Salvage radiotherapy after radical prostatectomy: outcomes and prognostic factors especially focusing on pathological findings

Prediction of survival outcomes following postoperative radiotherapy after radical prostatectomy for prostate cancer

Background: To evaluate predictive factors for survival outcomes after post-prostatectomy radiotherapy.Material and methods: In the years 2003-2008, 324 patients have received postoperative radiotherapy a median time of 14 months after radical prostatectomy. All patients have been treated up to 66.0-66.6 Gy in 1.8-2.0 Gy fractions. Predictive factors were analyzed at two stages, using a multivariable Cox regression analysis: (1) based on factors known before radiotherapy and (2) based on prostate-specific antigen response after radiotherapy.Results: Median follow-up after radiotherapy was 121 months. Prostate-specific antigen before radiotherapy, pN1 and Gleason score remained predictive factors for disease-free (hazard ratio, HR of 6.0, 2.3 and 2.5) and overall survival (HR of 2.8, 2.0 and 1.6) in multivariable analysis. Prostate-specific antigen levels increased despite radiotherapy in 27% of patients in the first six months. Failed response following salvage radiotherapy and prostate-specific antigen doubling time at the time of biochemical recurrence were predictive factors for disease-free (HR of 2.8 and 7.3; p < .01) and overall survival (HR of 2.2 and 2.6; p < .01).Conclusion: To reach the best survival outcomes following prostatectomy, salvage radiotherapy should be initiated early with low prostate-specific antigen levels, especially in patients with higher Gleason scores. Patients not responding to radiotherapy and/or patients with a short prostate-specific antigen doubling time after radiotherapy are candidates for early additional treatments.

Radiotherapy after prostatectomy: prognosis, timing and outcomes

Biochemical disease-free survival following radical prostatectomy can be improved with the use of adjuvant and salvage radiotherapy. However, there is a lack of consensus over the ideal timing to start adjuvant and salvage radiotherapy after surgery. The literature in relation to adjuvant and salvage radiotherapy following radical prostatectomy was reviewed, focusing specifically on the prognostic factors that influence the need for postoperative radiotherapy, outcomes following adjuvant and salvage radiotherapy and potential side effects. Post-surgery prognostic factors can be useful in identifying patients early on who may benefit from adjuvant radiotherapy. While there is literature examining the role of radiotherapy following radical prostatectomy, few dedicated trials investigate this area thoroughly.

Prognostic factors after salvage radiotherapy alone in patients with biochemical recurrence after radical prostatectomy

OBJECTIVES

To evaluate the oncological outcome and to assess prognostic factors of salvage radiotherapy alone in patients with biochemical recurrence after radical prostatectomy.

METHODS

We reviewed our single institution, prospectively maintained database of 2043 patients who underwent radical prostatectomy between September 1995 and December 2011. In this cohort, 149 patients who developed biochemical recurrence after radical prostatectomy and received salvage radiotherapy alone after pelvic magnetic resonance imaging were included. Three-dimensional conformal radiotherapy or intensity-modulated radiotherapy was delivered with a median dose of 70.0 Gy (66.0-78.0 Gy) or 67.2 Gy (64.8-70.0 Gy). Kaplan-Meier and Cox regression analyses were carried out.

RESULTS

With a median follow up of 82 months (range 20-153 months), 55 patients (36.9%) failed salvage radiotherapy. The 5-year salvage radiotherapy failure-free probability was 53.6%. On multivariate analysis, pre-salvage radiotherapy prostate-specific- antigen ≥ 1.0 ng/mL (P = 0.003, hazard ratio 3.592, 95% confidence interval 1.522-8.579), pathological stage ≥ T3a (P = 0.004, hazard ratio 2.261, 95% confidence interval 1.290-3.833), pathological Gleason score ≥ 7 (P = 0.018, hazard ratio 5.501, 95% confidence interval 1.577-21.221), prostate-specific antigen doubling time < 12 months (P = 0.014, hazard ratio 2.243, 95% confidence interval 1.177-4.275) and no visible lesion on pelvic magnetic resonance imaging (P = 0.016, hazard ratio 2.068, 95% confidence interval 1.268-3.501) were independent prognostic factors of salvage radiotherapy failure after radical prostatectomy.

