Prostate-specific antigen after salvage radiotherapy for postprostatectomy biochemical recurrence predicts long-term outcome including overall survival

Association between preradiation therapy prostate-specific antigen levels and radiation therapy failure after prostatectomy: a propensity score matched analysis

Purpose

We sought to determine the association between the pre-radiation therapy prostate-specific antigen (pre-RT PSA) 0.5 and RT failure in post-radical prostatectomy (post-RP) patients. Our study also investigated the prognostic factors for the failure of RT given concurrently with hormone therapy (HT) after RP.

Materials and methods

We retrospectively reviewed our institutional RP data from July 2004 to November 2021. Patients without concurrent hormone therapy were excluded. Propensity score matching was performed. Kaplan-Meier (KM) curve analysis was employed for RT failure-free survival, overall survival (OS), and cancer-specific survival (CSS). Cox regression analysis was used for the RT failure hazard ratio (HR).

Results

After propensity score matching, 193 patients were assigned to the pre-RT PSA ≥0.5 (high-P) arm, and 193 patients were assigned to the pre-RT PSA <0.5 (low-P) arm. There were no significant differences between the two arms after propensity score matching in terms of baseline characteristics and pathologic outcomes. High-P was associated with RT failure-free survival (P = 0.004), OS (P = 0.046), and CSS (P = 0.027). In a multi-variable Cox proportional hazards regression analysis, seminal vesicle invasion, lymph node invasion, the absence of prostatic intraepithelial neoplasia (PIN), and high-P were identified as significant risk factors for RT failure.

Conclusion

High-P was significantly unfavorable with RT failure-free survival, OS, and CSS in patients who underwent RT after radical prostatectomy with concurrent HT. Seminal vesicle invasion, lymph node invasion, and the absence of PIN were identified as significant prognostic factors for RT failure.

European association of urology risk stratification predicts outcome in patients receiving PSMA-PET-planned salvage radiotherapy for biochemical recurrence following radical prostatectomy

PURPOSE

The European Association of Urology (EAU) proposed a risk stratification (high vs. low risk) for patients with biochemical recurrence (BR) following radical prostatectomy (RP). Here we investigated whether this stratification accurately predicts outcome, particularly in patients staged with PSMA-PET.

METHODS

For this study, we used a retrospective database including 1222 PSMA-PET-staged prostate cancer patients who were treated with salvage radiotherapy (SRT) for BR, at 11 centers in 5 countries. Patients with lymph node metastases (pN1 or cN1) or unclear EAU risk group were excluded. The remaining cohort comprised 526 patients, including 132 low-risk and 394 high-risk patients.

RESULTS

The median follow-up time after SRT was 31.0 months. The 3-year biochemical progression-free survival (BPFS) was 85.7 % in EAU low-risk versus 69.4 % in high-risk patients (p = 0.002). The 3-year metastasis-free survival (MFS) was 94.4 % in low-risk versus 87.6 % in high-risk patients (p = 0.005). The 3-year overall survival (OS) was 99.0 % in low-risk versus 99.6 % in high-risk patients (p = 0.925). In multivariate analysis, EAU risk group remained a statistically significant predictor of BPFS (p = 0.003, HR 2.022, 95 % CI 1.262-3.239) and MFS (p = 0.013, HR 2.986, 95 % CI 1.262-7.058).

CONCLUSION

Our data support the EAU risk group definition. EAU risk grouping for BCR reliably predicted outcome in patients staged lymph node-negative after RP and with PSMA-PET before SRT. To our knowledge, this is the first study validating the EAU risk grouping in patients treated with PSMA-PET-planned SRT.

Radiotherapy after radical prostatectomy for prostate cancer: clinical outcomes and factors influencing biochemical recurrence

BACKGROUND

Radiotherapy (RT) after radical prostatectomy (RP) includes adjuvant radiotherapy (ART) and salvage radiotherapy (SRT), which can prevent or cure biochemical recurrence.

AIMS

To evaluate long-term outcomes of RT after RP and to examine factors affecting biochemical recurrence-free survival (bRFS).

METHODS

Sixty-six received ART and 73 received SRT between 2005 and 2012 were included. The clinical outcomes and late toxicities were evaluated. Univariate and multivariate analyses were performed to examine factors affecting bRFS.

