Outcomes and predictors of localized or locally-advanced prostate cancer treated by radiotherapy in Indonesia

Abstract

Purpose:

Presently there is no published data on the outcomes of localized or locally-advanced prostate cancer (PCa) treated by external-beam radiotherapy (RT) in Indonesia.

Methods:

This study retrospectively analyzed 96 patients with localized or locally-advanced PCa treated by RT from year 1995 to 2009, at the national referral hospital and the national cancer hospital of Indonesia. Cumulative prostate and pelvic radiation dose/type was <70 Gy conventional RT in 84.4% patients, and ≥70 Gy Three dimensional-conformal or intensity modulated RT in 15.6% patients. Overall survival (OS) and biochemical progression-free survival (BFS) were estimated by Kaplan-Meier. Predictors of OS and biochemical recurrence were analyzed by multivariate Cox regressions.

Results:

The median follow-up was 61 months (range, 24 to 169 months). There were 3.1% low-risk, 26% intermediate-risk, and 70.8% high-risk cases. More than half of the patients (52.1%) had pretreatment prostate-specific antigen (PSA) >20 ng/mL. The 5-year survival outcome of low-risk, intermediate-risk, and high-risk patients were: OS, 100%, 94.7%, and 67.9% ( P=0.297); and BFS, 100%, 94.1%, and 57.1% ( P=0.016), respectively. In the high-risk group, the 5-year OS was 88.3% in patients who received adjuvant hormonal androgen deprivation therapy (HT), compared to 53% in RT only, P=0.08. Significant predictors of OS include high-risk group (hazard Ratio [HR], 9.35; 95% confidence interval [CI], 1.52 to 57.6; P=0.016), adjuvant therapy (HR, 0.175; 95% CI, 0.05 to 0.58; P=0.005), detection by transurethral resection of the prostate (TUR-P) (HR, 6.81; 95% CI, 2.28 to 20.33; P=0.001), and pretreatment PSA (HR, 1.003; 95% CI, 1.00 to 1.005; P=0.039). The sole predictor of biochemical failure was pretreatment PSA ( P=0.04), with odds ratio of 4.52 (95% CI, 1.61 to 12.65) for PSA >20 ng/mL.

Conclusions:

RT is an effective treatment modality for localized or locally-advanced PCa in Indonesian patients, with outcomes and predictors consistent to that reported elsewhere. Predictors of poorer outcomes include high-risk group, higher pretreatment PSA, incidental detection by TUR-P, and lack of adjuvant HT. Adjuvant hormonal therapy significantly improve the survival of high risk patients.