CHRONIC RECTAL BLEEDING AFTER HIGH-DOSE CONFORMAL TREATMENT OF PROSTATE-CANCER WARRANTS MODIFICATION OF EXISTING MORBIDITY SCALES

Purpose: Serious late morbidity (Grade 3/4) from the conformal treatme nt of prostate cancer has been reported in <1% to 6% of patients based on existing late gastrointestinal (GI) morbidity scales. None of the existing morbidity scales include our most frequently observed late GI complication, which is chronic rectal bleeding requiring multiple ful gerations. This communication documents the frequency of rectal bleedi ng requiring multiple fulgerations and illustrates the variation in re ported late serious GI complication rates by the selection of morbidit y scale. Methods and Materials: Between May 1989 and December 1993, 35 2 patients with T1-T3 nonmetastatic prostate cancers were treated with our four-field conformal technique without special rectal blocking. T his technique includes a 1-cm margin from the clinical target volume ( CTV) to the planning target volume (PTV) in all directions. The median follow-up for these patients was 36 months (range 2-76), and the medi an center of prostate dose was 74 Gy (range 63-81). Three morbidity sc ales are assessed: the Radiation Therapy Oncology Group (RTOG), the La te Effects Normal Tissue Task Force (LENT), and our modification of th e LENT (FC-LENT). This modification registers chronic rectal bleeding requiring at least one blood transfusion and/or more than two coagulat ions as a Grade 3 event. Estimates for Grade 3/4 late GI complication rates were determined using Kaplan-Meier methodology. The duration of severe symptoms with chronic rectal bleeding is measured from the firs t to the last transrectal coagulation. Latency is measured from the en d of radiotherapy to surgery, first blood transfusion, or third coagul ation procedure. Results: Sixteen patients developed Grade 3/4 complic ations by one of the three morbidity scales. Two patients required sur gery (colostomy or sigmoid resection), three required multiple blood t ransfusions, two required one or two blood transfusions, and nine requ ired at least three coagulations. The median duration of bleeding for those patients requiring multiple procedures was 7 months (range 3-33) and the median latency was 22 months (range 9-40). The 5-year actuari al rate of Grade 3/4 complications by each scale are: RTOG 0.7%, LENT 2%, and FC-LENT 6%. The rate of chronic rectal bleeding increases with increasing dose and is low in patients treated with conventional tech niques owing to lower doses. Conclusion: Chronic rectal bleeding requi ring any blood transfusion(s) or multiple coagulation procedures is ou r most frequently observed complication. This complication appears lat e in follow-up and is present for a long duration. We believe this jus tifies the inclusion of chronic rectal bleeding requiring multiple coa gulation procedures as a Grade 3 event in future morbidity scales. Our data illustrate that published Grade 3/4 morbidity rates are highly d ependent on the morbidity scale selected, as our data show 0.7% RTOG, 2% LENT, and 6% FC-LENT. Obviously, a uniform scale is required that i ncludes the newly recognized serious late effects associated with the conformal treatment of prostate cancer. (C) 1997 Elsevier Science Inc.