Survival Rates Higher for Patients with Metastatic Renal Cancer at High-Volume Facilities

Since targeted therapies such as antiangiogenic drugs and mammalian target of rapamycin inhibitors were approved for the treatment of metastatic renal cell carcinoma (mRCC), the five-year survival rate has increased from 57 percent in 1987 to 74 percent from 2006 to 2012. Understanding the differences in efficacy, toxicity and dosing of these new treatments is associated with better clinical outcomes. Often, it is high-volume facilities that have dedicated genitourinary medical oncologists who have the resources and expertise to effectively administer new treatments.

In surgical oncology, it is well established that long-term survival rates are higher at high-volume facilities. In radiation oncology, evidence is also emerging that shows improved overall survival in patients treated at high-volume facilities. However, there is only limited data on the volume-outcome association in hematology-oncology managed cancers, especially advanced solid tumors.

Cleveland Clinic Cancer Center researchers investigated whether this association exists for mRCC patients using data from the National Cancer Database (NCDB) Participant Use Data File, which captures 70 percent of newly diagnosed cancer cases in the U.S., making it the world’s largest cancer registry. The results appear in Urologic Oncology.

“With many metastatic renal cancer patients treated mainly by medical oncologists, we wanted to find out if outcomes are affected by facility size in the targeted therapy era,” says Yu-Wei Chen, MD, MS, a study investigator and internal medicine resident at Cleveland Clinic.

Database characteristics

From the NCDB, the investigators identified 31,329 mRCC patients from 2006 to 2015, of which 36.2 percent were treated at academic medical centers. The median age at diagnosis was 64, and 66 percent were male. During the first treatment course, patients at high-volume facilities were more likely to have targeted therapy (TT) (49.8 versus 46.1 percent of patients at low-volume facilities), cytoreductive nephrectomy (CN) (36.9 versus 24 percent) and metastasectomy (18.9 versus 9.7 percent). Overall, 26.8 percent of patients had radiation, with no significant difference between the two groups.

Regarding disease status, patients at high-volume facilities had higher rates of T3/T4 mRCC (39.4 versus 32.4 percent), N1 disease (31 versus 30.3 percent) and Fuhrman grade 3 and 4 disease (37.5 versus 28 percent). They had lower Charlson comorbidity scores.

Results

The 95th percentile was chosen for analysis. To reduce selection bias, baseline characteristic differences were adjusted with inverse propensity-score weighting-adjusted Kaplan-Meier analysis.

The survival difference was significant: The one-, two- and three-year survival rates at higher volume versus lower volume facilities were 41, 26 and 19 percent vs. 36, 22 and 16 percent. Even patients with stage 4 mRCC had higher survival rates.

“As RCC is a rare disease, a higher volume facility allows for more specialization and disease-specific knowledge of the subtleties of RCC. This translates into better patient outcomes given the experience of not just the doctors, but the whole team of caregivers,” says Brian Rini, MD, who leads Cleveland Clinic Cancer Center’s Genitourinary Program.

The study raises the issue of how to address the disparity between low- and high-volume facilities to improve care for all medical oncology patients. “It’s worth conducting further research to try to reduce the gap, but there’s no simple solution. Not only do high-volume facilities have more resources but so do their patients who can travel farther to access care,” says Dr. Chen.

Moving into a new treatment era

Treatment for mRCC is evolving quickly. With positive clinical trial outcomes for novel immunotherapy agents reported over the past few years, they have become the new standard of care. As a cancer with immunogenic properties, RCC has responded well to immunotherapy. This raises the question of whether outcomes for immunotherapy treatment will also be better at high-volume facilities. Cleveland Clinic may conduct a follow-up study to find out whether the survival disparity exists for this new type of treatment, reports Dr. Chen.