Longer OS Observed for N1 Prostate Cancer Treated at Facilities with High Radiation Case Volume

February 1, 2021
Hannah Slater

To evaluate the association between radiation facility case volume and OS among men with lymph node–positive prostate cancer who receive external beam radiation therapy, this cohort study assessed men diagnosed with T1N1M0 to T4N1M0 disease treated with curative-intent radiotherapy and androgen deprivation therapy.

A study published in JAMA Network Open revealed that for men with N1 prostate cancer undergoing external beam radiation therapy (EBRT) with concomitant androgen deprivation therapy (ADT), treatment at a facility with high radiation case volume, regardless of academic affiliation, was correlated with longer overall survival (OS).

“Numerous studies have shown that patients with cancer who are treated at high-volume facilities have higher rates of long-term survival, including those who undergo primary surgery, radiation, or chemotherapy,” wrote the study authors, led by Sagar A. Patel, MD. “Given the complexity of management of N1 prostate cancer, we hypothesized that men treated at high-volume centers would have improved OS compared with those treated at low-volume centers.”

To evaluate the association between radiation facility case volume and OS among men with N1 prostate cancer, this cohort study assessed men diagnosed with T1N1M0 to T4N1M0 prostate cancer treated with curative-intent EBRT and ADT between January 2004 and December 2016 at facilities in the United States reporting to the National Cancer Database. Overall, 1899 men met the inclusion criteria and were enrolled in the study.

Treatment at a center with high versus low average cumulative facility volume (ACFV) was defined as the total number of prostate radiation cases at a given treatment facility from 2004 until the year of the respective patient’s diagnosis. The ideal ACFV cutoff point was found to be 66.4 patients per year.

For patients treated at high-ACFV centers, the median OS was 111.1 months (95% CI, 101.5-127.9) compared with 92.3 months (95% CI, 87.7-103.9) in low-ACFV centers (P = .01). Moreover, on multivariate analysis, treatment at a center with low-ACFV was associated with increased risk of death (HR, 1.22; 95% CI, 1.02-1.46, P = .03) when compared with treatment at a center with high-ACFV. Following propensity score-based adjustment, these results persisted.

“Similar to our cohort of patients with N1 prostate cancer, this association has been demonstrated in other aggressive disease types, including locally advanced lung and head and neck cancers, muscle invasive bladder cancer, and high-risk prostate cancer,” noted the authors.

According to investigators, there are other aspects of care at high-volume centers that could explain the higher long-term survival rate observed in men with N1 prostate cancer. For example, high-volume facilities may contain optimal multidisciplinary care in the same hospital and center. Given that treatment of men with advanced prostate cancer requires close collaboration between a multitude of disciplines, it is possible that high-volume centers more often have close collaboration and workflows between these disciplines.

Moreover, high-volume centers might utilize advanced molecular imaging—such as fluciclovine, choline, or prostate-specific membrane antigen PET—more frequently, which may detect occult nodal disease, resulting in stage migration and better outcomes versus those who have more advanced nodal disease burden that is detectable by conventional imaging. Clinical health care providers at high-volume facilities, including advanced practitioners and nurses, might also have more experience with managing acute toxic effects typically associated with aggressive local and systemic therapy.

“Considering that definitive EBRT with ADT is an increasingly preferred treatment option for these men, our results are hypothesis-generating, and further studies should focus on identifying which factors unique to high-volume centers may be responsible for this benefit,” the authors concluded.

Reference:

Patel SA, Goyal S, Liu Y, et al. Analysis of radiation facility volume and survival in men with lymph node–positive prostate cancer treated with radiation and androgen deprivation therapy. JAMA Netw Open. 2020;3(12):e2025143. doi:10.1001/jamanetworkopen.2020.25143