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

Trends and variation in the use of radiotherapy in non-metastatic prostate cancer: A 12-year nationwide overview from the Netherlands

PURPOSE

This population-based study describes nationwide trends and variation in the use of primary radiotherapy for non-metastatic prostate cancer in The Netherlands in 2008-2019.

METHODS

Prostate cancer patients were selected from the Netherlands Cancer Registry (N = 103,059). Treatment trends were studied over time by prognostic risk groups. Multilevel analyses were applied to identify variables associated with external beam radiotherapy (EBRT) and brachy-monotherapy versus no active treatment in low-risk disease, and EBRT versus radical prostatectomy in intermediate and high-risk disease.

RESULTS

EBRT use remained stable (5-6%) in low-risk prostate cancer and increased from 21% to 32% in intermediate-risk, 37% to 45% in high-risk localized and 50% to 57% in high-risk locally advanced disease. Brachy-monotherapy decreased from 19% to 6% and from 15% to 10% in low and intermediate-risk disease, respectively, coinciding an increase of no active treatment from 55% to 73% in low-risk disease. Use of EBRT or brachy-monotherapy versus no active treatment in low-risk disease differed by region, T-stage and patient characteristics. Hospital characteristics were not associated with treatment in low-risk disease, except for availability of brachy-monotherapy in 2008-2013. Age, number of comorbidities, travel time for EBRT, prognostic risk group, and hospital characteristics were associated with EBRT versus prostatectomy in intermediate and high-risk disease.

CONCLUSION

Intermediate/high-risk PCa was increasingly managed with EBRT, while brachy-monotherapy in low/intermediate-risk PCa decreased. In low-risk PCa, the no active treatment-approach increased. Variation in treatment suggests treatment decision related to patient/disease characteristics. In intermediate/high-risk disease, variation seems furthermore related to the treatment modalities available in the diagnosing hospitals.

Risk of severe late toxicity after radiotherapy following radical prostatectomy - a nationwide study

BACKGROUND

Severe side-effects are rare but may occur years after radiation therapy following radical prostatectomy. We sought to estimate the long-term risks of severe late toxicities in an unselected, nationwide, cohort.

METHODS

The study population comprised all men undergoing radical prostatectomy between 1997-2016 in the Prostate Cancer database Sweden (PCBaSe) (n=40,962). By (1:2) matching, two cohorts were created: 2789 men exposed to postoperative radiation and 5578 nonexposed men with comparable age, comorbidities and year of surgery. Cumulative incidences and rate ratios were calculated for the following outcomes: symptoms and interventions of the urinary or intestinal tract demanding inpatient care, secondary malignancies and non-prostate cancer mortality.

RESULTS

The largest differences were seen for late toxicities affecting the urinary tract. The 10-year cumulative incidences among those exposed to postoperative radiation versus the surgery only group were: 17.8% versus 10.5% for procedures of the urinary tract (difference 7.3%, 95% confidence interval [CI] 4.4 to 10.3; relative risk [RR] 1.74, 95% CI 1.47 to 2.05); 6.0% versus 1.2% for hematuria (difference 4.8%, 95% CI 3.1 to 6.5; RR 6.50 95% CI 4.31 to 10.10); and 2.4% versus 1.1% for bladder cancer (difference 1.4%, 95% CI 0.4 to 2.3; RR 2.71 95% CI 1.72 to 4.33). The groups were similar regarding intestinal toxicity, other secondary malignancies, and non-prostate cancer mortality. Adjustments for preoperative tumor risk factors did not importantly affect the rate ratios.

CONCLUSION

Severe late toxicity after postoperative radiation following radical prostatectomy predominately affects the bladder and can appear many years after radiotherapy.

Evaluation of Hypofractionated Radiation Therapy Use and Patient-Reported Outcomes in Men With Nonmetastatic Prostate Cancer in Australia and New Zealand

IMPORTANCE

Randomized clinical trials in prostate cancer have reported noninferior outcomes for hypofractionated radiation therapy (HRT) compared with conventional RT (CRT); however, uptake of HRT across jurisdictions is variable.

OBJECTIVE

To evaluate the use of HRT vs CRT in men with nonmetastatic prostate cancer and compare patient-reported outcomes (PROs) at a population level.

DESIGN, SETTING, AND PARTICIPANTS

Registry-based cohort study from the Australian and New Zealand Prostate Cancer Outcomes Registry (PCOR-ANZ). Participants were men with nonmetastatic prostate cancer treated with primary RT (excluding brachytherapy) from January 2016 to December 2019. Data were analyzed in March 2021.

EXPOSURES

HRT defined as 2.5 to 3.3 Gy and CRT defined as 1.7 to 2.3 Gy per fraction.

