Gaps between Evidence and Practice in Postoperative Radiotherapy for Prostate Cancer: Focus on Toxicities and the Effects on Health-Related Quality of Life

Current Status and Future Perspective on the Management of Lymph Node-Positive Prostate Cancer after Radical Prostatectomy

Pathological lymph node involvement (pN1) after a pelvic lymph node dissection represents one of the most unfavorable prognostic factors for disease recurrence and cancer-specific mortality in prostate cancer. However, optimal management for pN1 patients remains unclear. Thus, the guideline from the European Association of Urology recommends discussing three following management options with pN1 patients after an extended pelvic lymph node dissection, based on nodal involvement characteristics: (i) offer adjuvant androgen-deprivation therapy, (ii) offer adjuvant androgen-deprivation therapy with additional radiotherapy and (iii) offer observation (expectant management) to a patient with ≤2 nodes and a prostate-specific antigen <0.1 ng/mL. Treatment intensification may reduce risks of recurrence and cancer-specific mortality, but it may increase adverse events and impair quality of life. Few randomized control trials for pN1 are under investigation. In addition, there are limited reports on the quality of life and patient-reported outcomes in patients with pN1. Therefore, more research is needed to establish an optimal therapeutic strategy for patients with pN1. This review summarizes current evidence on the treatments available for men with pN1, summarizes randomized control trials that included pN1 prostate cancer, and discusses future perspectives.

Changing trends in robot-assisted radical prostatectomy: Inverse stage migration-A retrospective analysis

Background

With increasing availability of data on outcomes of surgery for prostate cancer, the profile of patients undergoing robot-assisted radical prostatectomy (RARP) has changed over the past decade. This impacts the decision-making process for surgeons and patients, particularly in low-incidence regions of Asia. Our institution was among the first in Asia to acquire a da Vinci surgical robot in 2005. We evaluated the changes in the clinical and pathology profile of patients undergoing RARP at our institution over the past 15 years (2005-2019).

Methods

A retrospective analysis of patients undergoing RARP between April 2005 and December 2019 was conducted from the hospital database. The patients were divided into two groups; patients undergoing RARP from April 2005 to December 2012 (Group I, first 8 years) and January 2013 to December 2019 (Group II, next 7 years). The perioperative characteristics were compared between these two groups to assess changes in their profile and outcome.

Results

Four hundred forty-seven patients were included in this study; 244 (54.6%) in Group I and 203 (45.4%) in Group II. The median prostate specific antigen in Group II was significantly higher than that in Group I (14.5 vs. 11.7 ng/ml, P = 0.016). Unfavorable pathological characteristics, i.e., Gleason Grade ≥3, perineural invasion, and the margin positivity rate increased substantially from 18.5% to 37.5%, 20.5% to 36.9%, and 15.2% to 26.6%, respectively, in Group II compared with Group I. More patients in Group II received adjuvant therapy than in Group I (P < 0.001).

Conclusion

There has been a change in profile of patients undergoing RARP and patients with more unfavorable disease characteristics such as higher prostate specific antigen and tumor grade are undergoing surgery. In line with international trends, the number of patients with low-grade disease undergoing surgery has substantially decreased. Multimodal treatment with adjuvant therapy is increasingly used, particularly in high-risk disease.

Salvage radiation therapy in prostate cancer: relationship between rectal dose and long-term, self-reported rectal bleeding

Purpose

To quantify the relationship between the rectal dose distribution and the prevalence of self-reported rectal bleeding among men treated with salvage radiotherapy (ST) delivered by three-dimensional conformal radiotherapy (3DCRT) for prostate cancer. To use this relationship to estimate the risk of rectal bleeding for a contemporary cohort of patients treated with volumetric modulated arc therapy (VMAT) ST.

Methods and patients

Rectal bleeding of any grade was reported by 56 (22%) of 255 men in a PROM-survey at a median follow-up of 6.7 years after 3DCRT ST. Treatment plan data were extracted and dose–response relationships for the rectal volumes receiving at least 35 Gy (V_35Gy) or 63 Gy (V_63Gy) were calculated with logistic regression. These relationships were used to estimate the risk of rectal bleeding for a cohort of 253 patients treated with VMAT ST.

Results

In the dose–response analysis of patients in the 3DCRT ST cohort, both rectal V_35Gy and V_63Gy were statistically significant parameters in univariable analysis (p = 0.005 and 0.003, respectively). For the dose–response models using either rectal V_35Gy or V_63Gy, the average calculated risk of rectal bleeding was 14% among men treated with VMAT ST compared to a reported prevalence of 22% for men treated with 3DCRT ST.

