ASCO GU 2018: The Impact of Facility Case Volume on Overall Survival in Patients with Metastatic Renal Cell Carcinoma in The Targeted Therapy Era
As has been assessed in many other disease spaces, there is growing evidence that high-volume centers have better long-term outcomes in the management of these complex cases. In this study, the authors aim to investigate whether higher facility case volume (FCV) is associated with improved overall survival (OS) for mRCC. They completed a population-level analysis using the National Cancer Database (NCDB) - while this database has been used frequently in the past few years, it is significantly limited by lack of cause-specific survival data – hence, all outcomes are based on overall survival.
FCV was determined by the total cases of renal cell carcinoma (metastatic and non-metastatic) at each treating facility. Multivariable Cox regression model was used to investigate the association between FCV and OS. Covariates adjusted for were treatment modalities [targeted therapy, cytoreductive nephrectomy, and metastasectomy], tumor characteristics and patient sociodemographics. Model is also adjusted for age, race, sex, insurance status, Charlson comorbidity score, tumor stage, nodal status, histology type, year of diagnosis, and zip code-level socioeconomic data (income, education level and residence type).
They identified 18,571 mRCC patients in the database between 2006-2012; mean follow-up time was 13.2 months (median: 6; interquartile range: 2.3-17.9).
On multivariable analysis, after adjusting for baseline characteristics including treatment modalities, every increment of 100 FCV of the treating facility was associated with improved OS (AHR: 0.99, 95 CI: 0.98-0.99, p-value: 0.003). While significant, this HR is not that impressive.
FCV was dichotomized at increasing percentiles (50th, 80th, 85th, 90th, and 95th). Improved OS was observed when high FCV was defined at 90th percentile (47 cases/year; AHR: 0.96, 95% CI: 0.92-0.99, p-value: 0.02) and 95th percentile (68 cases/year; AHR: 0.95, 95% CI: 0.91-0.98, p-value: 0.04) but not at 50th (8 cases/year), 80th (30 cases/year) or 85th percentile (38 cases/year).
In contrast, the HR for TT, cytoreductive nephrectomy and metastatectomy were much more significant – HR 0.48 to 0.74. More importantly, academic centers had improved OS compared to community hospitals (HR 0.93, p<0.0001).
It should be noted that even 90th and 95th percentile centers saw 47-68 cases of metastatic and non-metastatic cases per year – how many of those were localized RCC is uncertain, but I suspect a large proportion of those. Is it relevant if a center sees a lot of localized RCC to the management of mRCC?
Regardless, the authors conclude that treatment at hospitals with higher RCC case volme is associated with improved OS for patients diagnosed with mRCC in the targeted therapy era.
However, the model and patient selection, in my mind, is somewhat flawed.
It should be noted that an almost identical analysis was completed by the Fox Chase group (GU ASCO 2018, Abstract 594, Daniel Geynisman). Interestingly, they identified ~44000 cases of mRCC from 2006-2013, which doesn’t quite match with the number of cases identified in this abstract. Which group is correct?
Limitations / Discussion Points:
1. As this abstract is about mRCC, it is unclear why they based FCV on non-metastatic RCC cases.
2. Overall survival is only one surrogate of response. CSS and PFS are not captured in this study. 3. Unfortunately, higher volume centers likely see more complex cases and may have artificially lower OS.
Speaker: Yu-Wei Chen, MD
Co-Authors: Katherine Tullio, Moshe Chaim Ornstein, Petros Grivas, Jorge A. Garcia, Brian I. Rini
Institution(s): Cleveland Clinic, Cleveland, OH; Cleveland Clinic Taussig Cancer Institute, Cleveland, OH
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA