Salvage radiotherapy after robot-assisted laparoscopic radical prostatectomy

Stereotactic Radiotherapy after Radical Prostatectomy in Patients with Prostate Cancer in the Adjuvant or Salvage Setting: A Systematic Review

Simple Summary

Stereotactic body radiotherapy, a type of high-precision radiotherapy delivering high doses within few treatment sessions has proven to be effective and well tolerated in prostate cancer patients treated with definite radiotherapy. This systematic review summarizes the available data and analyzes whether this modern treatment may routinely be offered to prostate cancer patients after radical prostatectomy.

Abstract

(1) Background: Prostate cancer is the most common cancer in men and can be treated with radical prostatectomy (RPE) or radiotherapy in the primary setting. Stereotactic radiotherapy (SBRT) has proven to be effective and well tolerated in this setting. However, if SBRT is an equally promising treatment option if applied in the adjuvant or salvage setting after RPE remains unknown. (2) Methods: We searched the PubMed and Embase databases with the following full-text queries in August 2021 for any combination of the terms “SBRT”, “prostate”, “adjuvant”, “postoperative”, “salvage”, “stereotactic radiotherapy”, “prostate bed”. There were no limitations regarding publication date or language. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. (3) Results: We identified 11 individual studies that were included in this systematic review. Three publications included patients without prior radiotherapy and the remaining eight patients with prior radiotherapy. In all but two publications the radiation target was the macroscopic recurrence. SBRT was overall well tolerated with acceptable rates of acute and late gastrointestinal or genitourinary toxicity. Quality of life was published for two phase I trials with good results. There was a very heterogeneous reporting on biochemical control after SBRT. (4) Conclusions: At this point, ultra-hypofractionated RT using SBRT to the prostate bed remains experimental and its use should be restricted to clinical trials. Given the biological rationale for extreme hypofractionation in patients with prostate cancer and the acceptable toxicity rates that have been reported, further exploration of this field is warranted.

Functional and oncological outcomes of salvage external beam radiotherapy following robot-assisted radical prostatectomy in a Canadian cohort

INTRODUCTION

We sought to determine the impact of salvage radio-therapy (SRT) on oncological and functional outcomes of patients with prostate cancer after biochemical recurrence (BCR) following robot-assisted radical prostatectomy (RARP).

METHODS

Data of 70 patients with prostate cancer treated with SRT after developing BCR were retrospectively analyzed from a prospectively collected RARP database of 740 men. Oncological (prostate-specific antigen [PSA]) and functional (pads/day, International Prostate Symptom Score [IPSS], and Sexual Health Inventory for Men [SHIM]) outcomes were reported at six, 12, and 24 months after RT and adjusted for pre-SRT status.

RESULTS

Men who underwent SRT had a mean age, PSA, and time from radical prostatectomy (RP) to RT of 61.8 years (60.1-63.6), 0.5 ng/ml (0.2-0.8), and 458 days (307-747), respectively. Freedom from biochemical failure (FFBF) post-SRT, defined as a PSA nadir <0.2 ng/mL, was observed in 89%, 93%, and 81%, at six, 12, and 24 months, respectively. Undetectable PSA was observed in 14%, 35%, and 40% at the same time points, respectively. There was no significant difference in urinary continence post-SRT (p=0.56). Rate of strict continence (0 pads/day) was 71% at 24 months compared to 78% pre-SRT. Mean IPSS at six, 12, and 24 months was 3.4, 3.6, and 3.6, respectively compared to pre-RT score of 3.3 (p=0.61). The mean SHIM score pre-SRT was comparable at all time points following treatment (p=0.86).

CONCLUSIONS

In this unique Canadian experience, it appears that early SRT is highly effective for the treatment of BCR following RARP with little impact on urinary continence and potency outcomes.

Adjuvant and Salvage Radiotherapy after Radical Prostatectomy in Prostate Cancer Patients

CONTEXT

Prostate cancer (PCa) patients found to have adverse pathologic features following radical prostatectomy (RP) are less likely to be cured with surgery alone.

OBJECTIVE

To analyze the role of postoperative radiotherapy (RT) in patients with aggressive PCa.

EVIDENCE ACQUISITION

We performed a systematic literature review of the Medline and EMBASE databases. The search strategy included the terms radical prostatectomy, adjuvant radiotherapy, and salvage radiotherapy, alone or in combination. We limited our search to studies published between January 2009 and August 2016.

