Comparison of outcomes and toxicities among radiation therapy treatment options for prostate cancer

Local salvage therapies in patients with radio-recurrent prostate cancer following external beam radiotherapy: a systematic review and meta-analysis

INTRODUCTION

To date, radio-recurrent prostate cancer (PCa) ranks as the fourth most common urological malignancy when considering the number of men with localized PCa who undergo radiation treatment and subsequently experience a biochemical recurrence. This systematic review aimed to summarize available evidence about the outcomes of local salvage strategies in patients with local PCa recurrence following primary external-beam radiation therapy (EBRT).

METHODS

We conducted a comprehensive bibliographic search on MEDLINE, Scopus, and Web of Science Core Collection databases in October 2023 to identify studies published in the last 20 years evaluating outcomes of local salvage procedures in patients with locally radio-recurrent PCa following EBRT. The meta-analysis was performed using ProMeta 3 software when two or more studies reported the same outcome. The effect size (ES) was estimated using rates reported with its 95% confidence interval (CI).

RESULTS

Overall, 28 studies (6 prospective and 22 retrospective) including 1544 patients were included in the review. Two-year recurrence-free survival (RFS) was 84.0% (95% CI: 67.0-93.0%), 69.0% (95% CI: 42.0-87.0%), 58.0% (95% CI: 43.0-71.0%), and 45% (95% CI: 38.0-52.0%), for patients undergoing brachytherapy (BT), EBRT, Cryotherapy and High-Intensity Focused Ultrasound (HIFU), respectively. After salvage prostatectomy, RFS ranged from 75% to 78.5% at a median follow-up ranging from 18 to 35 months. Estimates for severe gastrointestinal toxicity were 2%, 3%, 3%, 4%, and 11% following cryotherapy, BT, HIFU, EBRT, and salvage radical prostatectomy, respectively.

CONCLUSIONS

In patients who underwent EBRT as primary treatment, prostate salvage re-irradiation through BT or EBRT represents the modality providing the best balance between efficacy and safety. Unfortunately, due to the low level of evidence, strong recommendations regarding the choice of any of these techniques cannot be made.

Radiation Proctitis: A Review of Pathophysiology and Treatment Strategies

Radiotherapy (RT) has become an integral part of cancer treatment worldwide; it aims to arrest the uncontrolled growth of tumor cells by using high-energy rays. Radiation proctitis is a known clinical manifestation after the RT regime for pelvic malignancies. Radiation proctitis can have a variable presentation, and there are a lot of patient-related factors that can affect the eventual outcome. In most instances, it is self-limiting; however, it can become chronic in some cases and can affect the quality of life. Many treatment options are recommended, but there has been no consensus on the treatment protocols for managing this known clinical condition. We have tried to briefly describe its pathogenesis, important factors affecting the outcome, and available treatment strategies.

Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer

Stereotactic body radiation therapy (SBRT) has become a valid option for the treatment of low- and intermediate-risk prostate cancer. In randomized trials, it was found not inferior to conventionally fractionated external beam radiation therapy (EBRT). It also compares favorably to brachytherapy (BT) even if level 1 evidence is lacking. However, BT remains a strong competitor, especially for young patients, as series with 10-15 years of median follow-up have proven its efficacy over time. SBRT will thus have to confirm its effectiveness over the long-term as well. SBRT has the advantage over BT of less acute urinary toxicity and, more hypothetically, less sexual impairment. Data are limited regarding SBRT for high-risk disease while BT, as a boost after EBRT, has demonstrated superiority against EBRT alone in randomized trials. However, patients should be informed of significant urinary toxicity. SBRT is under investigation in strategies of treatment intensification such as combination of EBRT plus SBRT boost or focal dose escalation to the tumor site within the prostate. Our goal was to examine respective levels of evidence of SBRT and BT for the treatment of localized prostate cancer in terms of oncologic outcomes, toxicity and quality of life, and to discuss strategies of treatment intensification.

Long-term expression changes of immune-related genes in prostate cancer after radiotherapy

The expression of immune-related genes in cancer cells can alter the anti-tumor immune response and thereby impact patient outcomes. Radiotherapy has been shown to modulate immune-related genes dependent on the fractionation regimen. To identify long-term changes in gene expression after irradiation, PC3 (p53 deleted) and LNCaP (p53 wildtype) prostate cancer cells were irradiated with either a single dose (SD, 10 Gy) or a fractionated regimen (MF) of 10 fractions (1 Gy per fraction). Whole human genome arrays were used to determine gene expression at 24 h and 2 months after irradiation. Immune pathway activation was analyzed with Ingenuity Pathway Analysis software. Additionally, 3D colony formation assays and T-cell cytotoxicity assays were performed. LNCaP had a higher basal expression of immunogenic genes and was more efficiently killed by cytotoxic T-cells compared to PC3. In both cell lines, MF irradiation resulted in an increase in multiple immune-related genes immediately after irradiation, while at 2 months, SD irradiation had a more pronounced effect on radiation-induced gene expression. Both immunogenic and immunosuppressive genes were upregulated in the long term in PC3 cells by a 10 Gy SD irradiation but not in LNCaP. T-cell-mediated cytotoxicity was significantly increased in 10 Gy SD PC3 cells compared to the unirradiated control and could be further enhanced by treatment with immune checkpoint inhibitors. Irradiation impacts the expression of immune-related genes in cancer cells in a fractionation-dependent manner. Understanding and targeting these changes may be a promising strategy for primary prostate cancer and recurrent tumors.

Patient-Reported Quality of Life Outcomes after Moderately Hypofractionated and Normofractionated Proton Therapy for Localized Prostate Cancer

We retrospectively evaluated the three-year patient-reported quality of life (QOL) after moderately hypofractionated proton therapy (MHPT) for localized prostate cancer in comparison with that after normofractionated PT (NFPT) using the Expanded Prostate Cancer Index Composite-50. Patients who received MHPT (60-63 Gy (relative biological effectiveness equivalents; RBE)/20-21 fractions) (n = 343) or NFPT (74-78 Gy (RBE)/37-39 fractions) (n = 296) between 2013 and 2016 were analyzed. The minimum clinically important difference (MCID) threshold was defined as one-half of a standard deviation of the baseline value. The median follow-up was 56 months and 83% completed questionnaires at 36 months. Clinically meaningful score deterioration was observed in the urinary domain at 1 month in both groups and in the sexual domain at 6-36 months in the NFPT group, but not observed in the bowel domain. At 36 months, the mean score change for urinary summary was -0.3 (MHPT) and -1.6 points (NFPT), and that for bowel summary was +0.1 and -2.0 points; the proportion of patients with MCID was 21% and 24% for urinary summary and 18% and 29% for bowel summary. Overall, MHPT had small negative impacts on QOL over three years, and the QOL after MHPT and NFPT was similar.

Salvage therapy for prostate cancer after radical prostatectomy

More than 40% of men with intermediate-risk or high-risk prostate cancer will experience a biochemical recurrence after radical prostatectomy. Clinical guidelines for the management of these patients largely focus on the use of salvage radiotherapy with or without systemic therapy. However, not all patients with biochemical recurrence will go on to develop metastases or die from their disease. The optimal pre-salvage therapy investigational workup for patients who experience biochemical recurrence should, therefore, include novel techniques such as PET imaging and genomic analysis of radical prostatectomy specimen tissue, as well as consideration of more traditional clinical variables such as PSA value, PSA kinetics, Gleason score and pathological stage of disease. In patients without metastatic disease, the only known curative intervention is salvage radiotherapy but, given the therapeutic burden of this treatment, importance must be placed on accurate timing of treatment, radiation dose, fractionation and field size. Systemic therapy also has a role in the salvage setting, both concurrently with radiotherapy and as salvage monotherapy.

[On the practice of therapy decision in locally limited prostate cancer: surgery vs. radiation-who benefits? : Allocation and results of a monocentric, cumulative long-term study]

AIM

The goal of this two-armed observational study was to map the clinical therapy effectiveness of radical prostatovesiculectomy (RPVE) and external beam radiation therapy (EBRT) in locally limited prostate cancer (PCA) in direct comparison over 20 years under clinical conditions. Retrospectively, the various variables and predictors for the individual therapy decision were identified, and the preference was to compared with studies on survival and recurrence characteristics. The presentation of toxicity was not the focus of this work.

