Significance and treatment of positive margins or seminal vesicle invasion after radical prostatectomy. The periprostatic soft-tissue involvement described in the older urologic literature differs from that now recognized; a much "earlier" pathologic stage C is being identified. Apparent microscopic extension of the cancer to the margin of the specimen yields an approximately 25% risk of local recurrence. Postoperative radiation apparently is effective in reducing this risk, and if patients are properly selected, such treatment is well tolerated. Whether adjuvant radiation affects overall survival is not known. New observations on pathologic extension of the disease need to be refined. 