Conclusions

We identified dose–response relationships between the rectal dose distribution and the risk of self-reported rectal bleeding of any grade in a long-term perspective for men treated with 3DCRT ST. Furthermore, VMAT ST may have the potential to decrease the prevalence of late rectal bleeding.

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.

Postoperative radiotherapy for prostate cancer: the sooner the better and potential to reduce toxicity even further

PURPOSE

To evaluate biochemical relapse-free survival (bRFS), overall survival (OS), late rectal and bladder toxicities in a retrospective single institution series, also applying an in-house software for biological dose calculation.

METHODS

258 patients submitted to radiotherapy after prostatectomy were considered. Differences between groups were calculated using the log-rank test and the relevant clinical and therapeutic variables were considered for multivariate analysis. PRODVH is an in-house system able to calculate mean dose-volume histograms (DVHs) of a series of patients, to convert them in biologically effective DVHs (BEDVHs) and allowing to compare them with ANOVA and t Student test.

RESULTS

Adjuvant radiotherapy (ART) and salvage radiotherapy (SRT) were performed in 131 (50.8%) and 127 patients (49.2%). At multivariate analysis advanced T stage, androgen deprivation total (ADT) and SRT resulted as independent variables related to a worst bRFS (p = 0.019, 0.001 and 0.02), while GS > 7 and SRT affected negatively OS (p 0.047 and 0.039). High grade toxicity events occurred mainly in patients treated with 3-dimensional conformal radiotherapy (3DCRT) (proctitis p = 0.006; cystitis: p = 0.041). A significantly more favorable mean rectum BEDVH for patients with G0 or G1 rectal toxicity was shown (p < 0.001). Mean BEDVH for both bladder (p < 0.01) and rectum (p < 0.05) were also significantly better for volumetric modulated arc therapy-image guided radiotherapy (VMAT-IGRT) plans than for 3DCRT plans.

CONCLUSION

ART is better than SRT in terms of bRFS and OS, particularly for more aggressive cases, advanced T stage and higher Gleason Score. Postoperative prostate cancer radiotherapy should be applied as soon as possible after surgery. The use of modern techniques such as VMAT-IGRT significantly reduces toxicity.

Evaluation of the preimplantation worksheet in determining Calypso eligibility for men prescribed postprostatectomy radiotherapy with electromagnetic transponder guidance

This study aimed to assess the design and performance of the preimplant suitability worksheet in determining Calypso eligibility for prostate cancer patients prescribed postprostatectomy radiotherapy with electromagnetic transponder guidance. The medical records and radiotherapy planning datasets of 75 patients prospectively recruited between June 2015 and September 2016 to a Phase 2 trial evaluating electromagnetic transponder-guided postprostatectomy radiotherapy were retrospectively examined. Correlation and differences between computed tomography (CT)-defined greater trochanter and prostatic fossa landmarks were evaluated. Receiver operating characteristic curves were also generated to assess the expected and observed accuracy of the worksheet in determining Calypso eligibility. Strong correlation was demonstrated between anterior surface to planning CT-defined greater trochanter and prostate bed center distances (r = 0.95, p <0.001), with a mean difference between measurements of 1.1 cm (95% confidence interval [CI]: 0.9 to 1.3). A similar correlation coefficient was found for surface to greater trochanter location and posterior beacon location (r = 0.92, p <0.001) but with a reduced mean difference of 0.4 cm (95% CI: 0.1 to 0.6). Performance of the worksheet as assessed by planning CT data demonstrated excellent accuracy as a test to determine eligibility (area under the curve: 0.97; 95% CI: 0.92 to 1.00); however, this was not replicated using the same data captured clinically (area under the curve 0.83; 95% CI: 0.68 to 0.98). Although the greater trochanter is a good surrogate for the prostate bed center, it is better associated with the posterior beacon location. As a result, the worksheet will underestimate the truly eligible population if performed accurately and according to manufacturer guidelines. Theoretically, the worksheet could be improved if a cut off of 20 cm is used and the greater trochanter is accurately identified; however, the latter appears to be difficult to achieve in practice.

Post-Prostatectomy Image-Guided Radiotherapy: The Invisible Target Concept

In the era of intensity-modulated radiation therapy, image-guided radiotherapy (IGRT) appears crucial to control dose delivery and to promote dose escalation while allowing healthy tissue sparing. The place of IGRT following radical prostatectomy is poorly described in the literature. This review aims to highlight some key points on the different IGRT techniques applicable to prostatic bed radiotherapy. Furthermore, methods used to evaluate target motion and to reduce planning target volume margins will also be explored.