METHODOLOGY

In all, 743 patients from a single center were enrolled according to biopsy/staging chronologically in the sequence of the initial consultation after clarification and informed consent: 494 patients were in the RPVE arm and 249 patients in the EBRT arm. We used retrospective data analysis with univariate and multivariate comparisons in the alternative therapy arms. Multivariate logical regression models were developed to objectify the allocation process. Univariate processing of survival analyses, the comparison of tumor- and comorbidity-specific mortality rates was co-founded.

RESULTS

Predictive variables for RPVE vs. EBRT therapy decision are significantly age, Gleason score, D'Amico index, Charlson index, prostate-specific antigen (PSA), and prostate volume. There was no significance level for the biopsy score. The age gap was in the median 67 (RPVE) and 73 (EBRT) years. Overall survival (n = 734, 20 years, all risks) in the RPVE arm was 56.8% (95% confidence interval [CI] 45.1-67.0%) and in the EBRT arm 19.2% (95%CI 9.2-31.8%). Comorbid risk was highly significantly (p < 0.0001) different (27.1% [95%CI 18.0-36.1%] in the RPVE arm, and 60.4% [95%CI 47.3-73.5%] in the EBRT arm). The risk of tumor-specific death at 16.2% (95%CI 8.1-24.4%) after RPVE and 20.5% (95%CI 11.7-29.3%) after EBRT was not significantly different (p = 0.2122, overlapping 95%CI). After stratification, a clear advantage can be demonstrated for the high-risk tumors after allocation to the RPVE arm.

CONCLUSIONS

The complexity of the predictive variables of the PCA further complicates the individual therapy decision. According to our data, the higher D'Amico score, the rather low Charlson index, a high Gleason score and a higher organ volume speak for a valid therapy for RPVE.

Cost-Utility Analysis of Radiation Treatment Modalities for Intermediate-Risk Prostate Cancer

INTRODUCTION

Variable costs of different radiation treatment modalities have played an important factor in selecting the most appropriate treatment for patients with intermediate-risk prostate cancer.

METHODS

Analysis using a Markov model was conducted to simulate 20-year disease trajectory, quality-adjusted life years (QALYs) and health system costs of a cohort of intermediate-risk prostate cancer patients with mean age of 60 years. Clinical outcomes on toxicity and disease recurrence were measured and a probabilistic sensitivity analysis was performed, varying input parameters simultaneously according to their distributions.

RESULTS

Among the six radiation treatment modalities, including conventionally fractionated intensity-modulated radiation therapy (IMRT), hypofractionated IMRT, IMRT combined with high-dose-rate (HDR) brachytherapy, HDR brachytherapy monotherapy, low-dose-rate brachytherapy monotherapy, and stereotactic body radiotherapy (SBRT), SBRT was found to be more cost-effective when compared with LDR-b and other treatment modalities, resulting in an incremental cost-utility ratio of $2985 per QALY.

CONCLUSIONS

Stereotactic body radiotherapy is the most cost-effective radiation treatment modality in treatment of intermediate-risk prostate cancer, while treatment toxicity and cost data are the key drivers of the cost-utility. Further work is required with long-term follow-up for SBRT.

Phase 3 multicenter randomized trial of PSMA PET/CT prior to definitive radiation therapy for unfavorable intermediate-risk or high-risk prostate cancer [PSMA dRT]: study protocol

BACKGROUND

Definitive radiation therapy (dRT) is an effective initial treatment of intermediate-risk (IR) and high-risk (HR) prostate cancer (PCa). PSMA PET/CT is superior to standard of care imaging (CT, MRI, bone scan) for detecting regional and distant metastatic PCa. PSMA PET/CT thus has the potential to guide patient selection and the planning for dRT and improve patient outcomes.

METHODS

This is a multicenter randomized phase 3 trial (NCT04457245). We will randomize 312 patients to proceed with standard dRT (control Arm, n = 150), or undergo a PSMA PET/CT scan at the study site (both 18F-DCFPyL and 68Ga-PSMA-11 can be used) prior to dRT planning (intervention arm, n = 162). dRT will be performed at the treating radiation oncologist facility. In the control arm, dRT will be performed as routinely planned. In the intervention arm, the treating radiation oncologist can incorporate PSMA PET/CT findings into the RT planning. Androgen deprivation therapy (ADT) is administered per discretion of the treating radiation oncologist and may be modified as a result of the PSMA PET/CT results. We assume that approximately 8% of subjects randomized to the PSMA PET arm will be found to have M1 disease and thus will be more appropriate candidates for long-term systemic or multimodal therapy, rather than curative intent dRT. PET M1 patients will thus not be included in the primary endpoint analysis. The primary endpoint is the success rate of patients with unfavorable IR and HR PCa after standard dRT versus PSMA PET-based dRT. Secondary Endpoints (whole cohort) include progression free survival (PFS), metastasis-free survival after initiation of RT, overall survival (OS), % of change in initial treatment intent and Safety.

DISCUSSION

This is the first randomized phase 3 prospective trial designed to determine whether PSMA PET/CT molecular imaging can improve outcomes in patients with PCa who receive dRT. In this trial the incorporation of PSMA PET/CT may improve the success rate of curative intent radiotherapy in two ways: to optimize patient selection as a biomarker and to personalizes the radiotherapy plan.

CLINICAL TRIAL REGISTRATION

UCLA IND#147591 ○ Submission: 02.27.2020 ○ Safe-to-proceed letter issued by FDA: 04.01.2020 UCLA IRB #20-000378 ClinicalTrials.gov Identifier NCT04457245 . Date of Registry: 07.07.2020. Essen EudraCT 2020-003526-23.

Improving the therapeutic ratio of radiotherapy against radioresistant cancers: Leveraging on novel artificial intelligence-based approaches for drug combination discovery

Despite numerous advances in cancer radiotherapy, tumor radioresistance remain one of the major challenges limiting treatment efficacy of radiotherapy. Conventional strategies to overcome radioresistance involve understanding the underpinning molecular mechanisms, and subsequently using combinatorial treatment strategies involving radiation and targeted drug combinations against these radioresistant tumors. These strategies exploit and target the molecular fingerprint and vulnerability of the radioresistant clones to achieve improved efficacy in tumor eradication. However, conventional drug-screening approaches for the discovery of new drug combinations have been proven to be inefficient, limited and laborious. With the increasing availability of computational resources in recent years, novel approaches such as Quadratic Phenotypic Optimization Platform (QPOP), CURATE.AI and Drug Combination and Prediction and Testing (DCPT) platform have emerged to aid in drug combination discovery and the longitudinally optimized modulation of combination therapy dosing. These platforms could overcome the limitations of conventional screening approaches, thereby facilitating the discovery of more optimal drug combinations to improve the therapeutic ratio of combinatorial treatment. The use of better and more accurate models and methods with rapid turnover can thus facilitate a rapid translation in the clinic, hence, resulting in a better patient outcome. Here, we reviewed the clinical observations, molecular mechanisms and proposed treatment strategies for tumor radioresistance and discussed how novel approaches may be applied to enhance drug combination discovery, with the aim to further improve the therapeutic ratio and treatment efficacy of radiotherapy against radioresistant cancers.

Urinary Outcomes for Men With High Baseline International Prostate Symptom Scores Treated With Prostate SBRT

Purpose

There are limited data regarding high-dose stereotactic body radiation therapy (SBRT) for prostate cancer in patients with poor baseline urinary function. The purpose of this study was to evaluate genitourinary (GU) toxicity and changes in patient-reported symptom severity scores after prostate SBRT in men with a high pretreatment International Prostate Symptom Score (IPSS).

Methods and Materials

Seven hundred fifty-three patients treated with prostate SBRT at our institution from 2012 to 2019 were identified, of whom 72 consecutive patients with baseline IPSS ≥15 were selected for this study. GU toxicity according to Common Terminology Criteria for Adverse Events (CTCAE) v3.0 and IPSS were prospectively documented at each follow-up visit. Univariable logistic regression was used to evaluate for potential predictors of GU toxicity.