RESULTS

Median follow-up from RP was 111 months. Five-year bRFS and 10-year distant metastasis-free survival from RP were 82.8% and 84.5% in ART, and 74.6% and 92.4% in SRT, respectively. The most frequent late toxicity was hematuria, which was higher in ART (p = .01). No recurrence within RT field was occurred. On univariate analysis, pelvic RT was associated with favorable bRFS in ART (p = .048). In SRT, post-RP prostate-specific antigen (PSA) level (< 0.05 ng/mL), PSA nadir after RT (≤ 0.01 ng/mL), and time to PSA nadir (≥ 10 months) were associated with favorable bRFS (p = .03, p < .001, and p = .002, respectively). On multivariate analysis, post-RP PSA level and time to PSA nadir were independent predictive factors for bRFS in SRT (p = .04 and p = .005).

CONCLUSIONS

ART and SRT had favorable outcomes with no recurrence within RT field. In SRT, the time to PSA nadir after RT (≥ 10 months) was found to be a new predictor for favorable bRFS and useful in assessing treatment efficacy.

Postoperative Radiotherapy of Prostate Cancer: Adjuvant versus Early Salvage

Results of three randomized clinical trials (RCTs) comparing adjuvant radiotherapy (ART) and early salvage radiotherapy (eSRT) of prostate carcinoma and a subsequent meta-analysis of the individual patient data from these RCTs were recently published. The results suggest that early eSRT is as effective and potentially less toxic than ART. Therefore, eSRT should be considered the standard of care. However, due to limitations in the RCTs, ART remains a valid treatment option in patients with the combination of high-risk features such as Gleason Score (GS) 8–10, positive surgical margins (R1) and pathological T-stage 3 or 4 (pT3/4). This article provides a critical appraisal of the RCTs and the rationale for recommendations adopted in the current national guidelines regarding patients with high-risk features after radical prostatectomy (RP): ART should be offered in case of pT3/pT4 and R1 and Gleason Score 8–10; ART can be offered in case of pT3/pT4 and R0 and Gleason Score 8–10 as well as in case of multifocal R1 (including pT2) and Gleason Score 8–10. In any case, the alternative treatment option of eSRT in case of rising PSA should be discussed with the patient.

Management of Biochemical Recurrence of Prostate Cancer After Curative Treatment: A Focus on Older Patients

Following a treatment with curative intent, a biochemical recurrence may be diagnosed, often many years after the primary treatment. The consequences of this relapse on survival are very heterogeneous. The expected specific survival at relapse is above 50% at 10 years. Therefore, its management needs to be balanced with the individual life expectancy. The relapse needs to be categorized as either a low- or high-risk category. The latter has to be considered for salvage therapy, provided the individual life expectancy is long enough. It is evaluated through an initial geriatric assessment, starting with the G8 score as well as the mini-Cog. A comprehensive geriatric assessment might be needed based on the G8 score. Patients will then be categorized as either fit, vulnerable, or frail. If a local salvage therapy is considered, the relapse localization might be of interest in some situations. Available salvage therapies in senior adults have nothing special compared to salvage of younger men, except for aggressive local therapy, which might be less well tolerated. The key objective in managing a biochemical recurrence in senior adults is to find the right balance between under- and over-treatment in a shared decision process. In many frail and vulnerable men, a clinically oriented watchful waiting should be preferred, while fit men with an aggressive relapse and a significant life expectancy need an active therapy.

Clinicopathological and oncological significance of persistent prostate-specific antigen after radical prostatectomy: A systematic review and meta-analysis

Objective

To investigate the association of persistently elevated prostate-specific antigen (PSA) after radical prostatectomy (RP) with clinicopathological features and long-term oncological prognosis for the development of a potential management strategy.

Methods

A systematic literature search was performed using PubMed and Web of Science up to June 2021 to identify the eligible studies focusing on understanding the impact of persistent PSA in patients who underwent RP for localized prostate cancer. Meta-analyses were performed on parameters with available information.

