Salvage external beam radiotherapy for clinical failure after cryosurgery for prostate cancer

Abstract

Purpose: To investigate the role of external beam radiotherapy (EBRT) as salvage treatment of prostate cancer after cryosurgery failure.Methods and Materials: Between 1993 and 1998, 6 patients underwent EBRT with curative intent for local recurrence of prostate cancer after cryosurgery. All 6 patients had biopsy-proven recurrence and palpable disease on digital rectal examination at the time of EBRT. The median follow-up was 34 months (range 8–46). The median prostate-specific antigen level was 2.3 ng/mL (range 0.8–4.1). No patient had evidence of metastatic disease. Two patients received hormonal therapy before beginning EBRT. No patient received hormonal therapy after EBRT completion. The median elapsed time between cryosurgery and EBRT was 3 years (range 1.5–4). The median delivered dose was 66 Gy (range 62–70.2) using a 10-MeV photon beam. An in-house-developed three-dimensional treatment planning system was used to plan delivery of the prescribed dose with conformal radiotherapy techniques.Results: After EBRT, all patients had complete resolution of palpable disease. Four patients (66%) were disease free at the time of the last follow-up. Two patients developed biochemical failure as defined by the American Society for Therapeutic Radiology and Oncology consensus definition. One of these patients had a prostate-specific antigen level of 97 ng/mL before cryosurgery. No patient developed distant metastasis during follow-up. Two patients (33%) developed proctitis; 1 case resolved with Rowasa suppositories and 1 required blood transfusion.Conclusions: Our preliminary results suggest that EBRT can render a significant number of patients biochemically free of disease and can cause complete resolution of clinically palpable disease after initial cryosurgery. The results also showed that EBRT can be given without excessive morbidity. EBRT should be considered as a treatment option in these potentially curable cases.