Results

Median follow-up in survivors was 26.8 months. The rates of acute grade 2 and 3 GU toxicity were 20.8% and 1.4%, respectively. The rates of late grade 2 and 3 GU toxicity were 37.5% and 5.6%, respectively. The majority of grade 2+ toxicities resolved by last follow-up, and when toxicities were regraded per CTCAE v5.0, there were no longer any grade 3 adverse events. Total IPSS and individual symptom subscores improved over time. Compared with baseline, median total IPSS at 24 ± 6 months was significantly lower (18 vs 12; P < .001) and the proportion of patients with severe scores (IPSS ≥20) decreased from 29.2% to 13.9%. Pretreatment urinary urgency was associated with late grade 2+ GU toxicity (odds ratio, 2.10; 95% confidence interval, 1.33-3.31; P = .001).

Conclusions

In men with baseline IPSS ≥15 managed with prostate SBRT, the rate of severe GU toxicity was low and patient-reported symptoms generally improved over time. Thus, high pretreatment IPSS should not deter clinicians from offering prostate SBRT.

External beam radiotherapy for prostate cancer: What are the current research trends and hotspots?

Background

The external beam radiotherapy (EBRT) applied for prostate cancer (PCa) has been one of the most important and hottest research fields over recent decades. This study aimed to explore the research hotspots of EBRT in PCa and help the researchers have a clear and intuitive reference basis for later researches.

Methods

The literature scientometric analysis related to “EBRT applied for PCa” was conducted via the Web of Science Core Collection from 2010 to 2019. The Microsoft Office Excel 2019 and CiteSpace V. 5.7.R1 software were introduced for visualizing and analyzing the data.

Results

A total of 7860 relevant papers were extracted and downloaded. A total of 7828 papers were extracted and analyzed after data cleansing by CiteSpace. The tendency of published papers was comprehensively increasing from 2010 to 2019. Among all 73 countries/regions, USA published the most papers, accounting for 39%, which was the most active contributor with most publications. Australia (Centrality: 0.18), England (Centrality: 0.12) were cooperating most cohesively with other countries. Univ Toronto was the most productive institute (229), while Harvard Univ (Centrality: 0.67) had extensive collaborations with other institutes. The International journal of Radiation Oncology Biology Physics had the largest number of publications and the highest number of co‐citations. Briganti A had the largest volume of publications. D'Amico AV had the highest number of co‐citations. Four latest and largest clusters were identified as oligometastases, salvage therapy (SRT), prostate‐specific membrane antigen (PSMA), and hypofractionation. Thirteen references became strongest burst citations lasting until 2019. The studies of “oligometastases,” “SRT,” “PSMA,” “hypofractionation,” “postoperative radiotherapy,” and “dose and fraction regimen changes” were prevailing in the recent years.

Conclusion

The “oligometastases,” “SRT,” “PSMA,” “hypofractionation,” “postoperative radiotherapy,” and “dose and fraction regimen changes” may be the state‐of‐art research frontiers, and related studies will advance in this field over time.

Neuropeptide Y nerve paracrine regulation of prostate cancer oncogenesis and therapy resistance

BACKGROUND

Nerves are key factors in prostate cancer (PCa) progression. Here, we propose that neuropeptide Y (NPY) nerves are key regulators of cancer-nerve interaction.

METHODS

We used in vitro models for NPY inhibition studies and subsequent metabolomics, apoptotic and migration assays, and nuclear transcription factor-κB (NF-κB) translocation studies. Human naïve and radiated PCa tissues were used for NPY nerve density biomarker studies. Tissues derived from a Botox denervation clinical trial were used to corroborate metabolomic changes in humans.

RESULTS

Cancer cells increase NPY positive nerves in vitro and in preneoplastic human tissues. NPY-specific inhibition resulted in increased cancer apoptosis, decreased motility, and energetic metabolic pathway changes. A comparison of metabolomic response in NPY-inhibited cells with the transcriptome response in human PCa patients treated with Botox showed shared 13 pathways, including the tricarboxylic acid cycle. We identified that NF-κB is a potential NPY downstream mediator. Using in vitro models and tissues derived from a previous human chemical denervation study, we show that Botox specifically, but not exclusively, inhibits NPY in cancer. Quantification of NPY nerves is independently predictive of PCa-specific death. Finally, NPY nerves might be involved in radiation therapy (RT) resistance, as radiation-induced apoptosis is reduced when PCa cells are cocultured with dorsal root ganglia/nerves and NPY positive nerves are increased in prostates of patients that failed RT.

CONCLUSION

These data suggest that targeting the NPY neural microenvironment may represent a therapeutic approach for the treatment of PCa and resistance through the regulation of multiple oncogenic mechanisms.

Treatment interruptions affect biochemical failure rates in prostate cancer patients treated with proton beam therapy: Report from the multi-institutional proton collaborative group registry

INTRODUCTION

To date, no studies examining the effect of treatment interruptions (TI) with proton beam therapy (PBT) have been published. The goal of our study was to determine the predictors of TI amongst patients with prostate cancer (PCa) treated with PBT and to determine whether TI are associated with biochemical failure (BF). We hypothesized that any correlation between TI and biochemical control would be more pronounced in high risk groups.

METHODS

Data for 4278 patients with PCa was obtained from the prospectively collected Proton Collaborative Group (PCG) data registry. Univariate and multivariate logistic regression analysis (MVA) was used to model possible predictors of BF. A subset analysis was performed for high risk patients treated with ADT and PBT. Finally, propensity score (PS) analysis was performed to account for any indication bias caused by lack of randomization.

RESULTS

Total treatment duration (OR, 1.05 [1.04-1.06]; p < 0.001) increased the likelihood of TI on MVA. TI did not have a statistically significant correlation with BF (OR, 1.44 [0.86-2.39]; p = 0.162) amongst PS matched patients. However, on subset analyses of high risk group patients with PS matching, there was a trend towards worse BF in patients with TI (OR 3.85; 95%CI (0.96-15.44); p = 0.057).

CONCLUSION

In the first analysis of its kind, the results suggest that TI in high risk PCa patients treated with PBT and ADT have worse BF rates. Interventions such as increased patient education, proper maintenance of proton facilities, and decreasing total treatment duration with alternative fractionation schedules may help avoid the unintended negative effects on tumor control due to TI. However, future analyses on a larger patient population is needed.

False positive PSMA PET for tumor remnants in the irradiated prostate and other interpretation pitfalls in a prospective multi-center trial

Purpose

Readers need to be informed about potential pitfalls of [⁶⁸Ga]Ga-PSMA-11 PET interpretation.

Methods

Here we report [⁶⁸Ga]Ga-PSMA-11 PET findings discordant with the histopathology/composite reference standard in a recently published prospective trial on 635 patients with biochemically recurrent prostate cancer.

Results

Consensus reads were false positive in 20 regions of 17/217 (8%) patients with lesion validation. Majority of the false positive interpretations (13 of 20, 65%) occurred in the context of suspected prostate (bed) relapse (T) after radiotherapy (n = 11); other false positive findings were noted for prostate bed post prostatectomy (T, n = 2), pelvic nodes (N, n = 2), or extra pelvic lesions (M, n = 5). Major sources of false positive findings were PSMA-expressing residual adenocarcinoma with marked post-radiotherapy treatment effect. False negative interpretation occurred in 8 regions of 6/79 (8%) patients with histopathology validation, including prostate (bed) (n = 5), pelvic nodes (n = 1), and extra pelvic lesions (n = 2). Lesions were missed mostly due to small metastases or adjacent bladder/urine uptake.

Conclusion

[⁶⁸Ga]Ga-PSMA-11 PET at biochemical recurrence resulted in less than 10% false positive interpretations. Post-radiotherapy prostate uptake was a major source of [⁶⁸Ga]Ga-PSMA-11 PET false positivity. In few cases, PET correctly detects residual PSMA expression post-radiotherapy, originating however from treated, benign tissue or potentially indolent tumor remnants.

Trial registration number

ClinicalTrials.gov Identifiers: NCT02940262 and NCT03353740.

Electronic supplementary material

The online version of this article (10.1007/s00259-020-04945-1) contains supplementary material, which is available to authorized users.

