LOW ACUTE GASTROINTESTINAL AND GENITOURINARY TOXICITIES IN WHOLE PELVIC IRRADIATION OF PROSTATE-CANCER

Purpose: This retrospective study was done to determine the frequency and severity of acute gastrointestinal (GI) and genitourinary (GU) tox icity associated with whole pelvic radiotherapy of localized prostate cancer. Methods and Materials: Between 1989 and 1994, we treated 156 p atients with localized prostate cancer, ranging in age from 54 to 86 ( median 71), of which 86 were older than 70 years of age. No attempt at selection was made, and many were from the Veteran's Administration H ospital where they had been precluded from their surgical program beca use of comorbidities and/or advanced age. Of 156 patients, 45 (28.8%) underwent pretreatment laparoscopic lymphadenectomy (LAP); 40 had nega tive findings. Four-held box technique was used for all patients. We t reated the whole pelvis to 45 Gy, followed by a cone-down and a final boost to a total dose of 72 Gy. The cone-down to the lower pelvis and boost to the prostate were based on computed tomography and/or magneti c resonance imaging findings for volume reconstruction with field size of approximately 8 x 8 and 6 x 6 cm, respectively. Diet instructions were given before treatment and emphasized weekly. Toxicities were eva luated weekly by physicians and nurses independently using Cancer and Leukemia Group B (CALGB) grading criteria. Results: The acute GI and G U toxicities gradually increased from Week 2, peaked at Week 5, and th en declined after that. During Week 5, acute Grade 1-3 GI morbidities were observed in 19 (12.2%),2 (1.3 %), and 1 (0.6%) patients, respecti vely. Genitourinary toxicity was similar, accounting for 17 (10.9%), 6 (3.8%), and 1 (0.6%), respectively. Overall Grade 2 toxicities occurr ed in 30 of 156 patients (19%). Comorbidity was associated with more G I toxicity. Patients over 70 years of age tended to reach the maximal GI and GU toxicity 1-2 weeks earlier than did patients under the age o f 70. Of the patients who did not follow the diet instruction, all exp erienced side effects. Conclusions: Whole pelvic irradiation was very well tolerated in this group of patients. The frequency of acute Grade 2 GI and GU toxicity compared favorably with the reported results of comformal treatment. Diet restriction and psychosocial input may have had a positive impact. Late sequelae will be evaluated in long-term fo llowup. (C) 1997 Elsevier Science Inc.