Results

A total of 32 RP studies were identified, of which 11 included 26 719 patients with consecutive cohorts and the remaining 21 comprised 24 177 patients with cohorts carrying specific restrictions. Of the 11 studies with consecutive cohorts, the incidence of persistent PSA varied between 3.1% and 34.6% with a median of 11.0%. Meta-analyses revealed patients with persistent PSA consistently showed unfavorable clinicopathological features and a more than 3.5-fold risk of poorer biochemical recurrence, metastasis, and prostate cancer-specific mortality prognosis independently, when compared to patients with undetectable PSA. Similarly, cases with persistent PSA in different specific patient cohorts with a higher risk of prostate cancer also showed a trend of worse outcomes.

Conclusion

We found that the frequency of persistent PSA was about 11.0% in consecutive RP cohorts. Persistent PSA was significantly associated with unfavorable clinicopathological characteristics and worse oncological outcomes. Patients with persistent PSA after RP may benefit from early salvage treatment to delay or prevent biochemical recurrence, improving oncological outcomes for these patients. Further prospective randomized controlled trials are warranted to understand optimal systemic therapy in these patients.

Impact of Dose Escalation on the Efficacy of Salvage Radiotherapy for Recurrent Prostate Cancer-A Risk-Adjusted, Matched-Pair Analysis

Previous randomized trials have not provided conclusive evidence about dose escalations and associated toxicities for salvage radiotherapy (SRT) in prostate cancer. Here, we retrospectively analyzed whether dose escalations influenced progression-free survival in 554 patients that received salvage radiotherapy for relapses or persistently elevated prostate cancer antigen (PSA) after a radical prostatectomy. Patients received SRT between 1997 and 2017 at two University Hospitals in Germany. We compared patient groups that received radiation doses <7000 cGy (n = 225) or ≥7000 cGy (n = 329) to analyze the influence of radiation dose on progression-free survival. In a second matched-pair analysis of 216 pairs, we evaluated prognostic factors (pT2 vs. pT3−4, Gleason score [GS] ≤ 7 vs. GS ≥ 8, R0 vs. R1, and pre-SRT PSA <0.5 vs. ≥0.5 ng/mL). After a median follow-up of 6.8 (4.2−9.2) years, we found that escalated doses significantly improved progression-free survival (p = 0.0042). A multivariate analysis indicated that an escalated dose, lower tumor stages (pT2 vs. pT3/4), and lower GSs (≤7 vs. 8−10) were associated with improved progression-free survival. There was no significant effect on overall survival. Our data suggested that escalating the radiation dose to ≥7000 cGy for SRT after a prostatectomy significantly improved progression-free survival. Longer follow-ups are needed for a comprehensive recommendation.

A Multi-Institutional Analysis of Prostate Cancer Patients With or Without 68Ga-PSMA PET/CT Prior to Salvage Radiotherapy of the Prostatic Fossa

Introduction

68Ga-PSMA PET/CT is associated with unprecedented sensitivity for localization of biochemically recurrent prostate cancer at low PSA levels prior to radiotherapy. Aim of the present analysis is to examine whether patients undergoing postoperative, salvage radiotherapy (sRT) of the prostatic fossa with no known nodal or distant metastases on conventional imaging (CT and/or MRI) and on positron emission tomography/computed tomography (68Ga-PSMA PET/CT) will have an improved biochemical recurrence-free survival (BRFS) compared to patients with no known nodal or distant metastases on conventional imaging only.

Material and Methods

This retrospective analysis is based on 459 patients (95 with and 364 without 68Ga-PSMA PET/CT). BRFS (PSA < post-sRT Nadir + 0.2 ng/ml) was the primary study endpoint. This was first analysed by Kaplan-Meier and uni- and multivariate Cox regression analysis for the entire cohort and then again after matched-pair analysis using tumor stage, Gleason score, PSA at time of sRT and radiation dose as matching parameters.

Results

Median follow-up was 77.5 months for patients without and 33 months for patients with 68Ga-PSMA PET/CT. For the entire cohort, tumor stage (pT2 vs. pT3-4; p= <0.001), Gleason score (GS ≤ 7 vs. GS8-10; p=0.003), pre-sRT PSA (<0.5 vs. ≥0.5ng/ml; p<0.001) and sRT dose (<70 vs. ≥70Gy; p<0.001) were the only factors significantly associated with improved BRFS. This was not seen for the use of 68Ga-PSMA PET/CT prior to sRT (p=0.789). Matched-pair analysis consisted of 95 pairs of PCa patients with or without PET/CT and no significant difference in BRFS based on the use of PET/CT was evident (p=0.884).