Radical radiotherapy for prostate cancer: patterns of care in Sweden 1998-2016

Introduction: Radiotherapy is an established treatment option for prostate cancer (PCa), both as primary treatment and secondary treatment after radical prostatectomy (RP). Since 1998, detailed data on radiotherapy delivered to Swedish men with PCa (e.g. treatment modalities, absorbed doses, fractionation) have been collated within PCa data Base Sweden (PCBaSe). This study reports patterns of radical radiotherapy for PCa in Sweden over the past two decades.Materials and methods: All men with non-metastatic PCa (1998-2016) who received external beam radiotherapy (EBRT) or high or low dose-rate brachytherapy (HDR-BT/LDR-BT) were identified in PCBaSe. Analyses included: trends in radiation techniques, fractionation patterns and total doses over time; PCa-specific survival comparing treatment in 2007-2017 with 1998-2006; and regional variation in type of primary radiotherapy.Results: About 20,876 men underwent primary radiotherapy. The main treatment modalities include conventionally fractionated (2.0 Gy/fraction) EBRT (51%), EBRT with HDR-BT boost (27%) and hypofractionated (>2.4 Gy/fraction) EBRT (11%). EBRT with photon or proton boost and HDR-BT and LDR-BT monotherapies were each used minimally. Use of dose-escalated EBRT (>74 Gy) and moderate hypofractionation increased over time, while use of HDR-BT declined. Considerable regional variation in treatment modalities was apparent. Risk of PCa death following primary radiotherapy had declined for intermediate-risk (HR: 0.60; 95%CI 0.47-0.87) and high-risk PCa (HR: 0.72; 95%CI 0.61-0.86).Discussion: Increased use of dose escalation and hypofractionated EBRT has occurred in Sweden over the past two decades, reflecting current evidence and practice guidelines. Disease-specific outcomes have also improved. Data collected in PCBaSe provide an excellent resource for further research into RT use in PCa management.

Contemporary treatments in prostate cancer focal therapy

PURPOSE OF REVIEW

Radical treatments for prostate cancer are associated with significant morbidity, including incontinence and erectile dysfunction. Advances in the field of prostate MRI and desire to reduce treatment morbidities have led to a rapid growth in focal treatments for prostate cancer. Here, we review novel focal prostate cancer treatments and their associated recent clinical data, with a particular focus on data reported within the last 24 months.

RECENT FINDINGS

High-intensity focal ultrasound, focal laser ablation, irreversible electroporation, focal cryotherapy, and photodynamic therapy have been used as treatment modalities for localized prostate cancer treatment. Despite the great variety of treatment techniques, each of these modalities is characterized by a significant rate of prostate cancer persistence within treatment zones (6-50%) and the presence of residual cancer within the prostate on rebiopsy (24-49%). These treatments, however, are associated with very low rates of high-grade complications, rare incontinence, and only mild or transient reductions in erectile function. The most common adverse events are urinary tract infections, hematuria, and urinary retention.

SUMMARY

Prostate cancer focal therapy is an attractive option for well-selected patients because of its low complication profile; however, long-term oncologic outcome is still lacking and early recurrence rates are high, limiting the ability of most urologic associations from endorsing its routine use.

The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

PURPOSE

To determine the best method to contour the planning organ at risk volume (PRV) for the urethra, this study aimed to investigate the displacement of a Foley catheter in the urethra with a soft and thin guide-wire.

METHODS

For each patient, the study used two sets of computed tomography (CT) images for radiation treatment planning (RT-CT): (1) set with a Foley urethral catheter (4.0 mm diameter) plus a guide-wire (0.46 mm diameter) in the first RT-CT and (2) set with a guide-wire alone in the second CT recorded 2 min after the first RT-CT. Using three fiducial markers in the prostate for image fusion, the displacement between the catheter and the guide-wire in the prostatic urethra was calculated. In 155 consecutive patients treated between 2011 and 2017, 5531 slices of RT-CT were evaluated.

RESULTS

Assuming that ≥3.0 mm of difference between the catheter and the guide-wire position was a significant displacement, the urethra with the catheter was displaced significantly from the urethra with the guide-wire alone in > 20% of the RT-CT slices in 23.2% (36/155) of the patients. The number of patients who showed ≥3.0 mm anterior displacement with the catheter in ≥20% RT-CT slices was significantly larger at the superior segment (38/155) than at the middle (14/155) and inferior segments (18/155) of the prostatic urethra (p < 0.0167).

CONCLUSIONS

The urethral position with a Foley catheter is different from the urethral position with a thin and soft guide-wire in a significant proportion of the patients. This should be taken into account for the PRV of the urethra to ensure precise radiotherapy such as in urethra-sparing radiotherapy.

Single fraction high-dose-rate brachytherapy as monotherapy for low and intermediate risk prostate cancer: toxicities and early outcomes from a single institutional experience

Purpose

High-dose-rate brachytherapy (HDR-BT) delivered in a single fraction as monotherapy is a potential treatment modality for low- and intermediate-risk prostate cancer (LIR-PC); however, outcome data with this technique remain limited. Here we describe our institutional HDR monotherapy experience and report the efficacy and toxicity of this treatment.

Material and methods

LIR-PC patients who received a definitive single fraction HDR-BT during 2013-2017 were retrospectively identified. The intended HDR monotherapy dose was 19 Gy in one fraction. Acute (< 90 days) and late (≥ 90 days) toxicity was assessed using CTCAE version 4.03. Trends in prostate-specific antigen (PSA) and American Urological Association (AUA) symptom scores after treatment were assessed using Bayesian linear mixed models. The Kaplan-Meier method was used to evaluate biochemical failure-free survival (BFFS).

Results

28 patients with median follow-up of 23.6 months were identified. The median age at treatment was 65 years (48-83). The NCCN risk groups were low in 14, favorable intermediate in 10, and unfavorable intermediate in 4 patients. There were 5 (18%) and 0 (0%) acute grade 2 genitourinary (GU) and gastrointestinal (GI) toxicities, respectively, and one (4%) acute grade 3 GU toxicity. There were no late grade 3 toxicities, and 5 (18%) and 0 (0%) late grade 2 GU and GI toxicities respectively. PSA values and AUA symptom scores decreased significantly after treatment. There were 3 biochemical failures with the two- and three-year BFFS of 90.7% and 80.6%, respectively.

Conclusions

Early results from a single institution suggest that single fraction HDR-BT with 19 Gy has limited toxicity, although with suboptimal biochemical control.

Targeted biopsy: benefits and limitations

PURPOSE OF REVIEW

To review the current literature regarding the role of multiparametric MRI and fusion-guided biopsies in urologic practice.

RECENT FINDINGS

Fusion biopsies consistently show an increase in the detection of clinically significant cancers and decrease in low-risk disease that may be more suitable for active surveillance. Although, when to incorporate multiparametric MRI into workup is not clearly agreed upon, studies have shown a clear benefit in both biopsy naïve and those with prior negative biopsies in determining the appropriate treatment strategy. More recently, cost-analysis models have been published that show that upfront MRIs are more cost-effective when considering missed cancers and treatment courses.

SUMMARY

With improved accuracy over systematic biopsies, fusion biopsies are a superior method for detection of the true grade of cancer for both biopsy naïve and patients with prior negative biopsies, choosing appropriate candidates for active surveillance, and monitoring progression on active surveillance.

Treatment patterns of high-dose-rate and low-dose-rate brachytherapy as monotherapy for prostate cancer

PURPOSE

Monotherapy with high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy are both recommended modalities for prostate cancer. The choice between HDR and LDR is dependent on patient, physician, and hospital preferences. We sought to identify treatment patterns and factors associated with receipt of HDR or LDR monotherapy.

MATERIAL AND METHODS

We queried the National Cancer Database (NCDB) for patients with localized low- or intermediate-risk prostate cancer treated with HDR or LDR monotherapy. Descriptive statistics were used to analyze patterns of HDR vs. LDR. Patient characteristics were correlated with HDR vs. LDR using multivariable logistic regression.