MAIN OUTCOMES AND MEASURES

Temporal trends and institutional, clinicopathological, and sociodemographic factors associated with use of HRT were analyzed. PROs were assessed 12 months following RT using the Expanded Prostate Cancer Index Composite (EPIC)-26 Short Form questionnaire. Differences in PROs were analyzed by adjusting for age and National Comprehensive Cancer Network risk category.

RESULTS

Of 8305 men identified as receiving primary RT, 6368 met the inclusion criteria for CRT (n = 4482) and HRT (n = 1886). The median age was 73.1 years (IQR, 68.2-77.3 years), 2.6% (168) had low risk, 45.7% (2911) had intermediate risk, 44.5% (2836) had high-/very high-risk, and 7.1% (453) had regional nodal disease. Use of HRT increased from 2.1% (9 of 435) in the first half of 2016 to 52.7% (539 of 1023) in the second half of 2019, with lower uptake in the high-/very high-risk (1.9% [4 of 215] to 42.4% [181 of 427]) compared with the intermediate-risk group (2.2% [4 of 185] to 67.6% [325 of 481]) (odds ratio, 0.26; 95% CI, 0.15-0.45). Substantial variability in the use of HRT for intermediate-risk disease remained at the institutional level (median 53.3%; range, 0%-100%) and clinician level (median 57.9%; range, 0%-100%) in the last 2 years of the study period. There were no clinically significant differences across EPIC-26 urinary and bowel functional domains or bother scores.

CONCLUSIONS AND RELEVANCE

In this cohort study, use of HRT for prostate cancer increased substantially from 2016. This population-level data demonstrated clinically equivalent PROs and supports the continued implementation of HRT into routine practice. The wide variation in practice observed at the jurisdictional, institutional, and clinician level provides stakeholders with information that may be useful in targeting implementation strategies and benchmarking services.

Characterizing Surgical and Radiotherapy Outcomes in Non-metastatic High-Risk Prostate Cancer: A Systematic Review and Meta-Analysis

Background Identifying the optimal management of high-risk non-metastatic prostate cancer (PCa) is an important public health concern, given the large burden of this disease. We performed a meta-analysis of studies comparing PCa-specific mortality (CSM) among men diagnosed with high-risk non-metastatic PCa who were treated with primary radiotherapy (RT) and radical prostatectomy (RP). Methods Medline and Embase were searched for articles between January 1, 2005, and February 11, 2020. After title and abstract screening, two authors independently reviewed full-text articles for inclusion. Data were abstracted, and a modified version of the Newcastle-Ottawa Scale, involving a comprehensive list of confounding variables, was used to assess the risk of bias. Results Fifteen studies involving 131,392 patients were included. No difference in adjusted CSM in RT relative to RP was shown (hazard ratio, 1.02 [95% confidence interval: 0.84, 1.25]). Increased CSM was found in a subgroup analysis comparing external beam radiation therapy (EBRT) with RP (1.35 [1.10, 1.68]), whereas EBRT combined with brachytherapy (BT) versus RP showed lower CSM (0.68 [0.48, 0.95]). All studies demonstrated a high risk of bias as none fully adjusted for all confounding variables. Conclusion We found no difference in CSM between men diagnosed with non-metastatic high-risk PCa and treated with RP or RT; however, this is likely explained by increased CSM in men treated with EBRT and decreased CSM in men treated with EBRT + BT studies relative to RP. High risk of bias in all studies identifies the need for better data collection and confounding control in the PCa research.

Population-Level Uptake of Moderately Hypofractionated Definitive Radiation Therapy in the Treatment of Prostate Cancer

PURPOSE

Recent evidence shows the noninferiority of hypofractionated radiation therapy regimens compared with conventional regimens in the treatment of prostate cancer (PCa). Hypofractionation has benefits for both the patient and health care system, because of the shorter treatment duration. Despite this advantage, the uptake of hypofractionation can be slow. Here we investigate the factors influencing the changing use of moderate hypofractionation (HypoRT) for the treatment of PCa.

METHODS AND MATERIALS

We conducted a population-based, retrospective, consecutive cohort study using the 2014 to 2018 Outpatient Radiation Oncology Data from public and private treatment facilities in New South Wales, Australia. Included participants had a PCa diagnosis of any risk, and they completed curative-intent external beam radiation therapy without treatment to lymph nodes. Factors potentially affecting use of HypoRT were examined using a 3-level hierarchical logistic regression model. The effects were reported using adjusted, median, or interval odds ratios.

RESULTS

The study included 4915 patients. Of these, 4053 patients (82.5%) received conventional fractionation, and 862 patients (17.5%) received HypoRT. HypoRT utilization increased from 5.2% in 2014 to 40.3% in 2018. The treating radiation oncologist, treatment facility, and increasing distance to treatment centers had the greatest influence on HypoRT uptake. The main limitation was the lack of stratification by PCa risk categorization.

