S640 I. J. Radiation Oncology d Biology d Physics Volume 75, Number 3, Supplement, 2009

differences could also be seen in patients that lose significant amounts of weight, specifically with changes in neck andcheek fat.

Conclusions: Weekly dose recalculation and dose difference color-coded maps represent a time-efficient dose review process. Thisprovides an unprecedented level of quality assurance based on treatment dose-of-the-day information. With further testing and val-idation of the elastic registration on MVCBCT images, dose accumulation will be feasible and further studies of dose response andtreatment efficiency can be performed.

Author Disclosure: J. Pouliot, Research supported by Siemens, C. Other Research Support; W. Hu, None; J. Cheung, None; T.Boettger, Siemens, A. Employment; S. Yom, None.

3021 Retrospective Review of Temporal Lobe Necrosis Following IMRT for Nasopharyngeal Carcinoma

E. A. Millican, J. K. Schwarz, W. L. Thorstad

Washington University School of Medicine, St Louis, MO

Purpose/Objective(s): Investigate the incidence and patient characteristics associated with temporal lobe necrosis in patientstreated with IMRT for nasopharyngeal carcinoma.

Materials/Methods: Between June 1997 and December 2008, 38 patients were treated at Washington University in St. Louis withIMRT for nasopharyngeal carcinoma. The mean patient age was 49 (range 18-86). All patients had biopsy confirmed nasopharyn-geal carcinoma with clinical stages of I (2 patients), IIB (5), III (6), IVA (17) and IVB (8). Radiation dose was 6800 to 7326 cGy in 5weekly 180 to 220 cGy fractions. 26 patients (68%) also received doses of 5610 to 6300 cGy in 154 to 180 cGy fractions to low-riskregions. All patients with stage II or greater also received chemotherapy. In radiotherapy planning, the brainstem, optic nerves,chiasm, and spinal cord were given priority over the tumor PTV. Although the adjacent brain dose was minimized, it was not givenpriority over the PTV goal of 95% coverage of the 93% isodose line. Adjacent to critical structures, including the brain, the GTV toCTV margin was reduced to 1mm, as was the CTV to PTV margin. Patients were followed clinically per institutional guidelines,including post-treatment head and neck CT or MRI. Time to adverse event estimates were performed using the Kaplan-MeierMethod.

Results: All patients completed radiation therapy with a median treatment duration of 7.5 weeks (6.3-11.4). The medianfollow-up was 38 months. Local and regional control was 100% and 95%, respectively. 10 patients (26%) died, 7 due todistant metastases, 1 from an unrelated cause, and 2 from unknown causes. 4 patients (11%) developed radiographic evi-dence of temporal lobe necrosis after a median interval of 27 months (range 7-36). Only one patient was symptomatic,with mild confusion, short-term memory loss, and a partial productive aphasia. These 4 patients all had T3-T4, IVA orIVB lesions, received concurrent chemotherapy, and 3 of the 4 were treated with daily fractions of 212 cGy to CTV1.All are followed by a neurosurgeon, but no surgical intervention has yet been required. Possibly due to small patient samplesize, there were no statistically significant differences between these four patients and the 34 patients without temporal lobenecrosis - including differences in mean dose, daily fraction dose, T stage, treatment duration, or use of concurrent chemo-therapy.

Conclusions: This retrospective review of IMRT for nasopharyngeal carcinoma in 38 patients, similar to other reviews, demon-strates excellent local and regional control. However, temporal lobe necrosis has emerged in 11% of the patients. Patient charac-teristics specifically associated with this risk could not be identified in this cohort. Trade offs in the planning process between localcontrol and complication risk remains critical in the IMRT era.

Author Disclosure: E.A. Millican, None; J.K. Schwarz, None; W.L. Thorstad, None.

3022 Post-operative Pelvic Intensity Modulated Radiation Therapy (IMRT) with Chemotherapy for Patients

with Cervical Carcinoma/RTOG 0418 Phase II Study

L. Portelance1, K. Winter2, A. Jhingran3, B. E. Miller4, M. R. Salehpour3, D. P. D’Souza5, M. G. Haddock6, M. Rotman7,D. K. Gaffney8

1McGill University Health Center, Montreal, QC, Canada, 2Radiation Therapy Oncology Group, Philadelphia, PA, 3M.D.Anderson Cancer Center, Houston, TX, 4Wake Forest Univ. Baptist Medical Center, Winston-Salem, NC, 5London HealthSciences Center, London, ON, Canada, 6Mayo Clinic, Rochester, MN, 7SUNY Health Science Center Brooklyn, Brooklyn, NY,8Huntsman Cancer Hospital, South Lake City, UT

Purpose/Objective(s): The purpose of this study was to determine the transportability of post-operative pelvic IMRT planning forpatients with cervical carcinoma in a multi institutional setting and to test the hypothesis as a secondary endpoint that there is a re-duction in short term bowel injury when pelvic IMRT is compared to standard treatment.

Materials/Methods: Patients with cervical cancer who underwent surgery with negative resection margin and who required ad-juvant chemo-radiation therapy were eligible. The target volume definition and guidelines for volume delineation, dose prescrip-tion, and dose/volume constraints for the critical structures were detailed in the study protocol. An adjoining web-based atlas wasdeveloped as well to guide the investigators. The dose to the nodal planning treatment volume (PTV) and vaginal PTV were 50.4Gy in 28 fractions. All patients also received weekly Cis-Platinum. All patients’ treatment plans were reviewed centrally. The pri-mary endpoint of this study is to define the reproducibility of the radiation technique when used in a multicenter setting. If\5 of 42treatments plans are scored unacceptable, the technique will be determined to be reproducible and considered for further study. Asecondary endpoint is to determine if this technique is associated with a reduction in grade 2 or more short-term (within 90 days)bowel AEs.

Results: 48 patients from 25 institutions were entered in the trial. Of these 40 were eligible for analysis. Of these, 33 cases wereevaluable for IMRT treatment and 7 are pending. Stages: Stage 1A 1 (3%), 1B 29 (73%), IIA 4 (10%), IIB 2 (5%), IIIB 4 (10%). Forthe PTV nodal 20 (61%) of the contours were per protocol and 13 (39%) within acceptable variation. For the vaginal PTV, 16 (48%)were per protocol and 17 (52%) were within acceptable variation. No PTV nodal or vaginal PTV plans were scored as unacceptable.