Embed Size (px)
Citation preview
Proceedings of the 50th Annual ASTRO Meeting S373
on sigmoidoscopy in 95%, 38% and 8% of the patients, respectively. Response rates of steroid enema, APC, HBOT and colostomywere 38/55 (69%), 30/34 (88%), 7/7 (100%) and 3/3 (100%), respectively.
Conclusions: Radiation proctitis shows a characteristic natural history. Interestingly, the majority of patients developing radiationproctitis receive rectal point doses within tolerance. This questions the appropriateness of the ICRU rectal point dose as a predictor ofradiation proctitis and/or the safe dose limit for rectal toxicity. CRP responds to a variety of clinical interventions. However a pro-spective systematic evaluation of several of these modalities is required to better characterize their role in this important condition.
Author Disclosure: R. Engineer, None.
2454 Let us not Conflate Newer with Better: Lack of Progress over the Past 24 Years with Primary Radiotherapy
for Stage I-II Cervix CancerT. J. Galloway1, R. J. Amdur1, C. G. Morris1, L. S. Morgan2, W. M. Mendenhall1
1University of Florida Department of Radiation Oncology, Shands Cancer Center, Gainesville, FL, 2Department of Obstetricsand Gynecology, University of Florida College of Medicine, Gainesville, FL
Purpose/Objective(s): To compare the outcomes of patients treated with primary radiotherapy for stage IB1-IIB cervix cancer ata single institution over an early (1980-1992) and late (1992-2004) treatment era.
Materials/Methods: We retrospectively reviewed the charts of 191 patients treated with radiotherapy with curative intent at theUniversity of Florida from 1980 - 2004 for stage IB1 (36 patients), IB2 (46 patients), IIA (15 patients), and IIB (94 patients) car-cinoma of the cervix. The basic treatment philosophy has been the same over this 24 year period but the quality of imaging andsophistication of radiotherapy equipment has increased with time. We used univariate and multivariate analysis to compare therates of pelvic control, relapse free survival, and grade 3-5 toxicity between treatment eras.
Results: This is a long-term follow-up series with median follow-up of 6 years for surviving patients. There was no meaningfuldifference in either relapse free survival (61% vs. 63%, p = 0.4) or local-regional control (p = 0.3) with respect to treatment era. Latetreatment complications were rare (8% among the population as a whole) and not statistically different among treatment groups.Overall, the 5-year estimates of pelvic control, local-regional control, relapse-free survival and overall survival were 80%, 74%,67%, and 61%, respectively.
Conclusions: Despite a major increase in the complexity and cost of all aspects of the process for planning and delivering radio-therapy for cervix cancer, there was no significant improvement in outcome over the past 24 years at our institution. This finding hasimportant implications for radiotherapy practice and research.
Author Disclosure: T.J. Galloway, None; R.J. Amdur, None; C.G. Morris, None; L.S. Morgan, None; W.M. Mendenhall, None.
2455 Method of Tumor Volume Evaluation using Magnetic Resonance Imaging for Outcome Prediction in
Cervical Cancer Treated with Concurrent Chemotherapy and RadiotherapyH. Kim, W. Kim
Department of Radiation Oncology, Inha University Hospital, Inha University School of Medicine, Inchon, Republic of Korea
Purpose/Objective(s): The purpose of this study was to evaluate the patterns and distribution of tumor shape and to compare tu-mor volume derived from simple diameter-based ellipsoid measurement with that derived from tracing the entire tumor contourmorphology using more complex region-of-interest (ROI)-based 3 D volumetry with respect to the prediction outcome in cervicalcancer patients treated with concurrent radio-chemotherapy.
Materials/Methods: An MRI examination was performed in 98 patients with cervical cancer (stage IB-IIIB) before the start oftreatment. The reviewer classified the tumor configuration into two categories: ellipsoid and non-ellipsoid shape. An ROI-basedvolumetry was derived in each MR slice on the computer work station. For the diameter-based surrogate ‘‘ellipsoid volume,’’the three orthogonal diameters (Dap, Dcc, and Dl) were measured to calculate volume as an ellipsoid (Dap�Dcc�Dl�p/6). Tumorvolume determined by each methods were correlated with disease-free (DFS) and overall survival (OS) and the results were com-pared between the two measuring methods.
Results: The more than half of tumor (55.1%) had a non-ellipsoid configuration. The predictions for outcome were consistent be-tween two volume groups, with OS of 93.6% and 87.7% for small tumor (\20 ml), 62.9% and 69.1% for intermediate-size tumor(20-39 ml), and 14.5% and 16.7% for large tumors ($40 ml) using ROI and diameter based measurement, respectively. DFS were93.8% and 90.6% for small tumor, 54.3% and 62.7% for intermediate-size tumor, and 13.7% and 10.3% for large tumor using ROIand diameter based method, respectively. Differences in outcome between size groups were statistically significant, and the dif-ferences in outcome predicted by the tumor volume by two different methods.
Conclusions: Our data suggested that large numbers of cervical cancers are not ellipsoid in configuration. In spite of that, simplediameter-based tumor volume measurement appears to be equivalent to ROI-based volumetry for predicting outcome in cervicalcancer patient treated with concurrent radio-chemotherapy.
Author Disclosure: H. Kim, None; W. Kim, None.
2456 Factors Affecting ICRU Point Dose and 3-D Volume Dose for Organs at Risk in Image-based Intracavitary
Brachytherapy Planning for Cervical CancerR. Kim, S. Shen, J. De Los Santos, S. Spencer
University of Alabama Medical Center, Birmingham, AL
Purpose/Objective(s): To investigate factors affecting ICRU point dose and 3-D volume dose for organs at risk (OARs).
Materials/Methods: Thirteen patients with cancer of the cervix (1 IB1, 1 IB2, 3 IIA, 5 IIB, 3 IIIB) were treated with HDR bra-chytherapy (800 cGy/fraction) by standard radiography-based treatment planning and underwent post-implant pelvic CT scans
