TREATMENT OF CLINICAL LOCAL FAILURE AFTER RADIATION-THERAPY FOR PROSTATE CARCINOMA

From a base population of 634 patients with prostate cancer treated by external beam therapy with a median followup of 8 years and 123 patients treated by interstitial brachytherapy with iodine-125 (I-125) isotope with a median followup of 13 years, those with local failure only were identified. There were 57 external beam radiotherapy (9%) and 15 I-125 (12%) treated patients with local failure only among the base population. All but 3 patients (2 given external beam radiotherapy and 1 given I-125) were treated with hormonal manipulation without extirpative surgery. The overall cancer-specific median survival with hormonal therapy from the date of local failure was 70 months for 55 patients treated by external beam radiotherapy and 87 months for 14 treated by I-125. Patients with low grade, small volume tumors most likely to benefit from salvage surgery are also those who will experience prolonged survival with hormonal therapy. Patients with local failure only treated by hormonal manipulation had statistically longer cancer-specific survival rates from the date of failure than did similarly treated patients experiencing distant failure with local failure. This finding suggests a difference in the biological aggressiveness between tumors associated with distant and local failure versus local failure only. To select the patients with local failure only who would be candidates for and potentially benefited by salvage surgery, those with pretreatment stage A or B disease who were less than 72 years old were identified. A total of 17 patients treated by external beam radiotherapy and 7 treated by I-125 fulfilled these criteria. Therefore, as determined by local failure only, patient age and pre-radiation clinical stage, only 2 to 5% of the patients treated with radiation modalities are ultimately optimal candidates for salvage surgery.