Comparison of Safety and Outcome Between Two Argon Plasma Coagulation Settings for Radiation Proctopathy in Patients with Prostate Cancer

Abstract

Radiation proctopathy is a late complication of radiation therapy for prostate cancer. Argon plasma coagulation (APC) is an accepted endoscopic therapy, but there is no consensus for power settings and gas flow rate. We describe our experience with two different settings. Methods: Between January, 1997 and June, 2003, 124 patients were referred for endoscopic therapy for radiation proctopathy. The first exam was always a colonoscopy to rule out synchronous lesions. Repeat procedures were sigmoidoscopies. All procedures were performed by one endoscopist using an ERBE APC 300 and ICC 200 generator with end-firing probes. Early in the series, APC settings were 75W and 1.0 L/min. Later, these settings were changed to 40-60W and 1.0 L/min. Successful outcome was defined as cessation of bleeding. Failure was determined as need for surgical or other therapy. Results: 257 procedures were performed on 114 patients (93%) with a history of prostate cancer. The mean age was 71 years (range 51-84). 44 had external beam therapy (EBT, mean dose = 6227 cGy) ± hormonal blockade (HB), 18 had EBT (mean dose = 6115 cGy) + brachytherapy (BT), and 25 patients had BT ± HB. Brachytherapy doses were set according to American Association of Physicists in Medicine Task Group #43. 28 patients had an unspecified treatment regime. The mean procedures per patient was 2.2 (range 1-7). 63 patients received at least one APC treatment session at a setting of 75W. 51 patients had APC settings of 40-60W. The 75W group required an average of 2.6 procedures (range 2-7) to achieve success as compared to 1.6 procedures (range 1-4) for the 40-60W (p<0.001). Of the 33 patients who required 3 or more treatment sessions, 27 (82%) received APC at 75W for at least one session. This subset averaged 4 treatment sessions per patient and 66.7% of these were at the 75W setting. There were 3 complications (1.2%), all in the 75W group. Two patients had continued bleeding that required admission and transfusion. One of these patients underwent a diverting colostomy. A third patient had an asymptomatic rectal stricture. Conclusions: APC is a safe and effective procedure at a power setting of 60W or less. This study underscores the need for a grading system using endoscopic findings and radiation therapy parameters to most accurately compare treatment responses.