CONCLUSIONS

Although HypoRT uptake has considerably increased between 2014 and 2018, it remains variable among facilities and treating radiation oncologists. Strategies are being explored to reduce inter-clinician variability.

Acute toxicity of 4-week versus 5-week hypofractionated radiotherapy in localised prostate cancer

Aim:

To compare the acute radiation-induced bowel and bladder toxicities of two hypofractionated radiotherapy (HFRT) regimens in localised prostate cancer (PCa).

Materials and methods:

This trial consists of patients with histologically confirmed stage T1-T3aN0M0 PCa, a prostate-specific antigen concentration of 40 ng/mL or lower, and Eastern Cooperative Oncology Group performance status of 0–2. Participants were randomly assigned (1:1) to 56 Gy in 16 fractions over 4 weeks (arm A) or 70·2 Gy in 26 fractions over 5 weeks (arm B). Acute bowel and bladder toxicities were assessed using Radiation Therapy Oncology Group criteria.

Results:

Between June 2018 and December 2019, 40 patients were randomly assigned to treatment with 4-week (n = 20) and 5-week HFRT (n = 20). In the third month after completion of radiotherapy, the cumulative incidence of acute bowel and bladder toxicities of arms A and B was 20 versus 5% and 70 versus 85%, respectively. The cumulative incidence of grade 2 or worse bowel and bladder toxicities of the 5-week regimen was non-inferior to 4-week HFRT [bowel toxicity: 5% (arm A) versus 5% (arm B), bladder toxicity: 50% (arm A) versus 60% (arm B), p = 0·52).

Findings:

The 5-week regimen of HFRT is non-inferior to 4-week HFRT in terms of acute bowel and bladder toxicities.

The Value of Real-World Data in Understanding Prostate Cancer Risk and Improving Clinical Care: Examples from Swedish Registries

Simple Summary

Real-world data (RWD), i.e., data reflecting normal clinical practice collected outside the constraints of randomised controlled trials, provide important insights into our understanding of prostate cancer and its management. Clinical cancer registries are an important source of RWD. Depending on their scope and the potential linkage to other data sources, registry-based data can be utilised to address a variety of questions including risk factors, healthcare utilisation, treatment effectiveness, adverse effects, disparities in healthcare access, quality of care and healthcare economics. This review describes the various registry-based RWD sources for prostate cancer research in Sweden (namely the National Prostate Cancer Register, the Prostate Cancer data Base Sweden (PCBaSe) and the Patient-overview Prostate Cancer) and documents their utility for better understanding prostate cancer aetiology and improving clinical care.

Abstract

Real-world data (RWD), that is, data from sources other than controlled clinical trials, play an increasingly important role in medical research. The development of quality clinical registers, increasing access to administrative data sources, growing computing power and data linkage capacities have contributed to greater availability of RWD. Evidence derived from RWD increases our understanding of prostate cancer (PCa) aetiology, natural history and effective management. While randomised controlled trials offer the best level of evidence for establishing the efficacy of medical interventions and making causal inferences, studies using RWD offer complementary evidence about the effectiveness, long-term outcomes and safety of interventions in real-world settings. RWD provide the only means of addressing questions about risk factors and exposures that cannot be “controlled”, or when assessing rare outcomes. This review provides examples of the value of RWD for generating evidence about PCa, focusing on studies using data from a quality clinical register, namely the National Prostate Cancer Register (NPCR) Sweden, with longitudinal data on advanced PCa in Patient-overview Prostate Cancer (PPC) and data linkages to other sources in Prostate Cancer data Base Sweden (PCBaSe).

A-blockers for the management of lower urinary tract symptoms in patients with prostate cancer treated with external beam radiotherapy: a randomized controlled study

BACKGROUND

This is a prospective study aiming to assess the efficacy of α-blockers in treating radiotherapy-induced symptoms of the lower urinary tract and its possible prophylactic role on acute urinary retention (AUR) in patients undergoing radical external beam radiotherapy (EBRT) for localized prostate cancer (PCa).

METHODS

Overall, 108 patients with localized PCa were recruited and randomly assigned in to two groups; 54 patients of Group 1 received tamsulosin 0.4 mg once daily with the initiation of EBRT and for 6 months and 54 patients of Group 2 served as the control group. All patients received radical EBRT and had post-void volume (Vres) assessment. The International Prostate Symptom Score (IPSS) questionnaire and evaluation of episodes of AUR were performed after the end of radiotherapy, at 3 and at 6 months.

