Survival following biochemical recurrence after radical prostatectomy and adjuvant radiotherapy in patients with prostate cancer: the impact of competing causes of mortality and patient stratification

Abstract

Background: Data regarding the natural history of biochemical recurrence (BCR) after radical prostatectomy (RP) and adjuvant radiotherapy (aRT) are limited.

Objective: To evaluate cancer-specific (CSM) and other-cause mortality (OCM) in prostate cancer patients with BCR after RP and aRT.

Design, setting, and participants: We identified 336 patients with BCR treated between 1990 and 2006 at two tertiary care centers.

Intervention: All patients underwent RP plus aRT.

Outcome measurements and statistical analysis: Cox regression analyses were used to evaluate the association between clinicopathologic variables and CSM. The coefficients of CSM-independent predictors were used to develop a novel nomogram. Patients were stratified into groups according to nomogram-calculated CSM probability and median age. Competing-risks survival analyses were used to estimate CSM and OCM for each group.

Results and limitations: Ten-year CSM and OCM were 21.5 and 21.7%, respectively. On multivariable analyses, short time to BCR, pathologic Gleason score ≥ 8, and positive lymph node count of more than two at RP were significantly associated with increased CSM rate (all p ≤ 0.01). These variables were used to develop a novel nomogram, which was used to stratify patients according to their 10-yr, nomogram-calculated, CSM probability: ≤ 10% versus >10-30% versus >30%. On competing-risks analysis, 10-yr CSM rate for these groups was 6%, 15%, and 42%, respectively, for patients aged ≤ 68 yr, versus 8%, 19%, and 42% for patients aged >68 yr. Likewise, 10-yr OCM rate was 24%, 9%, and 10%, respectively, for patients aged ≤ 68 yr, versus 37%, 20%, and 28%, respectively, for patients aged >68 yr. The study is limited by its retrospective design.

Conclusions: Short time to BCR, pathologic Gleason score ≥ 8, and more than two positive lymph nodes were independent predictors of CSM in patients with BCR after RP and aRT. Men with these features may benefit from additional secondary therapies, ideally, in a clinical trial setting.

Keywords: Adjuvant; Neoplasm recurrence; Prostatic neoplasms/mortality; Prostatic neoplasms/pathology; Prostatic neoplasms/surgery; Radiotherapy; Risk factors.