EXTERNAL IRRADIATION AND INTERSTITIAL BRACHYTHERAPY TWICE PER DAY FOR PROSTATE CANCER-INITIAL RESULTS

Abstract

Purpose: To evaluate the effectiveness and safety of the combination of external irradiation and interstitial brachytherapy twice per day for prostate cancer.
Materials and Methods: The cases were 42 patients with prostate cancer (4 cases in Stage A, 14 in Stage B, 20 in Stage C and 4 in Stage D) who underwent external irradiation of 50 Gy to the prostate gland including 30 Gy to the pelvis and interstitial brachytherapy of 5.5Gy×2/day in 4 cases, 7.0Gy×2/day in 2 cases and 7.5 Gy×2/day in 36 cases. The average age was 77.5 (range 61 to 89) years old.
Results: Prostate specific antigen (PSA) values after the combinated radiation therapy dropped in each case. Three cases with PSA failure were noted during the average observation term of 12 months. No cases with stage A, B or less than Gleason score 6 were associated with PSA failure. Biochemically no evidence of disease (bNED) survival curve showed significant PSA failure in the cases with PSA values of ≥30ng/ml than in those with PSA values of <30ng/ml. Transient rectal bleeding (2.3%), diarrhea (7%) and perianal pain (4.7%) as adverse effects of radiation treatment were noted.
Conclusion: Initial results of external irradiation and interstitial brachytherapy twice a day are promising especially for aged cases with early prostate cancer. However, longer-term observation is needed to evaluate the real effectiveness and the adverse effect of this combinated radiation therapy.