RESULTS

The incidence of AUR was significantly (p = 0.027) lower in group 1 compared to group 2. No independent predictive factors for AUR were identified in regression analysis. The IPSS changes in univariate and multivariate analysis at 3 months showed significant correlation with α-blockers only, while at 6 months showed significant correlation with Vres assessments (at 3 and 6 months) and with α-blockers. Side effects due to medication were mild and none of the patients discontinued the treatment.

CONCLUSIONS

The selective use of α-blocker appears to prevent AUR in EBRT-treated patients. Although the administration of α-blockers might relieve patient-reported symptoms, there are no established independent predictive factors to distinguish patients who may benefit.

Comparison of Survival Between Hypofractionated and Conventional Radiotherapy in Clinically Localized Prostate Cancer: A Single-Center Retrospective Cohort

Background: Prostate cancer (pCa) is the most frequently diagnosed visceral cancer among men. The main role of radical prostatectomy and external-beam radiation therapy (EBRT) in the management of patients with localized pCa has been established. Objectives: This study aims at comparing the clinical outcomes of hypofractionated versus conventional EBRT in the definitive management of patients with localized pCa. Methods: From 2013 to 2019, a consecutive series of patients with localized pCa was treated with conventional (74 Gy at 2 Gy fractions) or hypofractionated (70.2 Gy at 2.7 Gy fractions) radiotherapy schedules, using 3-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), respectively. The impact of the fractionation schedule on biochemical or clinical relapse-free survival (bc-RFS) and overall survival (OS) was assessed. Results: The median follow-up was 42 months (range: 8 - 81 months). Among 170 patients, 81 were treated with conventional and 89 with the hypofractionated schedule. The patient characteristics between groups were comparable. The mean bc-RFS of patients in conventional and hypofractionated groups was 34.9 and 35.4 months, respectively (confidence interval (CI) 95%: 34.5 - 35.7, P = 0.25). Accordingly, the mean OS of patients in conventional and hypofractionated groups was 34.6 and 38.6 months, respectively (CI 95%: 37.3 - 38.6, P = 0.04). The sub-analysis showed that the OS benefit of hypofractionated schedule was limited to intermediate- and high-risk groups with a trend toward significance (CI 95%: 0.02 - 1.46, P = 0.054). Conclusions: Hypofractionation had OS benefit over the conventional schedule for definitive radiotherapy of localized pCa. This benefit was limited to patients with intermediate- and high-risk pCa.

MR-PROTECT: Clinical feasibility of a prostate MRI-only radiotherapy treatment workflow and investigation of acceptance criteria

BACKGROUND

Retrospective studies on MRI-only radiotherapy have been presented. Widespread clinical implementations of MRI-only workflows are however limited by the absence of guidelines. The MR-PROTECT trial presents an MRI-only radiotherapy workflow for prostate cancer using a new single sequence strategy. The workflow incorporated the commercial synthetic CT (sCT) generation software MriPlanner™ (Spectronic Medical, Helsingborg, Sweden). Feasibility of the workflow and limits for acceptance criteria were investigated for the suggested workflow with the aim to facilitate future clinical implementations.

METHODS

An MRI-only workflow including imaging, post imaging tasks, treatment plan creation, quality assurance and treatment delivery was created with questionnaires. All tasks were performed in a single MR-sequence geometry, eliminating image registrations. Prospective CT-quality assurance (QA) was performed prior treatment comparing the PTV mean dose between sCT and CT dose-distributions. Retrospective analysis of the MRI-only gold fiducial marker (GFM) identification, DVH- analysis, gamma evaluation and patient set-up verification using GFMs and cone beam CT were performed.

RESULTS

An MRI-only treatment was delivered to 39 out of 40 patients. The excluded patient was too large for the predefined imaging field-of-view. All tasks could successfully be performed for the treated patients. There was a maximum deviation of 1.2% in PTV mean dose was seen in the prospective CT-QA. Retrospective analysis showed a maximum deviation below 2% in the DVH-analysis after correction for rectal gas and gamma pass-rates above 98%. MRI-only patient set-up deviation was below 2 mm for all but one investigated case and a maximum of 2.2 mm deviation in the GFM-identification compared to CT.

CONCLUSIONS

The MR-PROTECT trial shows the feasibility of an MRI-only prostate radiotherapy workflow. A major advantage with the presented workflow is the incorporation of a sCT-generation method with multi-vendor capability. The presented single sequence approach are easily adapted by other clinics and the general implementation procedure can be replicated. The dose deviation and the gamma pass-rate acceptance criteria earlier suggested was achievable, and these limits can thereby be confirmed. GFM-identification acceptance criteria are depending on the choice of identification method and slice thickness. Patient positioning strategies needs further investigations to establish acceptance criteria.