EVIDENCE SYNTHESIS

Three randomized trials demonstrated that immediate RT after RP reduces the risk of recurrence in patients with aggressive PCa. However, immediate postoperative RT is associated with an increased risk of acute and late side effects ranging from 15% to 35% and 2% to 8%, respectively. Retrospective studies support the oncologic efficacy of initial observation followed by salvage RT administered at the first sign of recurrence; however, the impact of this delay on long-term control remains uncertain. Hopefully, ongoing randomized trials will shed light on the role of adjuvant RT versus observation±salvage RT in individuals with adverse features at RP. Accurate patient selection based on clinical characteristics and molecular profile is crucial. Dose escalation, whole-pelvis RT, novel techniques, and the use of hormonal therapy might improve the outcomes of postoperative RT.

CONCLUSIONS

Immediate RT reduces the risk of recurrence after RP in patients with aggressive disease. However, this approach is associated with an increase in the incidence of short- and long-term side effects. Observation followed by salvage RT administered at the first sign of recurrence might be associated with durable cancer control, but prospective randomized comparison with adjuvant RT is still awaited. Dose escalation, refinements in the technique, and the concomitant use of hormonal therapies might improve outcomes of patients undergoing postoperative RT.

PATIENT SUMMARY

Postoperative radiotherapy has an impact on oncologic outcomes in patients with aggressive disease characteristics. Salvage radiotherapy administered at the first sign of recurrence might be associated with durable cancer control in selected patients but might compromise cure in others.

Localizing sites of disease in patients with rising serum prostate-specific antigen up to 1ng/ml following prostatectomy: How much information can conventional imaging provide?

PURPOSE

Accurate identification of the source of a detectable serum prostate-specific antigen (PSA) in the postprostatectomy setting is a major challenge among the urologic community. The aim of this study was to assess positivity rates of imaging examinations performed in patients with early PSA rise after prostatectomy and to summarize the management strategies adopted in this clinical scenario.

METHODS

Institutional Review Board-approved retrospective study of 142 postprostatectomy patients with PSA rise up to 1ng/ml who underwent evaluation with combination of multiparametric pelvic magnetic resonance imaging (MRI)±whole-body or bone MRI, bone scintigraphy, computed tomography (CT) chest-abdomen-pelvis, ¹⁸F-fludeoxyglucose-positron emission tomography (PET)/CT or ¹⁸F-sodium fluoride-PET/CT at a single tertiary cancer center. Imaging results were summarized per modality and compared with pathology findings.

RESULTS

Pelvic MRI was positive in 15/142 (11%) patients (14 patients with local recurrence in the surgical bed and 1 patient with pelvic osseous metastases). Of these 15, 10 patients underwent additional imaging examinations; none revealed positive findings. Of the 127 patients with negative pelvic MRI, 54 (43%) underwent additional imaging examinations; only 1/54 had positive findings (false-positive T8 lesion on bone scintigraphy and FDG-PET/CT; biopsy was negative for cancer). Overall, 12/16 patients with positive imaging findings and 75/126 (60%) patients with negative imaging received treatment (radiation, hormones or chemotherapy).

CONCLUSION

The conventional imaging identified sites of disease, almost always in the form of local recurrence, in a minority of patients with early PSA rise postprostatectomy.

Refining the American Urological Association and American Society for Radiation Oncology guideline for adjuvant radiotherapy after radical prostatectomy using the pathologic Gleason score

Recently, it has been suggested that the guideline for adjuvant radiotherapy (ART) following radical prostatectomy (RP) sponsored by the American Urological Association and American Society for Radiation Oncology (AUA/ASTRO) may result in a significant overtreatment. Thus, the objective of the present study was to refine the AUA/ASTRO guideline for ART in patients at risk for biochemical recurrence (BCR) after RP. To this end, we reviewed our prospectively maintained database and selected 193 patients who met the AUA/ASTRO ART criteria. With a median follow-up of 24.0 months, BCR rate was 17.6% (34/193). When stratified by the Gleason score, BCR rate in men with Gleason score 6 was 6.8%. There was no significant association between BCR-free survival and surgical margin (P = 0.690) and pathologic stage (P = 0.353) in patients with the Gleason score 6. However, in patients with positive surgical margins (PSMs)/pathologic stage ≥T3, there was a significant difference in BCR-free survival according to Gleason score (≤ 7 vs 8–10, P = 0.047). Multivariate Cox regression analysis demonstrated that pathologic stage ≥T3 (HR = 2.106; P = 0.018), PSMs (HR = 2.411; P = 0.003), and pathologic Gleason score 8–10 (HR = 4.715; P < 0.001) were independent predictors of BCR after RP. Therefore, in addition to pathologic stage ≥T3 and PSMs, Gleason score 8–10 predicts BCR after RP. In patients with Gleason score 6, observation rather than ART may be more appropriate regardless of stage and surgical margin status.

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.