RESULTS

We identified 50,326 patients from 2004-2014: LDR 37,863 (75.2%) vs. HDR 12,463 (24.8%). Median follow-up was 70.3 months. The overall use of monotherapy declined over time. HDR application declined relative to LDR. In 2004, 27.0% of cases were HDR compared to 19.2% in 2014. Factors associated with increased likelihood of HDR on multivariable analysis included: increasing age (OR: 1.01, 95% CI: 1.01-1.01), cT2c disease (OR: 1.25, 95% CI: 1.11-1.41), treatment at an academic center (OR: 2.45, 95% CI: 2.24-2.65), non-white race (OR: 1.34, 95% CI: 1.27-1.42), and income > $63,000 (OR: 1.73, 95% CI: 1.59-1.88). LDR was more common in 2010-2014 (OR: 0.59, 95% CI: 0.54-0.65), Charlson-Deyo comorbidity index > 0 (OR: 0.89, 95% CI: 0.84-0.95), and for patients receiving hormone therapy (OR: 0.88, 95% CI: 0.83-0.93). No difference in prostate-specific antigen (PSA) or Gleason score and receipt of HDR vs. LDR was observed. Mean overall survival was 127.0 months for HDR and 125.4 for LDR, and was not statistically different.

CONCLUSIONS

We observed an overall decrease in brachytherapy (BT) monotherapy use since 2004 for localized prostate cancer. Despite similar survival outcomes, the use of HDR monotherapy declined relative to LDR.

Consensus statements on the management of clinically localized prostate cancer from the Hong Kong Urological Association and the Hong Kong Society of Uro-Oncology

OBJECTIVE

To formulate consensus statements to facilitate physician management strategies for patients with clinically localized prostate cancer (PCa) in Hong Kong by jointly convening a panel of 12 experts from the two local professional organizations representing PCa specialists, who had previously established consensus statements on the management of metastatic PCa for the locality.

METHODS

Through a series of meetings, the panellists discussed their clinical experience and the published evidence regarding various areas of the management of localized PCa, then drafted consensus statements. At the final meeting, each drafted statement was voted on by every panellist based on its practicability of recommendation in the locality.

RESULTS

A total of 76 consensus statements were ultimately accepted and established by panel voting.

CONCLUSION

Derived from the recent evidence and major overseas guidelines, along with local clinical experience and practicability, the consensus statements were aimed to serve as a practical reference for physicians in Hong Kong for the management of localized PCa.

Medical Student Decision-Making: Standard Surgical Excision or Mohs Micrographic Surgery to Manage Basal Cell Carcinoma

Context

As future physicians, osteopathic medical students will play a critical role in helping patients make informed decisions regarding treatment options.

Objective

To examine the influence that the time, cost, and cosmetic effects associated with treatment options for basal cell carcinoma (BCC), along with students' demographic characteristics, have on treatment decision-making. The influence that different sources of information have on students was also studied.

Methods

Medical students were recruited from the Nova Southeastern University College of Osteopathic Medicine for this cross-sectional study. Students were presented with a case scenario in which they were a patient with primary nodular BCC in a low-risk zone, and they were asked to select standard surgical excision (SSE) or Mohs micrographic surgery (MMS) as a treatment option. They also completed an anonymous survey that assessed the way that factors associated with the treatment options (time, cost, and cosmetic effects) influenced their treatment choice, along with the influence that different sources of information have. Measures of central tendency, frequencies, and other descriptive analyses were used to define the characteristics of the sample. χ2 analysis, correlational analysis, and t tests were used to examine the associations between the treatment decision, treatment-related factors (time, cost, cosmetics), and year in medical school. Statistical significance was set at P≤.05.

Results

A total of 450 students completed the survey and were included in the bivariate analysis. Three hundred forty-five students (76.7%) selected MMS as a treatment option and 105 (23.3%) selected SSE. Significant differences were found in the influence of time, cost, and cosmetic effects associated with treatment between students who selected MMS and those who selected SSE (P<.001). Cost played a more influential role in treatment decision-making for students who selected SSE than for those who selected MMS. Time and cosmetic effects played a more influential role in treatment choice for those who selected MMS. The most influential sources of information were health care professionals and medical literature, with 398 (88.4%) and 313 (69.6%) students, respectively, indicating that these sources were highly influential when making medical treatment decisions. The internet had a low influence over students' treatment decision-making (238 [52.9%]).

Conclusions

This study represents an initial step toward understanding factors that influence patients' treatment decision-making in a situation in which there is no medically preferred treatment option. The findings point to the importance of time, cost, and cosmetics as influential factors for patients choosing between different treatment options.

Comparison of volumetric-modulated arc therapy and intensity-modulated radiation therapy prostate cancer plans accounting for cold spots

This study compared dosimetric indices of volumetric-modulated arc therapy (VMAT) with intensity-modulated radiation therapy (IMRT) accounting for cold spots in prostate cancer plans. IMRT plans were retrospectively generated from 30 prostate cancer patients with ten cases for each risk group, who received VMAT plans. The mean, maximum, and minimum doses, and conformity and homogeneity indexes were evaluated for planning target volume (PTV) and the mean dose and V20-V70 for organs at risk (OAR) including the rectum, bladder, right and left femoral heads, and rectum overlapped with PTV (ROP) regions. The numbers and volume percentages of cold spots within PTVs and ROP regions were measured using in-house software. Three-dimensional probabilistic distributions of the probability and distributions of cold spots were generated using a centroid matching technique for visualization and analysis. There was a statistically better dose conformity in the PTV, rectum, and bladder dose-sparing in VMAT compared to that in the IMRT plans, whereas VMAT had statistically worse target dose homogeneity, and right and left femoral head dose-sparing than those of the IMRT plans. The average volume percentage of cold spots per PTV for the VMAT was 4.37 ± 2.68%, which was smaller than the 5.72 ± 1.84% observed for IMRT plans (P = 0.007). The volume percentage of cold spots per ROP for the VMAT did not significantly differ from those for the IMRT plans. Compared with IMRT, the VMAT plans achieved better PTV dose conformity, OAR dose-sparing, and smaller cold spots in the treatment of prostate cancer.

UK & Ireland Prostate Brachytherapy Practice Survey 2014-2016

Purpose

To document the current prostate brachytherapy practice across the UK and Ireland and compare with previously published audit results.

Material and methods

Participants from 25 centers attending the annual UK & Ireland Prostate Brachytherapy Conference were invited to complete an online survey. Sixty-three questions assessed the center’s experience and staffing, clinician’s experience, clinical selection criteria and scheduling, number of cases per modality in the preceding three years, low-dose-rate (LDR) pre- and post-implant technique and high-dose-rate (HDR) implant technique. Responses were collated, and descriptive statistical analysis performed.

Results

Eighteen (72%) centers responded with 17 performing LDR only, 1 performing HDR only, and 6 performing both LDR and HDR. Seventy-one percent of centers have > 10 years of LDR brachytherapy experience, whereas 71% centers that perform HDR brachytherapy have > 5 years of experience. Thirteen centers have 2 or more clinicians performing brachytherapy with 61% of lead consultants performing > 25 cases (LDR + HDR) in 2016. The number of implants (range), that includes LDR and HDR, performed by individual practitioners in 2016 was > 50 by 21%, 25-50 by 38%, and < 25 by 41%. Eight centers reported a decline in LDR monotherapy case numbers in 2016. Number of center’s performing HDR brachytherapy increased in last five years. Relative uniformity in patient selection is noted, and LDR pre- and post-implant dosimetry adheres to published quality guidelines, with an average post-implant D₉₀ of > 145 Gy in 69% of centers in 2014 and 2015 compared to 63% in 2016. The median CT/US volume ratios were > 0.9 ≤ 1.0 (n = 4), > 1.0 ≤ 1.1 (n = 7), and > 1.1 (n = 2).

Conclusion

There is considerable prostate brachytherapy experience in the UK and Ireland. An apparent fall in LDR case numbers is noted. Maintenance of case numbers and ongoing compliance with published quality guidelines is important to sustain high quality outcomes.

"Super-active surveillance": MRI ultrasound fusion biopsy and ablation for less invasive management of prostate cancer

Multiparametric magnetic resonance imaging (mpMRI) of the prostate has allowed clinicians to better visualize and target suspicious lesions during biopsy. Targeted prostate biopsies give a more accurate representation of the true cancer volume and stage so that appropriate treatment or active surveillance can be selected. Advances in technology have led to the development of MRI and ultrasound fusion platforms used for targeted biopsies, monitoring cancer progression, and more recently for the application of focal therapy. Lesions visualized on mpMRI can be targeted for ablation with a variety of energy sources employed under both local and general anesthesia. Focal ablation may offer an alternative option for treating prostate cancer as compared to the well-established interventions of whole-gland radiation or prostatectomy. Focal ablation may also be an option for patients on active surveillance who wish to be even more "active" in their surveillance. In this review, we describe the advancements and development of fusion biopsies, the rationale behind focal therapy, and introduce focal ablative techniques for indolent prostate cancers ("super-active surveillance"), including cryoablation and focal laser ablation (FLA) and the subsequent MRI/biopsy surveillance.