Conclusion

This analysis did not show an improvement in BRFS using 68Ga-PSMA PET/CT prior to sRT neither for the entire cohort nor after matched-pair analysis after excluding patients with PET-positive lymph node or distant metastases a priori. As no improved BRFS resulted with implementation of 68Ga-PSMA PET in sRT planning, sRT should not be deferred until the best "diagnostic window" for 68Ga-PSMA PET/CT.

Lead-time bias does not falsify the efficacy of early salvage radiotherapy for recurrent prostate cancer

BACKGROUND

In prostate cancer (PCa) recurring after radical prostatectomy (RP), salvage radiotherapy (SRT) is recommended to be given at PSA <0.5 ng/ml. It has been speculated, that the advantage from early SRT is mainly caused by lead-time bias: Calculating from time of SRT, earlier treatment would per-se result in longer time to event/censoring compared with later treatment, but not extend the interval from RP to post-SRT failure.

METHODS

In 603 consecutive PCa patients receiving SRT between 1997 and 2017, we compared outcomes, calculating from time of irradiation vs. time of surgery.

RESULTS

In multivariable analysis, tumor stage pT3-4, pathological Gleason score GS ≤6 vs. GS 7 vs. GS ≥8, post-RP PSA persistence (nadir ≥0.1 ng/ml), and the pre-SRT PSA (continuous or with cutoff 0.4 ng/ml) were significant risk-factors for biochemical progression (BCR) and progression-free survival (PFS) post-SRT and post-RP. A pre-SRT PSA <0.4 ng/ml was a significant discriminator for Kaplan-Meier rates of BCR and PFS. The Cox model for overall survival (OS) included age at RP (continuous), pT2 vs. pT3-4, and pre-SRT PSA (continuous) as significant predictors. However, no significant cutoff for the pre-SRT PSA could be identified to differentiate Kaplan-Meier estimates of OS, possibly because there were too few events, as 88% of the patients were still alive at last follow-up.

CONCLUSIONS

The pre-SRT PSA has a significant impact on BCR, PFS and potentially on OS, calculating either from RP or from SRT to event/censoring, respectively. This contradicts the hypothesis of lead-time bias falsifying the advantage from early SRT.

A comparison of side-effects and quality-of-life in patients operated on for prostate cancer with and without salvage radiation therapy

PURPOSE

The extent of late side-effects in prostate cancer patients, after radical prostatectomy (RP = reference group) and salvage radiation therapy (SRT) in a self-reporting perspective (PROM) is still under-reported. We aimed to investigate the rate and severity of side-effects and quality-of-life (QoL) according to PROM.

METHODS AND MATERIALS

A PROM survey was administered to a cohort of SRT patients matched to a reference group with median follow-up 10 years after surgery. In total, 740 patients were analyzed. To investigate the association between SRT versus reference group regarding side-effects and QoL, a Poisson regression analysis was conducted and presented as relative risk estimates (RR) together with 95% confidence intervals regarding questions related to urinary, rectal, sexual symptoms and QoL.

RESULTS

RRs ranged from of 1.7-6.5 on rectal symptoms and 1.2-1.4 for urinary symptoms. In general health, QoL and sexual function all RRs were below 1.1. With increasing age, higher RRs were seen for urinary leakage and lowered sexual function whereas longer time following irradiation showed higher RRs for rectal symptoms and rectal leakage. Limitations of this study include the cross-sectional design and lack of baseline assessment.

CONCLUSIONS

Adding SRT to RP does not seem to result in other than acceptable side-effects in the majority of men receiving SRT when taking a long follow-up time (median 10 years after surgery) into account. However, a subset of men develop severe side-effects where rectal bleeding dominates.

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.

Stereotactic radiotherapy for prostate bed recurrence after prostatectomy, a multicentric series

OBJECTIVE

To assess the safety and effectiveness of stereotactic salvage radiotherapy (SSRT) in RT-naïve patients affected by macroscopic prostate bed recurrence.

