Salvage radiation therapy for prostate cancer patients after prostatectomy

The effects of PSA kinetics on the outcome of hypofractionated salvage radiotherapy for biochemical recurrence of prostate cancer after prostatectomy

The feasibility and efficacy of hypofractionated salvage radiotherapy (HS-RT) for prostate cancer (PC) with biochemical recurrence (BR) after prostatectomy, and the usefulness of prostate-specific antigen (PSA) kinetics as a predictor of BR, were evaluated in 38 patients who received HS-RT without androgen deprivation therapy between May 2009 and January 2017. Their median age, PSA level and PSA doubling time (PSA-DT) at the start of HS-RT were 68 (53-74) years, 0.28 (0.20-0.79) ng/ml and 7.7 (2.3-38.5) months, respectively. A total dose of 60 Gy in 20 fractions (three times a week) was three-dimensionally delivered to the prostate bed. After a median follow-up of 62 (30-100) months, 19 (50%) patients developed a second BR after HS-RT, but only 1 patient died before the last follow-up. The 5-year overall survival and BR-free survival rates were 97.1 and 47.4%, respectively. Late grade 2 gastrointestinal and genitourinary morbidities were observed in 0 and 5 (13%) patients, respectively. The PSA level as well as pathological T-stage and surgical margin status were regarded as significant predictive factors for a second BR by multivariate analysis. BR developed within 6 months after HS-RT in 11 (85%) of 13 patients with a PSA-DT < 10 months compared with 1 (17%) of 6 with a PSA-DT ≥ 10 months (median time to BR: 3 vs 14 months, P < 0.05). Despite the small number of patients, our HS-RT protocol seems feasible, and PSA kinetics may be useful for predicting the risk of BR and determining the appropriate follow-up schedule.

Predicting factors for progression to castration resistance prostate cancer after biochemical recurrence in patients with clinically localized prostate cancer who underwent radical prostatectomy

BACKGROUND

To determine prognostic factors associated with progression to castration-resistant prostate cancer following biochemical recurrence which is lethal prostate cancer and establish a risk stratification model of progression to castration-resistant prostate cancer.

METHODS

We retrospectively reviewed the data of 550 patients who experienced biochemical recurrence after radical prostatectomy. The endpoint of the present study was progression to castration-resistant prostate cancer. The actuarial probabilities of progression to castration-resistant prostate cancer-free survival were determined using Kaplan-Meier analysis. Univariate and multivariate Cox proportional hazards regression analyses were used to identify independent predictors of biochemical recurrence.

RESULTS

Fifty-two patients experienced progression to castration-resistant prostate cancer during the follow-up period. The progression to castration-resistant prostate cancer-free survival rate after biochemical recurrence at 10 years was 76.8%. In multivariate analysis, pathological Gleason score ≥ 9, lymphovascular invasion, and prostate-specific antigen velocity ≥ 0.4 ng/mL/year were independent predictive factors for progression to castration-resistant prostate cancer. The patients were stratified into three groups using a risk stratification model incorporating these variables. The 10-year progression to castration-resistant prostate cancer-free survival rates were 96.7% in the low-risk group, 84.7% in the intermediate-risk group, and 24.5% in the high-risk group.

CONCLUSIONS

The present results suggest that the pathological Gleason score, lymphovascular invasion, and prostate-specific antigen velocity were independent predictive factors for progression to castration-resistant prostate cancer. The risk stratification model established in the present study could be useful for patient counseling and in identifying patients with a poor prognosis.