Effects of interruptions of external beam radiation therapy on outcomes in patients with prostate cancer

INTRODUCTION

To evaluate if interruptions of external beam radiation therapy impact outcomes in men with localized prostate cancer (PCa).

METHODS

We included men with localized PCa treated with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiation therapy (IMRT) of escalated dose (≥74 Gy in 1.8 or 2 Gy fractions) between 1992 and 2013 at an NCI-designated cancer centre. Men receiving androgen deprivation therapy were excluded. The non-treatment day ratio (NTDR) was defined as the number of non-treatment days divided by the total elapsed days of therapy. NTDR was analysed for each National Comprehensive Cancer Network (NCCN) risk group.

RESULTS

There were 1728 men included (839 low-risk, 776 intermediate-risk and 113 high-risk), with a median follow up of 53.5 months (range 12-185.8). The median NTDR was 31% (range 23-71%), translating to approximately 2 breaks (each break represents a missed treatment that will be made up) for 8 weeks of RT with 5 treatments per week. The 75 percentile of NTDR was 33%, translating to approximately 4 breaks, which was used as the cutoff for analysis. There were no significant differences in freedom from biochemical failure, freedom from distant metastasis, cancer specific survival, or overall survival for men with NTDR ≥33% compared to NTDR<33% for each risk group. Multivariable analyses including NTDR, age, race, Gleason score, T stage, and PSA were performed using the proportional hazards regression procedure. NTDR≥33% was not significantly associated with increased hazard ratio for outcomes in each risk group compared to NTDR<33%.

CONCLUSION

Unintentional treatment breaks during dose escalated external beam radiation therapy for PCa did not cause a significant difference in outcomes, although duration of follow up limits the strength of this conclusion.

Hypofractionated radiation therapy for basal and squamous cell skin cancer: A meta-analysis

PURPOSE

To characterize the cosmetic outcomes and local recurrence (LR) rates of various hypofractionated radiation therapy (RT) regimens for skin basal and squamous cell cancers (BCCs/SCCs).

METHODS

A PICOS/PRISMA/MOOSE selection protocol was performed to identify 344 articles published between 1985-2016 evaluating patients with T1-2 N0 SCCs/BCCs treated with definitive RT. Biologically equivalent doses with α/β=3 (BED3s) were calculated. The primary endpoint was post-treatment cosmesis. Mixed effects regression models were used to estimate weighted linear relationships between BED3 and cosmetic outcomes.

RESULTS

A total of 21 studies were identified detailing the treatment of 9729 skin BCC/SCC patients, across seven countries, with external beam RT (n=9255) or brachytherapy (n=474). Median follow-up was 36months (range: 12-77). Median dose was 45Gy/11 fractions (interquartile range: 37.5Gy/6-55Gy/18) at 4Gy/fraction (interquartile range: 2.5-6Gy); most hypofractionated 18.75Gy/1. There was a trend to decreased "good" cosmesis with higher total dose: -3.4% "good" cosmesis/10Gy BED3, p=0.01. Similarly, there was a trend to increased "fair" cosmesis with higher dose: +3.8% "fair" cosmesis/10Gy BED3,p=0.006. At a BED3 of 100Gy, the expected rate of "good" cosmesis is 79% (95% confidence interval: 70%, 88%). Hypofractionated schedules produced similar cosmesis to conventionally fractionated schedules, at the same BED3. Fewer than 8% of patients experienced "poor" cosmesis, independent of dose or fractionation regimen.

CONCLUSION

Hypofractionated RT has favorable cosmesis for patients with skin BCCs/SCCs. We recommend clinicians consider these commonly-used regimens, which all have BED3 of ∼100Gy: 50Gy/15 fractions, 36.75Gy/7 fractions, or 35Gy/5 fractions, as they result in "good" cosmesis in 80% of patients.

Comparison of patient-reported acute urinary and sexual toxicity scores in a 6- versus 2-fraction course of high-dose-rate prostate brachytherapy monotherapy

INTRODUCTION

To identify differences in acute urinary and sexual toxicity between a 6-fraction and 2-fraction high-dose-rate brachytherapy monotherapy regimen and correlate dosimetric constraints to short-term toxicity.

METHODS

A single institution retrospective study of 116 men with prostate cancer treated with HDR monotherapy from 2010 to 2015 was conducted. Eighty-one men had 7.25 Gy × 6-fractions and 35 men had 13.5 Gy × 2-fractions. Patients had two CT-planned implants spaced 1-2 weeks apart. Patient baseline characteristics, International Prostate Symptom Scores (IPSS) and Sexual Health Inventory for Men (SHIM) scores were collected pre-treatment and 3, 6 and 12 months post-implantation. Mixed effect modelling was undertaken to compare baseline, 1-6 month and 7-12 month scores between groups. Poisson regression analysis was performed to correlate dosimetric constraints with acute toxicity.

RESULTS

There was no difference between baseline and post-implantation IPSS scores between 6-fraction and 2-fraction groups. SHIM scores for men treated with 6-fractions had a steeper decline at 1-6 months, but resolved at 7-12 months. Pre-treatment alpha-blocker use correlated with worse short-term acute urinary toxicity. Worsened SHIM score correlated with increasing age, diabetes mellitus and androgen-deprivation therapy. In a dosimetric analysis of outcomes, prostate V150 dose and bladder wall (D01.cc, D1cc, D2cc) dose correlated with increased IPSS score.

CONCLUSION

No increased acute genitourinary or sexual dysfunction has been observed in men when transitioning from 6-fraction to 2-fraction HDR monotherapy. A dosimetric correlation was found between the V150 and bladder wall doses for acute urinary toxicity. Future research should continue to standardize and validate dose constraints for prostate HDR monotherapy patients.

Symptoms predicting health-related quality of life in prostate cancer patients treated with localized radiation therapy

Objective

Patient-reported health-related quality-of-life (HRQOL) measures can provide guidance for treatment decision making, symptom management, and discharge planning. HRQOL is often influenced by the distress experienced by patients from disease or treatment-related symptoms. This study aimed to identify symptoms that can predict changes in HRQOL in men undergoing external beam radiation therapy (EBRT) for nonmetastatic prostate cancer (NMPC).

Methods

Fifty-one men with NMPC scheduled for EBRT were assessed at the baseline, at the midpoint of EBRT, and at the end of EBRT. All participants received 38–42 daily doses of EBRT (five times a week), depending on the stage of their disease. Validated questionnaires were administered to evaluate depressive symptoms, urinary and sexual functions, bowel issues, symptom-related distress, fatigue, and HRQOL. Pearson correlations, repeated-measures ANOVA, and multiple regressions examined the relationships among variables.

Results

Intensification of symptoms and increased symptom-related distress, with a corresponding decline in HRQOL, were observed during EBRT in men with NMPC. Changes in symptoms and symptom distress were associated with changes in HRQOL at the midpoint of EBRT (r=−0.37 to −0.6, P=0.05) and at the end of EBRT (r=−0.3 to −0.47, P=0.01) compared with the baseline. The regression model comprising age, body mass index, Gleason score, T category, androgen-deprivation therapy use, radiation dose received, symptoms (urinary/sexual/bowel problems, fatigue), and overall symptom distress explained 70% of the variance in predicting HRQOL. Urinary problems and fatigue significantly predicted the decline in HRQOL during EBRT.

Conclusion

Identifying specific symptoms that can influence HRQOL during EBRT for NMPC can provide feasible interventional targets to improve treatment outcomes.

