LATE GI AND GU COMPLICATIONS IN THE TREATMENT OF PROSTATE-CANCER

Purpose: To assess the factors that predict late GI and GU morbidity i n radiation treatment of the prostate. Methods and Materials: Seven hu ndred twelve consecutive prostate cancer patients treated at this inst itution between 1986 and 1994 (inclusive) with conformal or convention al techniques were included in the analysis, Patients had at least 3 m onths follow-up and received at least 65 Gy, Late GI Grade 3 morbidity was rectal bleeding (requiring three or more procedures) or proctitis , Late Grade 3 GU morbidity was cystitis or stricture, Multivariate an alysis (MVA) was used to assess factors related to the complication-fr ee survival, The factors assessed were age, occurrence of side effects greater than or equal to Grade 2 during treatment, irradiated volume parameters (use of pelvic fields, treatment of seminal vesicles to ful l dose or 57 Gy, and use of additional rectal shielding), dose, comorb idities, and other treatments (hormonal manipulation, TURP). Results: Acute GI and GU side effects (Grade 2 or higher) were noted in 246 and 201 patients, respectively; 67 of these patients exhibited both. GI s ide effects were not correlated with GU side effects acutely, Late and acute morbidities were correlated (both GI and GU), Fifteen of the 71 2 patients expressed Grade 3 or 4 GI injuries 3 to 32 months after the end of treatment, with a mean of 14.3 months, One hundred fifteen pat ients expressed Grade 2 or higher GI morbidity (mean: 13.7 months), Th e 43 Grade 2 or higher GU morbidities occurred significantly later (me an: 22.7 months), Central axis dose was the only independent variable significantly related to the incidence of late GI morbidity on MVA, No treatment volume parameters were significant for Grade 3, The followi ng parameters were significantly related (by MVA) to Grade 2 GI morbid ity: central axis dose, use of the increased rectal shielding, androge n deprivation therapy starting before RT, Acute and late GI morbiditie s were highly correlated, History of diabetes, treatment of pelvic nod es, and age less than 60 Sears were significantly related to acute GI side effects, The parameters significantly related to late Grade 2 or higher GU morbidity were central axis dose, androgen deprivation thera py (Zoladex or Lupron) prior to radiation therapy (RT), history of obs tructive symptoms, and acute GU side effects, There were too few late Grade 3 GU morbidities to perform multivariate analysis, Acute GU side effects were highly correlated with late GU injury, The following wer e correlated with acute GU side effects: history of diabetes (+), trea tment with conformal fields (-), TURF before RT (-), presentation with urinary obstructive symptoms, Conclusion: Both late GI and GU morbidi ty demonstrate a dose dependence, but only the volume dependence obser ved is a reduction in late Grade 2-4 GI morbidity by increasing the re ctal shielding in the lateral fields for the final 10 Gy, Moreover, bo th late GI and GU morbidity was increased in patients treated with hor mone manipulation prior to RT, GI and GU injuries were correlated with their corresponding acute side effects, GI and GU complications must not be combined for analysis to determine the factors related to their occurrence. Copyright (C) 1997 Elsevier Science Inc.