PATIENTS AND METHODS

Consecutive patients treated for prostate bed macroscopic recurrence in three different Italian institutes were reviewed. Patients were treated with SSRT, with a total dose of 30-40 Gy in five fractions, the mean pre-SSRT PSA level was 2.3 ng/mL. Two different PSA thresholds were defined and biochemical recurrence-free survival (BCRFS) was reported, in order to better express outcome: BCRFS1 (a PSA level increase of >10% compared to the pre-SSRT value) and BCRFS2 (a PSA level increase of >0.2 ng/mL for patients with a PSA nadir of <0.2 ng/mL or two consecutive PSA level increases of >25% compared to nadir in patients with a PSA nadir of <0.2 ng/mL).

RESULTS

In all, 90 patients were treated, with a mean (range) follow-up of 21.2 (2-64) months, and 17 of these patients (19%) had concomitant androgen-deprivation therapy (ADT) during SSRT. Complete biochemical response, defined as a PSA nadir of <0.2 ng/mL, was obtained in 39 of the 90 patients (43.3%). Considering BCRFS1, 25 patients (27.8%) had BCR, with an actuarial median BCRFS1 time of 36.4 months. For BCRFS2, BCR was reported in 32 patients (35.5%), with an actuarial median BCRFS2 time of 24.3 months. There was no Grade >2 toxicity.

CONCLUSIONS

SSRT was found to yield significant biochemical control and allowed ADT delay despite adverse features.

Adjuvant versus early salvage radiotherapy: outcome of patients with prostate cancer treated with postoperative radiotherapy after radical prostatectomy

Background

Adjuvant (ART) and salvage radiotherapy (SRT) are two common concepts to enhance biochemical relapse free survival (BCRFS) in patients with prostate cancer (PC). We analyzed differences in outcome between ART and SRT in patients with steep decline of PSA-levels after surgery to compare outcome.

Methods

We evaluated 253 patients treated with postoperative RT with a median age of 66 years (range 42–85 years) treated between 2004 and 2014. Patients with additive radiotherapy due to PSA persistence and patients in the SRT group, who did not achieve a postoperative PSA level <0.1 ng/mL were excluded. Hence, data of 179 patients was evaluated. We used propensity score matching to build homogenous groups. A Cox regression model was used to determine differences between treatment options. Median follow-up was 32.5 months (range 1.4–128.0 months).

Results

Early SRT at PSA levels <0.3 ng/mL was associated with significant longer BCRFS than late SRT (HR: 0.32, 95%-CI: 0.14–0.75, p = 0.009). Multiple Cox regression showed pre-RT PSA level, tumor stage, and Gleason score as predictive factors for biochemical relapse. In the overall group, patients treated with either ART or early SRT showed no significant difference in BCRFS (HR: 0.17, 95%-CI: 0.02–1.44, p = 0.1). In patients with locally advanced PC (pT3/4) BCRFS was similar in both groups as well (HR: 0.21, 95%-CI:0.02–1.79, p = 0.15).

Conclusion

For patients with PSA-triggered follow-up, close observation is essential and early initiation of local treatment at low PSA levels (<0.3 ng/mL) is beneficial. Our data suggest, that SRT administered at early PSA rise might be equieffective to postoperative ART in patients with locally advanced PC. However, the individual treatment decision must be based on any adverse risk factors and the patients’ postoperative clinical condition.

Study registration

The present work is approved by the Ethics Commission of the Technical University of Munich (TUM) and is registered with the project number 320/14.

Methylation Markers in Prostate Biopsies Are Prognosticators for Late Biochemical Recurrence and Therapy after Surgery in Prostate Cancer Patients

After diagnosis of prostate cancer is confirmed by a positive biopsy, the tumor may be surgically removed via radical prostatectomy (RP). However, many prostate cancer patients experience biochemical recurrence after surgery and/or undergo salvage radiotherapy or hormone therapy. Timely treatment is required to prevent the spread of disease in these cases, and biopsy tissue may hold potential for disease prognostication before surgery is ever performed. We previously developed a prognostic multigene methylation panel in RP specimens, including APC, CRIP3, HOXD3, and TGFB2. In the current study, this panel was applied to a cohort of biopsy specimens (n = 86), which were assessed for DNA methylation using the real-time quantitative PCR-based multiplex MethyLight. The biopsy-based methylation panel is significantly associated with biochemical recurrence when combined with the current clinical parameter of prostate-specific antigen (PSA) levels at diagnosis and is able to prognosticate the initiation of salvage radiotherapy, where it outperforms PSA, and/or hormone therapy after RP. In addition, this methylation panel is significantly associated with late recurrence occurring within 5 and 7 years after surgery, when combined with PSA at diagnosis. Combining DNA methylation and clinicopathologic markers at the biopsy stage will not only increase their prognostic ability but will also ensure effective patient management.