The evolution of brachytherapy for prostate cancer

Brachytherapy (BT), using low-dose-rate (LDR) permanent seed implantation or high-dose-rate (HDR) temporary source implantation, is an acceptable treatment option for select patients with prostate cancer of any risk group. The benefits of HDR-BT over LDR-BT include the ability to use the same source for other cancers, lower operator dependence, and - typically - fewer acute irritative symptoms. By contrast, the benefits of LDR-BT include more favourable scheduling logistics, lower initial capital equipment costs, no need for a shielded room, completion in a single implant, and more robust data from clinical trials. Prospective reports comparing HDR-BT and LDR-BT to each other or to other treatment options (such as external beam radiotherapy (EBRT) or surgery) suggest similar outcomes. The 5-year freedom from biochemical failure rates for patients with low-risk, intermediate-risk, and high-risk disease are >85%, 69-97%, and 63-80%, respectively. Brachytherapy with EBRT (versus brachytherapy alone) is an appropriate approach in select patients with intermediate-risk and high-risk disease. The 10-year rates of overall survival, distant metastasis, and cancer-specific mortality are >85%, <10%, and <5%, respectively. Grade 3-4 toxicities associated with HDR-BT and LDR-BT are rare, at <4% in most series, and quality of life is improved in patients who receive brachytherapy compared with those who undergo surgery.

Survival and Complications Following Surgery and Radiation for Localized Prostate Cancer: An International Collaborative Review

BACKGROUND

Evaluation of treatment options for localized prostate cancer (PCa) remains among the highest priorities for comparative effectiveness research. Surgery and radiotherapy (RT) are the two interventions most commonly used.

OBJECTIVE

To provide a critical narrative review of evidence of the comparative effectiveness and harms of surgery and RT in the treatment of localized PCa.

EVIDENCE ACQUISITION

A collaborative critical narrative review of the literature was conducted.

EVIDENCE SYNTHESIS

Evidence to clearly guide treatment choice in PCa remains insufficient. Randomized trials are underpowered for clinically meaningful endpoints and have demonstrated no difference in overall or PCa-specific survival. Observational studies have consistently demonstrated an absolute survival benefit for men treated with radical prostatectomy, but are limited by selection bias and residual confounding errors. Surgery and RT are associated with comparable health-related quality of life following treatment in three randomized trials. Randomized data regarding urinary, erectile, and bowel function show few long-term (>5 yr) differences, although short-term continence and erectile function were worse following surgery and short-term urinary bother and bowel function were worse following RT. There has been recent recognition of other complications that may significantly affect the life trajectory of those undergoing PCa treatment. Of these, hospitalization, the need for urologic, rectoanal, and other major surgical procedures, and secondary cancers are more common among men treated with RT. Androgen deprivation therapy, frequently co-administered with RT, may additionally contribute to treatment-related morbidity. Technological innovations in surgery and RT have shown inconsistent oncologic and functional benefits.

CONCLUSIONS

Owing to underpowered randomized control studies and the selection biases inherent in observational studies, the question of which treatment provides better PCa control cannot be definitively answered now or in the near future. Complications following PCa treatment are relatively common regardless of treatment approach. These include the commonly identified issues of urinary incontinence and erectile dysfunction, and others including hospitalization and invasive procedures to manage complications and secondary malignancies. Population-based outcome studies, rather than clinical trial data, will be necessary for a comprehensive understanding of the relative benefits and risks of each therapeutic approach.

PATIENT SUMMARY

Surgery and radiotherapy are the most common interventions for men diagnosed with prostate cancer. Comparisons of survival after these treatments are limited by various flaws in the relevant studies. Complications are common regardless of the treatment approach.

National Trends and Predictors of Androgen Deprivation Therapy Use in Low-Risk Prostate Cancer

PURPOSE

Androgen deprivation therapy (ADT) is not recommended for low-risk prostate cancer because of its lack of benefit and potential for harm. We evaluated the incidence and predictors of ADT use in low-risk disease.

METHODS AND MATERIALS

Using the National Cancer Database, we identified 197,957 patients with low-risk prostate cancer (Gleason score of 3 + 3 = 6, prostate-specific antigen level <10 ng/mL, and cT1-T2a) diagnosed from 2004 to 2012 with complete demographic and treatment information. We used multiple logistic regression to evaluate predictors of ADT use and Cox regression to examine its association with all-cause mortality.

RESULTS

Overall ADT use decreased from 17.6% in 2004 to 3.5% in 2012. In 2012, 11.5% of low-risk brachytherapy patients and 7.6% of external beam radiation therapy patients received ADT. Among 82,352 irradiation-managed patients, predictors of ADT use included treatment in a community versus academic cancer program (adjusted odds ratio [AOR], 1.60; 95% confidence interval [CI], 1.50-1.71; P<.001; incidence, 14.0% vs 6.0% in 2012); treatment in the South (AOR, 1.51), Midwest (AOR, 1.81), or Northeast (AOR, 1.90) versus West (P<.001); and brachytherapy use versus external beam radiation therapy (AOR, 1.32; 95% CI, 1.27-1.37; P<.001). Among 25,196 patients who did not receive local therapy, predictors of primary ADT use included a Charlson-Deyo comorbidity score of ≥2 versus 0 (AOR, 1.42; 95% CI, 1.06-1.91; P=.018); treatment in a community versus academic cancer program (AOR, 1.61; 95% CI, 1.37-1.90; P<.001); and treatment in the South (AOR, 1.26), Midwest (AOR, 1.52), or Northeast (AOR, 1.28) versus West (P≤.008). Primary ADT use was associated with increased all-cause mortality in patients who did not receive local therapy (adjusted hazard ratio, 1.28; 95% CI, 1.14-1.43; P<.001) after adjustment for age and comorbidity.

CONCLUSIONS

ADT use in low-risk prostate cancer has declined nationally but may remain an issue of concern in certain populations and regions.

Role of radical prostatectomy in metastatic prostate cancer: A review

CONTEXT

Recent demonstration of efficacy with the use of chemohormonal therapy for men with metastatic prostate cancer (mPCa) has expanded the therapeutic options for these patients. Furthermore, multimodal therapy to treat systemic disease in the context of locoregional control has gained increasing interest. Concomitantly, the role of radical prostatectomy (RP) in multimodal treatment for locally advanced prostate cancer is expanding. As a result, there is interest in investigating the potential benefit of cytoreductive RP in mPCa.

OBJECTIVE

To review the literature regarding the role of cytoreductive prostatectomy in the setting of mPCa.

EVIDENCE ACQUISITION

MEDLINE and PubMed electronic databases were queried for English language articles related to patients with mPCa who underwent RP from January 1990 to June 2016. Key words used in our search included cytoreductive prostatectomy, radical prostatectomy, and metastatic prostate cancer. Preclinical, retrospective, and prospective studies were included.

EVIDENCE SYNTHESIS

There are no published randomized control trials examining the role of cytoreduction in mPCa. Local symptoms are high in mPCa and often provide a necessity for palliative procedures with the impact on oncologic outcomes being uncertain. Recently, preclinical and retrospective population-based data suggest a benefit from treatment of the primary tumor in metastatic disease. Potential mechanisms mediating this benefit include prevention of symptomatic local progression and modulation of disease biology, resulting in an improvement in progression-free and overall survival. Current literature supports the feasibility of cytoreductive prostatectomy as it is associated with acceptable side effects that are comparable to RP for high-risk localized disease. In aggregate, these data compel prospective evaluation of the hypothesis that cytoreductive prostatectomy improves the outcome of men with mPCa.

CONCLUSIONS

Cytoreductive prostatectomy in mPCa is a feasible procedure that may improve outcomes for men when combined with multimodal management. Preclinical, translational, and retrospective evidence supports local therapy for metastatic disease. However, currently, evidence is limited and is subject to bias. The results of ongoing prospective randomized trials are required before incorporating this therapeutic strategy into clinical practice.

Splenic irradiation for splenomegaly: A systematic review

Splenic irradiation (SI) is a palliative treatment option for symptomatic splenomegaly (i.e. for pain, early satiety, pancytopenia from sequestration) secondary to hematologic malignancies and disorders. The purpose of the current article is to review the literature on SI for hematologic malignancies and disorders, including: (1) patient selection and optimal technique; (2) efficacy of SI; and (3) toxicities of SI. PICOS/PRISMA methods are used to select 27 articles including 766 courses of SI for 486 patients from 1960 to 2016. The most common cancers treated included chronic lymphocytic leukemia and myeloproliferative disorders; the most common regimen was 10Gy in 1Gy fractions over two weeks, and 27% of patients received retreatment. A partial or complete response (for symptoms, lab abnormalities) was obtained in 85-90% of treated patients, and 30% were retreated within 6-12months. There was no correlation between biologically equivalent dose of radiation therapy and response duration, pain relief, spleen reduction, or cytopenia improvement (r2 all <0.4); therefore, lower doses (e.g. 5Gy in 5 fractions) may be as effective as higher doses. Grade 3-4 toxicity (typically leukopenia, infection) was noted in 22% of courses, with grade 5 toxicity in 0.7% of courses. All grade 5 toxicities were due to either thrombocytopenia with hemorrhage or leukopenia with sepsis (or a combination of both); they were sequelae of cancer and not directly caused by SI. In summary, SI is generally a safe and efficacious method for treating patients with symptomatic splenomegaly.

