125Iodine implantation for carcinoma of the prostate: 5-year survival free of disease and incidence of local failure.

Interstitial implantation with the 125iodine isotope has been used as definitive treatment in 115 patients with localized carcinoma of the prostate. The disease was staged surgically by bilateral pelvic lymphadenectomy in all of the patients. Followup has been for a minimum of 1 year and 64 patients have been followed for a minimum of 5 years. There has been no operative mortality in this series. Mean patient age at implantation was 63 years. Potency has been maintained in 31 of 46 patients (78 per cent) followed for a minimum of 5 years and 15 of 26 (58 per cent) followed for a minimum of 7 years. At 5 years the actuarial survival free of disease by surgical stage was 100, 81, 49 and 41 per cent for patients with stages A2, B, C and D1 disease, respectively. All 7 patients with stage B1 nodules followed to 5 years are free of disease. The actuarial survival free of disease by grade at 5 years was 95 per cent for patients with well, 65 per cent with moderately and 34 per cent with poorly differentiated tumors. Local failure was defined as palpable evidence of prostatic enlargement or irregularity with biopsy confirmation of neoplasm. Patients with positive biopsy plus normal or stable prostatic examinations were not considered local failures, although such patients are at high risk for failure in the future. The actuarial probability of local failure at 5 years was 0, 13, 27 and 44 per cent for patients with surgical stages A2, B, C and D1 disease, respectively, and 5, 23 and 43 per cent for those with well, moderately and poorly differentiated tumors, respectively. Based on our experience, interstitial implantation with 125iodine isotope is reserved for patients with well or moderately differentiated stage B lesions. The ultimate success of this treatment modality awaits 10 and 15 years of followup.