Treatment at high-volume centers linked to improved survival in high-risk prostate cancer
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Key takeaways:
- Men treated at high-volume centers had significantly longer OS than those treated at low-volume centers.
- The association between treatment volume and OS persisted regardless of academic affiliation.
Men with very high-risk prostate cancer treated at high-volume radiation therapy treatment facilities survived significantly longer than those treated at low-volume centers, according to study results.
The association between higher treatment volume and longer OS persisted regardless of whether men received therapy at academic or nonacademic centers, findings published in JAMA Network Open showed.
Background
Radiation plus androgen deprivation therapy is a first-line treatment option for men with very high-risk prostate cancer. However, the treatment paradigm continues to evolve, both in the manner in which radiation is delivered or through treatment intensification with the addition of chemotherapy or novel androgen-signaling inhibitors, according to study background.
“Treatment for these patients with [very high-risk] prostate cancer may be nuanced, complex and resource intensive — features that may be more readily navigated at high-volume cancer centers,” Nikhil Sebastian, MD, in the radiation oncology department at Winship Cancer Institute, and colleagues wrote. “Numerous studies of patients with other aggressive cancer types have observed that treatment at high-volume facilities is associated with higher rates of long-term overall survival, including those who undergo primary surgery, radiotherapy or chemotherapy.”
Methodology
Sebastian and colleagues conducted a retrospective cohort study to determine whether case volume at radiation therapy facilities affected OS among men with very high-risk prostate cancer.
Investigators analyzed data from U.S.-based facilities that report to the National Cancer Database.
The study cohort included 25,219 men (median age, 71 years; interquartile range, 64-76; 78.7% white) diagnosed with nonmetastatic very high-risk prostate cancer per National Comprehensive Cancer Network criteria.
All men underwent curative-intent radiation therapy and ADT between Jan. 1, 2004, and Dec. 31, 2016.
Researchers defined average cumulative facility volume (ACFV) as the total number of prostate radiotherapy cases at an individual patient’s treatment facility from 2004 until the year of their diagnosis.
“The advantage of ACFV used in this analysis, as opposed to calculating a facility’s patient volume in aggregate across many years, is that it accounts for changes in facility volume and/or expertise that may occur over time during the 12-year study period,” the researchers wrote.
OS served as the study’s primary endpoint.
Key findings
Results showed 6,438 men (25.5%) received treatment at high ACFV centers and 18,781 men (74.5%) received treatment at low ACFV facilities.
After median follow-up of 57.4 months, men treated at high ACFV centers had achieved significantly longer median OS (123.4 months [95% CI, 116.6-127.4] vs. 109 months [95% CI, 106.5-111.2]).
Multivariate analysis revealed a significant association between treatment at high ACFV centers and reduced risk for death (HR = 0.89; 95% CI, 0.84-0.95).
Results also showed a higher estimated rate of 10-year OS among men treated at high-ACFV centers (51.5% vs. 43.9%).
Investigators observed no relationship between facility volume or OS when stratified by academic vs. nonacademic centers. However, in a Kaplan-Meier analysis of OS by subgroups based on facility volume and type, centers with high-volume status appeared associated with improved OS.
“[This suggests] an independent association of facility volume with OS regardless of facility type,” researchers wrote.
Clinical implications
The findings suggest high-volume treatment facilities have expertise and resources that contribute to better outcomes for men with very high-risk prostate cancer, Sebastian and colleagues concluded.
“Further studies should focus on identifying which factors unique to high-volume centers may be accounting for this benefit,” researchers wrote.
Perspective
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Jay Ciezki, MD
In this report by Sebastian and colleagues, we have documentation of the association between high-volume medical centers and better OS for men with very high-risk prostate cancer. The authors suggest some reasons for this observation, including the fact this category of prostate cancer requires more individualization of therapy with several modalities that are more readily available at high-volume centers. Type of center — academic vs. nonacademic — also appeared significantly associated with OS; however, within each center type, higher volume still was associated with improved OS.
The authors’ explanations of the differences are very reasonable, but there are a few other issues that may impact the observations. For example, as the authors rightly state, there have been significant advances in therapy over the study period that are more likely to be adopted first at academic centers. They state that academic/high-volume centers are more likely to adopt these changes because of the availability of resources. Another reason is that they will be more confident ignoring outdated guidelines that rarely keep pace with the latest publications.
The endpoint of OS is important, but it also would be helpful to have an analysis of prostate cancer-specific mortality. The assumption for the difference in OS is that patients treated at low-volume centers have higher prostate cancer-specific mortality, but we are not given the data to prove the point. The authors do their best to account for confounding variables that also may affect OS, such as socioeconomic status and comorbidity burden, but this does not replace an analysis of prostate cancer-specific mortality.
This is an intriguing analysis that deserves more investigation. Despite this, it stands with many other publications on other disease sites that show better outcome when treated at high-volume medical centers.
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Sebastian N, et al. JAMA Netw Open. 2023;doi:10.1001/jamanetworkopen.2023.27637.
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