Postoperative Radiotherapy for Patients with Prostate Cancer in Japan; Changing Trends in National Practice between 1996–98 and 1999–2001: Patterns of Care Study for Prostate Cancer

Abstract

To evaluate the changing trends of standards and practices for postoperative radiotherapy (RT) for patients with prostate cancer in Japan. The Japanese Patterns of Care Study (PCS) conducted a national survey in 84 institutions from 1996 to 1998 (PCS96-98) and 76 institutions from 1999 to 2001 (PCS99-01). Detailed information relevant to RT was collected on a total of 169 patients (64 from 1996 to 1998 and 105 from 1999 to 2001) with prostate cancer who had undergone radical prostatectomy. The fraction of clinical T3-4 tumours before prostatectomy decreased from 63% in the period 1996-98 to 26% in the period 1999-2001 (P = 0.0004). The pre-RT prostate-specific antigen level was significantly lower in 1999-2001 than in 1996-98 (P = 0.0002). We did not find a significant difference in the percentage of patients who received pelvic irradiation in the time periods between PCS96-98 and PCS99-01 (P = 0.18). Although the median radiation doses of 60 Gy were not changed between the surveys, various doses (from 20 to 74.6 Gy) were delivered to the prostatic bed. In the 1999-2001 survey, 73 of 105 patients received a median dose of 56 Gy in an adjuvant setting, while the other 32 received a median dose of 60 Gy in a salvage setting (P = 0.0015). These data suggest that consensus has not been reached on the practice and management of postoperative RT for patients with prostate cancer in Japan.