The use of targeted therapies appears to be associated with longer overall survival (OS) and renal cell carcinoma (RCC)-specific survival compared with the use of nontargeted therapies among Medicare beneficiaries with metastatic RCC, according to a new observational study of targeted versus nontargeted therapy for metastatic RCC. The study, which was published in JAMA, found across a cohort of 1015 patients that the estimated OS improvements with targeted therapies were statistically significant (8% at 1 year, 7% at 2 years, and 5% at 3 years) even though the patients receiving targeted therapies had more comorbid conditions.
“This confirms that less-toxic treatments are allowing a broader range of patients the opportunity to be treated. Median survival in our real-world study was substantially less than in clinical trials, but some people did do quite well and our data were from the earlier targeted therapy era. Treatments continue to improve,” said corresponding author of the study Jalpa A. Doshi, PhD, who is a professor of medicine at the University of Pennsylvania’s Perelman School of Medicine, Philadelphia, Pennsylvania.
She said when there’s a paradigm shift in treatment, as there has been with the introduction of targeted therapies for advanced kidney cancer, it can be hard to determine what the true advantages are in a real-world clinical practice. She said a lot of factors muddy the waters. “It’s tempting to look at study headlines, but the details of the methods can be really important. When we did a traditional analysis, we didn’t find a statistically significant advantage for targeted therapies over nontargeted therapies. But when we used more sophisticated methods, which allowed us to control for unmeasured variables that might confound the results, the differences were significant,” Dr Doshi told Cancer Therapy Advisor.
Dr Doshi and colleagues used Surveillance, Epidemiology, and End Results (SEER)–Medicare data from 2000 to 2013 and examined patients with stage IV clear cell RCC. The mean age of the patients was 71.2 years and 392 (39%) were women. In this cohort, 374 (37%) received nontargeted therapies and 641 (63%) received targeted therapies. The targeted therapy group had more patients who were aged older than 75 years and higher comorbidity index and disability scores compared with the nontargeted therapy group. The researchers found in both groups that metastatic lung disease was the most common. However, there was a greater percentage of patients receiving targeted therapy who had metastatic bone disease.
The median follow-up from the first treatment was 8 months (range, 3-20 months) and the researchers found the median unadjusted OS was 8.7 months for the targeted therapy group versus 7.2 months for the nontargeted therapy group. The RCC-specific survival also favored the targeted group (13.2 months vs 10.5 months for the nontargeted therapy group). “As oncologists know, real-world practice is complex, and the more information we have about treatment outcomes in broader populations, the better equipped people are to make treatment decisions that are right for them,” said Dr Doshi.