Postoperative radiotherapy for localized prostate cancer: clinical significance of nadir prostate-specific antigen value within 12 months.

AIM

To analyze retrospectively the results of postoperative radiotherapy for localized prostate cancer and to investigate the clinical significance of nadir prostate-specific antigen (PSA) value within 12 months (nPSA12) as an early estimate of clinical outcome after radiotherapy.

PATIENTS AND METHODS

Seventy-six patients with localized prostate cancer treated with postoperative radiotherapy were retrospectively reviewed. Total radiation doses ranged from 50 to 70 Gy (median: 60 Gy), and the median follow-up period for all 76 patients was 47.9 months (range, 12.4-101.3 months).

RESULTS

The 5-year actuarial overall survival, progression-free survival, biochemical relapse-free survival (BRFS) and local control rates in all 76 patients after radiotherapy were 86.1%, 77.8%, 80.0% and 92.2%, respectively. Distant metastases and/or regional lymph node metastases developed in 11 patients (14%) after radiotherapy, while local progression was observed in only 5 patients (7%). Of all 76 patients, the median nPSA12 in patients with biochemical failure and that in patients without biochemical failure were 1.16 ng/ml and 0.05 ng/ml, respectively. The 5-year BRFS rates in patients with low nPSA12 (<0.5 ng/ml) and those with high nPSA12 (> or =0.5 ng/ml) were 92.7% and 42.2%, respectively (p<0.0001). In univariate analysis, nPSA12, pre-radiotherapy PSA, Karnofsky performance status and the use of chemotherapy had a significant impact on BRFS, and in multivariate analysis, nPSA12 alone was an independent prognostic factor for BRFS.

CONCLUSION

Postoperative radiotherapy results in an excellent local control rate for localized prostate cancer and nPSA12 is predictive of biochemical failure after postoperative radiotherapy.