CONCLUSIONS

Pre-salvage radiotherapy prostate-specific antigen ≥ 1.0 ng/mL, pathological stage ≥ T3a, pathological Gleason score ≥ 7, prostate-specific antigen doubling time < 12 months and no visible lesion on pelvic magnetic resonance imaging are prognostic factors of salvage radiotherapy failure after radical prostatectomy. We should consider additional treatment in patients with these factors for favorable outcomes.

Current status and outcomes of patients developing PSA recurrence after prostatectomy who were treated with salvage radiotherapy: a JROSG surveillance study

The conditions and outcomes of Japanese patients with prostate cancer who developed PSA failure after radical prostatectomy (RP), and who were treated via salvage radiotherapy (S-RT), were surveyed. Clinical data on S-RT were gathered in questionnaires completed by facilities participating in the Japanese Radiation Oncology Study Group. S-RT was defined as external-beam radiotherapy delivered to the prostate beds of patients with prostate cancer who had eventually developed PSA failure, although their PSA values had at one stage attained levels <0.2 ng/ml following RP. Hormonal therapy was combined with S-RT in ∼40% of cases. Outcomes were evaluated in 186 cases treated via S-RT alone. The nadir PSA level after RP, and the level upon initiation of S-RT, were 0.0135 ng/ml and 0.292 ng/ml, respectively. The median period between RP and S-RT was 18.6 months. The median follow-up period was 58 months. The 5-year PSA recurrence-free survival (PRFS) and clinical failure-free survival (CFFS) rates were 50.1% (95% CI: 42.8-57.9%) and 90.1% (95% CI: 86.4-95.7%), respectively. PRFS was significantly superior in patients with PSA values ≤0.3 ng/ml upon initiation of S-RT than in those with PSA values >0.3 ng/ml (57.5% vs 40.5%, P = 0.027). In Japan, hormonal therapy is combined with S-RT in ∼40% of cases. The 5-year PRFS and CFFS rates of cases treated via S-RT alone were 50.1% and 90.1%, respectively. A PSA value of 0.3 ng/ml served as a significant cut-off for prediction of PRFS.

Significance of early prostate-specific antigen values after salvage radiotherapy in recurrent prostate cancer patients treated with surgery

OBJECTIVES

To assess the use of post-salvage radiotherapy prostate-specific antigen for early prediction of biochemical failure or clinical recurrence after salvage radiotherapy in recurrent prostate cancer patients after prostatectomy.

METHODS

From 2000 to 2011, 164 patients were treated with salvage radiotherapy alone for recurrent prostate cancer. Patients who received androgen deprivation therapy before or within 1 month of the termination of salvage radiotherapy were excluded. Survival analysis was carried out with: (i) a selected prostate-specific antigen reference value (0.2 ng/mL) at the second follow-up period (4 months) after salvage radiotherapy (prostate-specific antigen value over 0.2 ng/mL at post-salvage radiotherapy 4 months); and (ii) prostate-specific antigen percent decline (post-salvage radiotherapy 4 months prostate-specific antigen/pre-salvage radiotherapy prostate-specific antigen).

RESULTS

The median follow-up time was 53.4 months (range 8.5-134.1 months). The 5-year clinical recurrence-free survival was 87.9%. Prostate-specific antigen percent decline of 0.45 was set as the cut-off value for clinical recurrence-free survival based on the receiver operating characteristics curve. In the multivariate analysis, a prostate-specific antigen value over 0.2 ng/mL at post-salvage radiotherapy 4 months (P = 0.013) and prostate-specific antigen percent decline ≥ 0.45 (P = 0.002) were both significant parameters predicting clinical recurrence-free survival. Otherwise, prostate-specific antigen percent decline ≥ 0.45 was the only statistically significant predictor of biochemical failure-free survival (biochemical failure-free survival after salvage radiotherapy).

CONCLUSIONS

A prostate-specific antigen value over 0.2 ng/mL at post-salvage radiotherapy 4 months and prostate-specific antigen percent decline ≥ 0.45 are negative predictors of clinical recurrence-free survival after salvage radiotherapy. Prostate-specific antigen percent decline ≥ 0.45 is also associated with worse biochemical failure-free survival after salvage radiotherapy. Patients with delayed prostate-specific antigen decrease should be carefully observed for clinical recurrence.

