3–4 CTC acute toxicity occurred in 23 patients (68 %). None of the patients hadGrade 3–4 RTOG/EORTC late toxicity.

Conclusions: SMART strategy was used in the treatment of postoperative oropharyngeal and oral cavity cancers. Ahomogeneous target coverage with a substantial parotid sparing was achieved. The local regional control and overall survivalrates were excellent with reasonable toxicity. SMART-IMRT proved to be feasible. It provided measures of biological doseescalation, thus shortening overall treatment time. In addition, the workload on treatment planning and linear accelerators canbe considerably reduced through singe plan and accelerated regimen.

Author Disclosure: L. Schlenger, None; F. Ataman, None; I. Eichwurzel, None; V. Budach, None.

2444 Megavoltage CT Assessment of Volume Changes in Target and Non-Target Tissues of the Head and NeckOver a Standard Course of Therapy

G. K. Bajaj, T. Teslow, M. H. Yu, D. J. Lee, E. Ford

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD

Purpose/Objective(s): Intensity Modulated Radiation Therapy (IMRT) is widely utilized for parotid gland sparing andimproved gross tumor coverage in patients with head and neck cancer. IMRT incorporates large dose gradients between thesetarget and non-target tissues and current treatment delivery methods assume minimal to no change in the volumes of non-targettissues over the treatment course. Adaptive radiation therapy strategies have focused on change in volume of the primary tumoras a basis for modification of the delivery plan. However, as parotid sparing is often the primary basis for IMRT utilization inthis population of patients, large changes in volume of these structures during the course of therapy may result in significantalteration of originally defined dose to volume delivery parameters set forth at the initiation of therapy. Our analysis seeks toquantify volume changes in the parotid glands over a course of therapy to further elucidate how optimization of parotid dosemay be attained in future applications of adaptive and image guided planning.

Materials/Methods: Four megavoltage CT (MV CT) images were acquired at two week intervals for 7 patients treated withthe TomoTherapy® treatment system and imported into the Pinnacle treatment planning system v.7.9u (ADAC/Philips Inc.).Rigid co-registration was performed to the radiation treatment planning CT via bony landmarks. Gross tumor volumes (GTV)and parotid gland volumes were delineated on the MV CT using the image fusion interface and volumes and centroid locationswere calculated.

Results: GTV volume decreased to an average of 22% (Range 15–28%) of original volume by week six of therapy. Evaluationof single parotid gland volumes revealed an increase in average volume during the first four weeks of therapy to 120% (Range:64%-160%) of the original volume at day 0, with maximal average volume at day 17 of treatment. Thereafter, average glandvolume dropped to 91% (Range 73–119%) of the original volume by week 6 of therapy.

Conclusions: In addition to expected overall decrease in GTV volumes, salivary gland volumes also varied substantially overa standard course of radiotherapy in our cohort; initially increasing in volume during the first half of the treatment course andthen slowly regressing in volume over the second half. Adaptive planning approaches in the head and neck cancer populationmust also consider potentially large volume changes in non-target salivary tissue in order to accurately achieve and optimizeintended dose constraints to these organs.

Author Disclosure: G.K. Bajaj, None; T. Teslow, None; M.H. Yu, None; D.J. Lee, None; E. Ford, None.

2445 Accelerated Radiation Therapy and Concurrent Chemotherapy for Advanced Oropharyngeal Cancer

I. Deutsch1, K. Hu2, B. Culliney2, S. Malamud2, D. Frank2, M. Persky2, S. Schantz3, R. Sessions2, M. Urken4, L. B.Harrison2

1SUNY Downstate Medical Center, Brooklyn, NY, 2Beth Israel Medical Center, New York, NY, 3New York Eye and EarInfirmary, New York, NY, 4Beth Israel Medical Center, Brooklyn, NY

Purpose/Objective(s): Concurrent chemoradiation and accelerated radiation have improved locoregional control in locallyadvanced squamous cell carcinoma of the head and neck . Accelerated radiation by delayed concomitant boost radiotherapy(DCBRT) with concomitant platinum chemotherapy may yet further improve outcomes but may also increase toxicity. Wereport on Beth Israel Medical Center’s experience treating advanced oropharyngeal squamous cell carcinoma (OSCC) with theabove regimen.

Materials/Methods: From 1/98 to 10/05, forty patients with locoregionally advanced OSCC were treated with DCBRT (1.8Gy/d weeks 1 to 6; boost: 1.6 Gy 4 to 6 hours later weeks 5 to 6; 70 Gy total dose to gross disease), and concomitantchemotherapy, either cisplatin (100 mg/m2 weeks 1 and 4), or carboplatin in a daily (10–17.5mg/m2) or weekly regimen (AUC2). Patients with N2–3 disease underwent planned neck dissection. Median age: 55, (range 37–83). Males: 33 patients. T1: 4(10%), T2: 8 (20%), T3: 9 (22.5%), T4a: 10 (25%), and T4b: 9 (22.5%) each. N0: 4 (10%), N1: 5 (12.5%), N2/3: 31 (57.5%).M1: 1 patient. Stage II: 1 (2.5%), III: 3 (7.5%), IVA: 19 (47.5%), IVB: 16 (40%), IVC: 1 (2.5%). Median dose: 70 Gy.

S456 I. J. Radiation Oncology ● Biology ● Physics Volume 66, Number 3, Supplement, 2006

Ninety-six percent of patients were able complete the prescribed radiation while 22 patients had CDDP chemotherapy, 13 hadcarboplatin. Kaplan Meier estimates were used to calculate survival curves.