Multiparametric magnetic resonance imaging-guided salvage radiotherapy in prostate cancer

Aim

To analyse the efficacy and toxicity of postprostatectomy SRT in patients with a BCR evaluated with mpMRI.

Background

Multiparametric magnetic resonance imaging (mpMRI) has the ability to detect the site of pelvic recurrence in patients with biochemical recurrence (BCR) after radical prostatectomy (RP). However, we do not know the oncological outcomes of mpMRI-guided savage radiotherapy (SRT).

Results

Local, lymph node, and pelvic bone recurrence was observed in 13, 4 and 2 patients, respectively. PSA levels were significantly lower in patients with negative mpMRI (0.4 ng/mL [0.4]) vs. positive mpMRI (2.2 ng/mL [4.1], p = 0.003). Median planning target volume doses in patients with visible vs. non-visible recurrences were 76 Gy vs. 70 Gy. Overall, mean follow-up was 41 months (6-81). Biochemical relapse-free survival (bRFS) at 3 years was 82.3% and 82.5%, respectively, for the negative and positive mpMRI groups (p = 0.800). Three-year rates of late grade ≥2 urinary and rectal toxicity were 14.8% and 1.9%, respectively; all but one patient recovered without sequelae.

Conclusion

SRT to the macroscopic recurrence identified by mpMRI is a feasible and well-tolerated option. In this study, there were no differences in bRFS between MRI-positive and MRI-negative patients, indicating effective targeting of MRI-positive lesions.

The impact of prostate-specific antigen persistence after radical prostatectomy on the efficacy of salvage radiotherapy in patients with primary N0 prostate cancer

OBJECTIVE

To test whether salvage radiotherapy (SRT) in patients with lymph node negative (N0) prostate cancer is equally effective with persistent prostate-specific antigen (PSA) and PSA rising from the undetectable range (<0.1 ng/mL) after radical prostatectomy (RP).

PATIENTS AND METHODS

We assessed post-SRT PSA progression-free survival (PFS) in 555 patients with prostate cancer. The entire cohort was compared with a risk-adjusted subgroup of 112 patient pairs with matching pre-RP PSA level (±10 ng/mL), Gleason score (≤6 vs 7 vs ≥8), and pre-SRT PSA level (±0.5 ng/mL).

RESULTS

The median follow-up was 6.1 years. After RP, PSA was undetectable in 422 and persistent in 133 patients. PSA persistence and a pre-SRT PSA level of ≥0.5 ng/mL reduced Kaplan-Meier rates of PFS significantly. In multivariate analysis of the entire cohort and after risk adjustment, the pre-SRT PSA level but not post-RP PSA persistence was a significant parameter. In the matched cohort's subgroup with early SRT at a PSA level of <0.5 ng/mL, a trend towards a worse outcome with post-RP PSA persistence was observed. Delayed SRT with a PSA level ≥0.5 ng/mL led to a PFS of <30%, irrespective of the post-RP PSA level.

CONCLUSION

In patients with N0 prostate cancer with post-RP PSA persistence, early SRT at a PSA level <0.5 ng/mL seems to be less effective than in recurrent patients with post-RP undetectable PSA. They might benefit from intensified therapy, but larger case numbers are required to substantiate this conclusion. In patients with a PSA level ≥0.5 ng/mL and higher-risk features associated with post-RP PSA persistence, SRT alone is unlikely to provide long-term freedom from further progression.

Effect of early salvage radiotherapy at PSA < 0.5 ng/ml and impact of post-SRT PSA nadir in post-prostatectomy recurrent prostate cancer

BACKGROUND

For patients with recurrent prostate cancer after radical prostatectomy (RP), salvage radiotherapy (SRT) offers a second chance of cure. European guidelines (EAU) recommend SRT at a PSA < 0.5 ng/ml. We analyze the efficacy of SRT given according to this recommendation and investigate the predictive power of the post-SRT PSA nadir.