Salvage radiotherapy after radical prostatectomy: prediction of biochemical outcomes

Introduction

A significant proportion of patients undergoing salvage radiotherapy (RT) for biochemical recurrence (BCR) following radical prostatectomy (RP) may again experience BCR after salvage RT. Thus, we evaluated the clinical significances of different parameters on the biochemical outcome of RT in salvage setting.

Methods

We reviewed the records of 212 patients who underwent salvage RT between November 2003 and December 2012 for BCR following primary RP. BCR-free survivals after salvage RT were estimated using the Kaplan–Meier method. Cox proportional hazard regression models were used to evaluate the impacts of clinicopathologic parameters on BCR following salvage RT.

Results

The overall median follow-up duration was 63.5 months. The BCR-free survival rate after salvage RT was 58.2% at 5 years. Multivariate analysis showed that a pre-RT prostate-specific antigen (PSA) level of ≤0.5 ng/mL, a pre-RT PSA doubling time (PSADT) of >4.5 months, concomitant androgen deprivation therapy (ADT) with salvage RT, and a positive surgical margin were independent predictors of favorable biochemical outcomes after salvage RT (hazard ratios [HR] = 3.012, 1.132, 2.000, and 1.805, respectively, p = less than 0.001, 0.013, 0.005, and 0.036, respectively). In the early (pre-RT PSA ≤0.5 ng/mL) salvage RT setting, concomitant ADT administration was also shown to be significantly associated with higher risk of BCR-free survival following salvage RT (HR = 2.611, p = 0.038).

Conclusion

Lower pre-RT PSA value, longer PSADT before salvage RT, concomitant ADT administration, and a positive surgical margin were significant predictors of favorable biochemical outcomes following salvage RT performed for BCR after primary RP.

Prediction of outcome following early salvage radiotherapy among patients with biochemical recurrence after radical prostatectomy

BACKGROUND

Early salvage radiotherapy (eSRT) represents the only curative option for prostate cancer patients experiencing biochemical recurrence (BCR) for local recurrence after radical prostatectomy (RP).

OBJECTIVE

To develop and internally validate a novel nomogram predicting BCR after eSRT in patients treated with RP.

DESIGN, SETTING, AND PARTICIPANTS

Using a multi-institutional cohort, 472 node-negative patients who experienced BCR after RP were identified. All patients received eSRT, defined as local radiation to the prostate and seminal vesicle bed, delivered at prostate-specific antigen (PSA) ≤ 0.5 ng/ml.

OUTCOME MEASUREMENT AND STATISTICAL ANALYSIS

BCR after eSRT was defined as two consecutive PSA values ≥ 0.2 ng/ml. Uni- and multivariable Cox regression models predicting BCR after eSRT were fitted. Regression-based coefficients were used to develop a nomogram predicting the risk of 5-yr BCR after eSRT. The discrimination of the nomogram was quantified with the Harrell concordance index and the calibration plot method. Two hundred bootstrap resamples were used for internal validation.

RESULTS AND LIMITATIONS

Mean follow-up was 58 mo (median: 48 mo). Overall, 5-yr BCR-free survival rate after eSRT was 73.4%. In univariable analyses, pathologic stage, Gleason score, and positive surgical margins were associated with the risk of BCR after eSRT (all p ≤ 0.04). These results were confirmed in multivariable analysis, where all the previously mentioned covariates as well as pre-RT PSA were significantly associated with BCR after eSRT (all p ≤ 0.04). A coefficient-based nomogram demonstrated a bootstrap-corrected discrimination of 0.74. Our study is limited by its retrospective nature and use of BCR as an end point.

CONCLUSIONS

eSRT leads to excellent cancer control in patients with BCR for presumed local failure after RP. We developed the first nomogram to predict outcome after eSRT. Our model facilitates risk stratification and patient counselling regarding the use of secondary therapy for individuals experiencing BCR after RP.

PATIENT SUMMARY

Salvage radiotherapy leads to optimal cancer control in patients who experience recurrence after radical prostatectomy. We developed a novel tool to identify the best candidates for salvage treatment and to allow selection of patients to be considered for additional forms of therapy.