Interstitial radiation: short-term palliation or curative therapy?
The management of clinically localized prostatic cancer by interstitial implantation of 125I seeds has been under exploration at Memorial Sloan-Kettering Cancer Center for thirteen years. This investigation was prompted by clinical evidence of the radioresponsiveness of some prostatic cancers, the limited applicability of surgical excision, and the possibility that interstitial therapy would have less of an adverse effect on the quality of life than would alternative treatments. Cumulative experience indicates that the technique is associated with low morbidity and mortality and high functional preservation rates; local control rates (routine biopsies were not done), within the constraints of still-limited follow-up intervals, are in the 80 per cent to 90 per cent range; and actuarial survival rates at nine years (including patients who received endocrine therapy for metastatic or intractable local disease) are approximately 90 per cent for T1, 60 per cent for T2, and 45 per cent for T3 lesions. Approximate actuarial nine-year survival rates are 80 per cent for all patients with negative nodes and 50 per cent for all patients with positive nodes. Taking into account limitations of the data and the hazards of comparing this therapy with other uncontrolled treatments, 125I appears to be a therapeutic option for the control of clinically localized prostatic cancer.