Identification and prediction of health-related quality of life trajectories after a prostate cancer diagnosis

The aim of our study was to identify physical and mental health-related quality of life (HRQoL) trajectories after a prostate cancer diagnosis and systematically characterize trajectories by behaviours and prognostic factors. Prostate cancer survivors (n = 817) diagnosed between 1997 and 2000 were recruited between 2000 and 2002 into a prospective repeated measurements study. Behavioural/prognostic data were collected through in-person interviews and questionnaires. HRQoL was collected at three post-diagnosis time-points, approximately 2 years apart using the Short Form (SF)-36 validated questionnaire. To identify physical and mental HRQoL trajectories, group-based trajectory modelling was undertaken. Differences between groups were evaluated by assessing influential dropouts (mortality/poor health), behavioural/prognostic factors at diagnosis or during the follow-up. Three trajectories of physical HRQoL were identified including: average-maintaining HRQoL (32.2%), low-declining HRQoL (40.5%) and very low-maintaining HRQoL (27.3%). In addition, three trajectories for mental HRQoL were identified: average-increasing HRQoL (66.5%), above average-declining HRQoL (19.7%) and low-increasing HRQoL (13.8%). In both physical and mental HRQoL, dropout from mortality/poor health differed between trajectories, thus confirming HRQoL and mortality were related. Furthermore, increased Charlson comorbidity index score was consistently associated with physical and mental HRQoL group membership relative to average maintaining groups, while behaviours such as time-varying physical activity was associated with physical HRQoL trajectories but not mental HRQoL trajectories. It was possible to define three trajectories of physical and mental HRQoL after prostate cancer. These data provide insights regarding means for identifying subgroups of prostate cancer survivors with lower or declining HRQoL after diagnosis whom could be targeted for interventions aimed at improving HRQoL.

Men's health supplement use and outcomes in men receiving definitive intensity-modulated radiation therapy for localized prostate cancer

BACKGROUND

Approximately 50% of newly diagnosed cancer patients start taking dietary supplements. Men's health supplements (MHSs), which we define as supplements that are specifically marketed with the terms men's health and prostate health (or similar permutations), are often mislabeled as having potential anticancer benefits.

OBJECTIVE

We evaluated the effects of MHSs on patient outcomes and toxicities in patients who were undergoing definitive intensity-modulated radiation therapy (IMRT) for localized prostate cancer.

DESIGN

This retrospective analysis included patients who were being treated at a National Cancer Institute-designated comprehensive cancer center and consented to have information stored in a prospective database. MHSs were queried online. Outcome measures were freedom from biochemical failure (FFBF) (biochemical failure was defined with the use of the prostate-specific antigen nadir + 2-ng/mL definition), freedom from distant metastasis (FFDM), cancer-specific survival (CSS), and overall survival (OS) as well as toxicities. Kaplan-Meier analysis, log-rank tests, Fine and Gray competing-risk regression (to adjust for patient and lifestyle factors), and Cox models were used.

RESULTS

From 2001 to 2012, 2207 patients were treated with IMRT with a median dose of 78 Gy, and a median follow-up of 46 mo. Of these patients, 43% were low risk, 37% were intermediate risk, and 20% were high risk; 10% used MHSs. MHSs contained a median of 3 identifiable ingredients (range: 0-78 ingredients). Patients who were taking an MHS compared with those who were not had improved 5-y OS (97% compared with 92%, respectively; P = 0.01), but there were no differences in the FFBF (94% compared with 89%, respectively; P = 0.12), FFDM (96% compared with 97%, respectively; P = 0.32), or CSS (100% compared with 99%, respectively; P = 0.22). The unadjusted association between MHS use and improved OS was attenuated after adjustment for patient lifestyle factors and comorbidities. There was no difference in toxicities between the 2 groups (late-grade 3-4 genitourinary <3%; gastrointestinal <4%).

CONCLUSION

The use of MHSs is not associated with outcomes or toxicities.

Prostate Cancer Patients With Unmanaged Diabetes or Receiving Insulin Experience Inferior Outcomes and Toxicities After Treatment With Radiation Therapy

BACKGROUND

The purpose of the study was to determine the effect of type 2 diabetes mellitus (T2DM) on outcomes and toxicities among men with localized prostate cancer receiving definitive radiation therapy.

PATIENTS AND METHODS

We performed a retrospective review of 3217 patients, from 1998 to 2013, subdivided into 5 subgroups: (I) no T2DM; (II) T2DM receiving oral antihyperglycemic agent that contains metformin, no insulin; (III) T2DM receiving nonmetformin oral agent alone, no insulin; (IV) T2DM receiving any insulin; and (V) T2DM not receiving medication. Outcome measures were overall survival, freedom from biochemical failure (BF), freedom from distant metastasis, cancer-specific survival, and toxicities. Kaplan-Meier analysis, log rank tests, Fine and Gray competing risk regression (to adjust for patient and lifestyle factors), Cox models, and subdistribution hazard ratios (sHRs) were used.

RESULTS

Of the 3217 patients, 1295 (40%) were low-risk, 1192 (37%) were intermediate-risk, and 652 (20%) were high risk. The group I to V distribution was 81%, 8%, 5%, 3%, and 4%. The median dose was 78 Gy, and the median follow-up time was 50 (range, 1-190) months. Group V had increased mortality (sHR, 2.1; 95% confidence interval [CI], 0.66-1.54), BF (sHR, 2.14; 0.88-1.83), and cause-specific mortality (sHR, 3.87; 95% CI, 1.31-11). Acute toxicities were higher in group IV versus group I (genitourinary: 38% vs. 26%; P = .01; gastrointestinal: 21% vs. 5%; P = 001). Late toxicities were higher in groups IV and V versus group I (12%-14% vs. 2%-6%; P < .01).

CONCLUSION

Men with T2DM not receiving medication and men with T2DM receiving insulin had worse outcomes and toxicities compared to other patients.

A comparison of robotic arm versus gantry linear accelerator stereotactic body radiation therapy for prostate cancer

Prostate cancer is the most prevalent cancer diagnosed in men in the United States besides skin cancer. Stereotactic body radiation therapy (SBRT; 6–15 Gy per fraction, up to 45 minutes per fraction, delivered in five fractions or less, over the course of approximately 2 weeks) is emerging as a popular treatment option for prostate cancer. The American Society for Radiation Oncology now recognizes SBRT for select low- and intermediate-risk prostate cancer patients. SBRT grew from the notion that high doses of radiation typical of brachytherapy could be delivered noninvasively using modern external-beam radiation therapy planning and delivery methods. SBRT is most commonly delivered using either a traditional gantry-mounted linear accelerator or a robotic arm-mounted linear accelerator. In this systematic review article, we compare and contrast the current clinical evidence supporting a gantry vs robotic arm SBRT for prostate cancer. The data for SBRT show encouraging and comparable results in terms of freedom from biochemical failure (>90% for low and intermediate risk at 5–7 years) and acute and late toxicity (<6% grade 3–4 late toxicities). Other outcomes (eg, overall and cancer-specific mortality) cannot be compared, given the indolent course of low-risk prostate cancer. At this time, neither SBRT device is recommended over the other for all patients; however, gantry-based SBRT machines have the abilities of treating larger volumes with conventional fractionation, shorter treatment time per fraction (~15 minutes for gantry vs ~45 minutes for robotic arm), and the ability to achieve better plans among obese patients (since they are able to use energies >6 MV). Finally, SBRT (particularly on a gantry) may also be more cost-effective than conventionally fractionated external-beam radiation therapy. Randomized controlled trials of SBRT using both technologies are underway.