METHODS

Between 1998 and 2013, 301 patients of two university hospitals received SRT at a PSA < 0.5 ng/ml (median 0.192 ng/ml, IQR 0.110-0.300). Patients, who previously received androgen deprivation therapy, were excluded. All patients had 3D-conformal RT or intensity-modulated radiotherapy (IMRT, n = 59) (median 66.6 Gy). The median follow-up was 5.9 years. Progression and overall survival were the endpoints.

RESULTS

After SRT, 252 patients re-achieved an undetectable PSA. In univariate analysis, pre-RP PSA ≥ 10 ng/ml, pT3-4, Gleason score (GS) 7-10 or 8-10, negative surgical margins, post-RP PSA ≥ 0.1 ng/ml, pre-SRT PSA ≥ 0.2 ng/ml and post-SRT PSA nadir ≥ 0.1 ng/ml correlated unfavorably with post-SRT progression. In a multivariable Cox model, pT3-4, GS 7-10, negative margins and a pre-SRT PSA ≥ 0.2 ng/ml were significant risk factors. If the post-SRT PSA was added to the analysis, it dominated the outcome (HR = 9.00). Of the patients with a pre-SRT PSA < 0.2 ng/ml, only 9% failed re-achieving an undetectable PSA. Overall survival in these patients was 98% after 5.9 years compared to 91% in patients with higher pre-SRT PSA (Logrank p = 0.004).

CONCLUSIONS

SRT at a PSA < 0.2 ng/ml correlates significantly with achieving a post-SRT undetectable PSA (<0.1 ng/ml) and subsequently with improved freedom from progression. Given these overall favorable outcomes, whether additional androgen deprivation therapy is required for these men requires further study.

Outcome after PSMA PET/CT based salvage radiotherapy in patients with biochemical recurrence after radical prostatectomy: a bi-institutional retrospective analysis

Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) detects prostate cancer recurrence at low PSA levels. Radiotherapy with dose escalation to the former prostate bed has been associated with improved biochemical recurrence-free survival (BRFS). Thus, we hypothesized that PSMA PET/CT-guided salvage radiotherapy leads to improved BRFS. Methods: A total of 204 consecutive patients were referred for salvage radiotherapy following radical prostatectomy. PSMA PET/CT scans were performed and patients with PSA persistence (109 patients) or evidence of distant metastases (5 patients) were excluded from this analysis. Thus, the following analysis is based on a total of 90 patients who underwent PSMA PET/CT prior to radiotherapy due to biochemical recurrence and received salvage radiotherapy. In case of PET-positive findings, antiandrogen therapy was commenced before initiation of radiotherapy. BRFS (PSA ≤ 0.2 ng/ml) was defined as the study endpoint. Results: PET-positive lesions were detected in 42/90 (47%) patients: 24/42 (27%) fossa recurrence only, 12/42 (13%) pelvic lymph nodes only and 6/42 (7%) fossa and pelvic lymph node recurrence. Median PSA before radiotherapy was 0.44 (0.11 - 6.24). Cumulatively, a total dose of 70.0 Gy (67.2 - 72 Gy) was delivered to local macroscopic tumor, 66 Gy (59.4 - 70.2 Gy) to the prostatic fossa, 60.8 Gy (54 - 66 Gy) to PET-positive lymph nodes and 50.4 Gy (45 - 50.4 Gy) to the lymphatic pathways. After a median follow-up of 23 months, BRFS was 78%. Antiandrogen therapy was ongoing in 4 patients at last follow-up. No significant difference in BRFS between PET-positive (74%) vs. PET-negative patients (82%; p>0.05) was observed at last follow-up. Two patients had late genitourinary toxicity grade 3 and no patient had gastrointestinal toxicity ≥ 3 (NCI-CTCAE v4.03). Conclusion: PSMA PET/CT-guided salvage radiotherapy is an effective and safe local treatment option. No difference in BRFS between PET-positive and PET-negative patients was observed, indicating effective targeting of PET-positive lesions. PSMA PET/CT when readily available should be offered to patients with PSA recurrence for treatment individualization.