Results: Mean followup was 18.5 months (range 2–89 months). Kaplan Meier estimates of 2 year local control, regionalcontrol, locoregional control, freedom for distant metastasis, disease-free survival and overall survival were 81%, 97%, 81%,74%, 76%, and 80%, respectively. Six patients had local disease, 5 from persistence after chemoradiation, and 1 from recurrence(within 1 year). Four of the patients with disease had �� 5 days of treatment break, and 5 of them had Stage IVB disease. Of7 distant failures, 6 were within the 1st year, and 1 was at 19 mos. The most common acute CTC grade 3 toxicities: mucositis:67.5%, dysphagia: 62.5%, odynophagia: 62.5%, and 28.9% were hospitalized during treatment, most commonly for dehydra-tion. Median break days during treatment: 2.24 (range 0–8).Mean weight loss: 11.11%, median: 12% (range 0–26%). The meanpretreatment hemoglobin (Hgb): 13, mean end treatment Hgb: 11.38. Grade 3 Hgb toxicity: 17.5%. Late toxicities: grade 3 /4 xerostomia: 36%/ 2.2%, dysphagia: 11.1%. There was 1 incidence of osteonecrosis, and 1 of soft tissue necrosis. 80% hadPEG placed before or during treatment. Two of 25 patients with available data still had the PEG in place at 5 months (nottolerating any PO) and 17 months (tolerating only liquid PO) from the end of treatment. When comparing outcomes of thosereceiving carboplatin vs cisplatin, no difference was noted for LRC, or FFDM, but a difference was noted for mean acute NCICTC grade of anemia (CDDP 1.5 vs 0.58 for carboplatin, p�0.027). Mean weight loss for the carboplatin group was 11% versus14% for the CDDP group (p�0.4).

Conclusions: On preliminary analysis, DCBRT with concomitant platinum chemotherapy, in the setting of advanced OSCCyields excellent locoregional control, with good tolerance and a low rate of PEG dependence. Carboplatin appeared to betolerated better hematologically.

Author Disclosure: I. Deutsch, None; K. Hu, None; B. Culliney, None; S. Malamud, None; D. Frank, None; M. Persky, None;S. Schantz, None; R. Sessions, None; M. Urken, None; L.B. Harrison, None.

2446 Analysis of the Effect of T3–4N0–3 Stage Nasopharyngeal Carcinoma With Radiotherapy Alone

C. Chen, T. X. Lu, C. Zhao, Y. Sun, L. X. Lu, F. Han, X. F. Liu

Department of Radiation Oncology, Cancer Center, Sun Yat-Sen University, Guangzhou, China

Background: Before the 1980’s, most of the patients with non-disseminated nasopharyngeal carcinoma received the treatmentof radiotherapy alone. The 5-year overall survival rate was 47%-52%, with 40%-50% for stage III and 22%-24% for stage IV.The major causes of treatment failure are local-regional relapse and distant metastasis. However, we’re still uncertain aboutwhether the locally advanced or the regionally advanced stage plays a more important role in the survival of the local-regionallyadvanced patients.

Purpose/Objective(s): To discuss the impact of different T (loacl) and N (regional) stage for local-regionally advancednasopharyngeal carcinoma (NPC) on the clinical gains of radical radiotherapy (RT) alone.

Materials/Methods: From January to December in 1999, 556 patients with 92 Fuzhou stage T3–4N0–3M0 in China wereinitially treated by conventional RT alone with the facio-cervical fields technique. All were retrospectively reviewed. The totaldose was 66–80Gy / 6.5–8.0 weeks in the nasopharynx lesion, and 60–70 Gy / 6–7 weeks in the neck lymph nodes.

Results: The overall 5-year survival rate (OS) was 66.41%, and with 69.12%,58.96% in T3,T4 stage ( P� 0.05 ).However, thelocal control, disease-free survival, relapse-free survival (RFS) or metastasis-free (MFS) rate showed no significant differencein T3 and T4 stage. The 5-year OS was 73.98%, 65.96%, 57.58% and 29.39% in N0, N1, N2 and N3 stage, respectively (P�0.01).The relapse and distant metastasis rate was significantly higher for patients with more advanced N stage.The 5-yearlocally-relapse-free rate 70.29%, 62.92%, 52.95% and 29.68% for N0, N1, N2 and N3 stage respectively (P� 0.01), and theregionally-relapse-free rate 73.51%, 64.78%, 56.15% and 29.39% for N0, N1, N2 and N3 stage respectively (P� 0.01). Themetastasis-free rate was 71.52%, 61.80%, 51.66% and 27.80% for N0, N1, N2 and N3 stage respectively (P� 0.01 ).

Conclusions: We conclude that N stage is the dominant factor influenced the effect and prognosis for patients withlocal-regionally advanced NPC treated by conventional RT alone. T stage was only the minor correlative factor. Using stratifiedcombined radio-chemotherapy modality for different N stage of local-regional advanced NPC may act positively and effectivelyon resolving the cause of treatment failure&endash; relapse and distant metastasis.

Author Disclosure: C. Chen, None; T.X. Lu, None; C. Zhao, None; Y. Sun, None; L.X. Lu, None; F. Han, None; X.F. Liu,None.

5-year treatment effectiveness for stage T3-4N0-3M0

StagePatient

Numbers5-YearOS(%) P Value

5-YearRFS(%) P Value

5-YearMFS(%) P Value

T3 382 69.12 62.75 64.65T4 174 58.96 �0.05 54.89 0.05 55.47 0.05N0 179 73.98 68.45 71.52N1 222 65.96 61.16 61.80N2 141 57.58 51.35 51.66N3 14 29.39 �0.01 29.68 �0.01 27.50 �0.01

S457Proceedings of the 48th Annual ASTRO Meeting