RADIOSENSITIVITY OF KOCK ILEAL RESERVOIR

Purpose: To acquire preliminary information on the radiosensitivity of the Rock ileal reservoir by reviewing acute and late toxicity incurre d by nine patients who received pelvic radiotherapy after cystoprostat ectomy with lower urinary reconstruction utilizing a Koch ileal reserv oir with bilateral uretero ileal-urethrostomy. Methods and Materials: All patients were irradiated because of synchronous locally advanced p rostate cancer (pT3). A fourfield box technique at 100 cm source-axis- distance (SAD) with all fields treated every day at 1.8 Gy daily fract ions, to a total dose of 45-50.40 Gy was used. The average AP portal d imension was 11 x 11 cm, and the average lateral was 7 x 8 cm. All por tals were shaped using custom shields to optimize protection of normal tissues not suspected of tumor involvement (small bowel, posterior re ctal wall), No attempt was made to shield the Rock ileal reservoir, Fo r each patient, comparison of the treatment portals with the Kockgram radiography (gravity cystogram) confirmed the inclusion of the majorit y of the Kock ileal reservoir within the radiation fields, Acute and l ate morbidity was measured by RTOG toxicity criteria by retrospectivel y reviewing the patients' records, Results: Only mild acute toxicity w as reported by the patients: Six patients experienced grade 1 acute ur inary toxicity and one suffered Grade 2 acute urinary toxicity, In fou r patients Grade 1 acute gastrointestinal toxicity occurred and in two patients Grade 2 toxicity occurred. With a median follow-up of 50 mon ths late toxicity consisted mainly of microscopic hematuria in six pat ients and persistent frequency in two patients (with spontaneous impro vement respectively at 4 and 6 months after radiation), No patients ex perienced acute or late Grade 3 or 4 genitourinary or gastrointestinal toxicity, Conclusion: The use of moderate doses of pelvic radiotherap y (45-50.40 Gy) at standard fractionation was well tolerated among nin e patients who received pelvic radiation for invasive prostate cancer detected at the time of cystectomy and Kock ileal reservoir diversion, These preliminary data support the evidence that patients with a Kock ileal reservoir could safely undergo postoperative pelvic radiotherap y in these dose ranges and fractionation. (C) 1997 Elsevier Science In c.