Outcome after PSMA PET/CT based radiotherapy in patients with biochemical persistence or recurrence after radical prostatectomy

BACKGROUND

PSMA PET/CT visualises prostate cancer residual disease or recurrence at lower PSA levels compared to conventional imaging and results in a change of treatment in a remarkable high number of patients. Radiotherapy with dose escalation to the former prostate bed has been associated with improved biochemical recurrence-free survival. Thus, it can be hypothesised that PSMA PET/CT-based radiotherapy might improve the prognosis of these patients.

METHODS

One hundred twenty-nine patients underwent PSMA PET/CT due to biochemical persistence (52%) or recurrence (48%) after radical prostatectomy without evidence of distant metastases (February 2014-May 2017) and received PSMA PET/CT-based radiotherapy. Biochemical recurrence free survival (PSA ≤ 0.2 ng/ml) was defined as the study endpoint.

RESULTS

Patients with biochemical persistence were significantly more often high-risk patients with significantly shorter time interval before PSMA PET/CT than patients with biochemical recurrence. Patients with biochemical recurrence had significantly more often no evidence of disease or local recurrence only in PSMA PET/CT, whereas patients with biochemical persistence had significantly more often lymph node involvement. Seventy-three patients were started on antiandrogen therapy prior to radiotherapy due to macroscopic disease in PSMA PET/CT. Cumulatively, 70 (66-70.6) Gy was delivered to local macroscopic tumor, 66 (63-66) Gy to the prostate fossa, 61.6 (53.2-66) Gy to PET-positive lymph nodes and 50.4 (45-52.3) Gy to lymphatic pathways. Median PSA after radiotherapy was 0.07 ng/ml with 74% of patients having a PSA ≤ 0.1 ng/ml. After a median follow-up of 20 months, median PSA was 0.07 ng/ml with ongoing antiandrogen therapy in 30 patients. PET-positive patients without antiandrogen therapy at last follow-up (45 patients) had a median PSA of 0.05 ng/ml with 89% of all patients, 94% of patients with biochemical recurrence and 82% of patients with biochemical persistence having a PSA ≤ 0.2 ng/ml. Post-radiotherapy PSA ≤ 0.1 ng/ml and biochemical recurrence vs. persistence were significantly associated with a PSA ≤ 0.2 ng/ml at last follow-up.

CONCLUSIONS

PSMA PET/CT-based radiotherapy is an effective local salvage treatment option with significant PSA response in patients with biochemical recurrence or persistence after radical prostatectomy leading to deferral of long-term ADT or systemic therapy.

Use of androgen deprivation and salvage radiation therapy for patients with prostate cancer and biochemical recurrence after prostatectomy

AIM

Overview on the use of androgen deprivation therapy (ADT) added to salvage radiation therapy (SRT) for prostate cancer patients with biochemical recurrence after prostatectomy.

METHODS

The German Society of Radiation Oncology (DEGRO) expert panel summarized available evidence published between January 2009 and May 2017, and assessed the validity of the information on outcome parameters including overall survival (OS) and treatment-related toxicity.

RESULTS

Two randomized controlled trials and nine relevant retrospective analyses were identified. The RTOG 9601 trial showed an OS improvement for the combination of 2 years of bicalutamide and SRT compared to SRT alone after a median follow-up of 13 years. This improvement appeared to be restricted to those patients with a prostate specific antigen (PSA) level before SRT of ≥0.7 ng/mL. The GETUG AFU-16 trial showed that after a median follow-up of 5 years, the addition of 6 months of goserelin to SRT improved progression-free survival (PFS; based on biochemical recurrence) as compared to SRT alone. ADT in both trials was not associated with increased major late toxicities. Results of retrospective series were inconsistent with a suggestion that the addition of ADT improved biochemical PFS especially in patients with high-risk factors such as Gleason Score ≥8 and in the group with initially negative surgical margins.

CONCLUSIONS

ADT combined with SRT appears to improve OS in patients with a PSA level before SRT of ≥0.7 ng/mL. In patients without persistent PSA after prostatectomy and PSA levels of <0.7 ng/mL, ADT should not routinely be used, but may be considered in patients with additional risk factors such as Gleason Score ≥8 and negative surgical margins.