S398 I. J. Radiation Oncology d Biology d Physics Volume 69, Number 3, Supplement, 2007

Tumor characteristics

TAHBSO TAHBSO and adjuvant radiotherapy

Number

27 51

Stage

I 78% I 34%

II 11%

II 40%

III 11%

III 26%

Grade

1 33% 1 18%

2 37%

2 30%

3 30%

3 40% Unknown 2%

Pathology

Endometroid 77% Endometroid 60%

Papillary serous 15%

Papillary serous 20%

Clear cell 4% Other 4%

Clear cell 12%

Other 8%

Author Disclosure: M.A. Al refae, None; D. Roberge, None; L. Portelance, None; M. Duclos, None; L. Gilbert, None; L. Souhami,None.

2348 Tumor Volume and Uterine Body Invasion Assessed by MRI for Prediction of Outcome in Cervical

Carcinoma Treated With Concurrent Chemotherapy and Radiotherapy

H. Kim1, W. Kim2

1Department Radiation Oncology, Dongguk University Gyongju Hospital, Gyongju, Republic of Korea, 2Department RadiationOncology, Inha University Medical College, Inchon, Republic of Korea

Purpose/Objective(s): The aim of this study was to evaluate the prognostic significance of primary tumor volume and uterinebody invasion assessed by pre-treatment MRI for uterine cervical cancer patient treated by concurrent chemotherapy and radiother-apy in the presence of other more traditional prognostic factors.

Materials/Methods: A retrospective analysis of 106 patients with IB-IIIB cervical carcinoma were performed. Potential prognos-tic factors were stage, clinical tumor diameter, histology, age, pelvic lymph node, tumor volume, and uterine body invasion status.Multivariate analyses were performed to identify the prognostic factor for overall survival (OS), disease-free survival (DFS), pelviccontrol (PC), and distant metastasis-free survival (DMFS).

Results: The 5-year OS, DFS, PC, and DMFS rate were 59.7%, 56.6%, 67.4% and 77.6%, respectively. Using multivariate anal-yses, a large tumor volume ($30 mL; p = 0.029) and uterine body invasion (p = 0.004) and positive pelvic lymph node (LN) en-largement (p = 0.024) showed a significantly unfavorable influence on OS. In analysis of PC, only a larger tumor volume ($30 mL;p = 0.015) proved to be significant and only uterine body invasion were shown to be independently related to DMFS in the presenceof the other factor (p = 0.028). Using these three factors, patients were divided into four subgroups: the OS rates of patients with risk0 (volume\30 mL, no uterine body invasion, and negative LN), risk 1 (one of these three factors), risk 2 (two of these three fac-tors), and risk 3 (volume $30 mL, uterine body invasion, and positive LN) were 96.3%, 77.5%, 53.0%, and 14.8%, respectively(p \ 0.0001).

Conclusions: Tumor volume and uterine body invasion determined by MRI were significant prognostic factors for patients withcervical carcinoma. Pelvic lymph node enlargement diagnosed by CT also provided to be a significant prognostic factor in OS.Using these three parameter, we devised a practical and effective model to predict OS.

Author Disclosure: H. Kim, None; W. Kim, None.

2349 Intensity-Modulated Whole Pelvic Radiotherapy (IM-WPRT) for Intact Cervical Cancer: Comparison

With Conformal 4-Field WPRT and Sensitivity of Organ Sparing Effect to Margin Size

R. Y. Kim, H. McCarty, J. Caudell, R. Popple, S. Shen, J. Duan

University of Alabama Medical Center, Birmingham, AL

Purpose/Objective(s): Numerous dosimetric and a few toxicity studies have demonstrated the superiority of IM-WPRT for ad-juvant radiotherapy after hysterectomy compared to conformal 4-field WPRT. After hysterectomy, the pelvis often contains a sig-nificant portion of the bowel. IM-WPRT can significantly reduce the dose to adjacent critical structures. However, the benefit ofIM-WPRT in patients with intact uterine cancer is less well defined due to uncertainties of target definition, internal organ motion,and target changes during the course of treatment. This dosimetric study examines the influence of target volume expansion on thereduction of dose to surrounding structures achieved with IMRT versus standard conformal 4-field WPRT.

Materials/Methods: Clinical target volumes (CTVs) for both the primary CTV and the nodal CTV were contoured on the planningCT and/or MRI for eight patients treated with definitive WPRT for cervical cancer. The bladder, rectum and bowel (OARs) werealso contoured. The primary CTV included the gross tumor, parametria, upper vagina and the entire uterus. To account for internalmotion, the margin was added to form an initial planning target volume (PTVA) as follows: 5 mm were added to the nodal CTV and10 mm were added to the primary CTV. Two further PTVs (PTVB, PTVC) were produced by a 5 mm nodal/10 mm primary ex-pansion to give PTVB and further 5 mm/10 mm expansion to give PTVC. Treatment plans for each of the three PTVs were gen-erated by use of conformal 4-field WPRT or 7- field IMRT to deliver 45 Gy to 95% of the PTVs. We developed the IMRT plansusing target conformality as an objective. Organ sparing, particularly as it related to PTV margin size, was assessed by comparisonof dose volume histograms.