Investigators who studied a “real world” sample of Medicare patients with metastatic renal cell carcinoma (mRCC) found that patients who received targeted therapies for their cancer experienced modest improvements in survival compared with those who received non-targeted therapies.
Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare data from 2000 to 2013, Pengxiang Li, PhD, of the University of Pennsylvania in Philadelphia, and colleagues selected a sample of 1015 patients with clear cell mRCC at the time of diagnosis who received targeted or non-targeted treatment. Targeted therapy was associated with a 22% decreased risk of all-cause mortality and 23% decreased risk of RCC-specific mortality compared with non-targeted treatment, the investigators reported in JAMA Network Open.
The median overall survival advantage in the targeted therapy group was 3 months, according to an instrumental variable analysis estimate. The overall survival improvements associated with targeted therapy vs non-targeted therapy were 8% (44% vs 36%) at 1 year, 7% (25% vs 18%) at 2 years, 5% (15% vs 10%) at 3 years, according to the investigators.
Dr Li and colleagues noted that patients’ median survival times were shorter than reported for patients in randomized trials of targeted treatments. “One potential explanation is that clinical trials in advanced RCC typically include both individuals who are experiencing progression of disease initially diagnosed at an earlier stage and those with late-stage diagnoses, whereas our sample was identified through SEER staging data and included only patients with stage IV disease at diagnosis,” they wrote.
In addition, the authors stated that the Medicare population, by definition, is older and/or disabled, and clinical trials typically enroll patients who are younger and healthier than the general population of patients with cancer.
“Targeted therapies were associated with modest survival advantages despite a treatment group with more medical complexity, likely reflecting appropriateness for an expanded population of patients,” the investigators concluded.
In a discussion of implications for clinical practice, Dr Li and colleagues noted that the demographic and clinical characteristics of the patients observed in their “real-world” sample suggest that targeted therapies likely offered new options for patients who might have foregone therapy in the era before targeted therapy because of toxicity concerns, “and our results underscore that survival benefits may vary when treatments are administered to a broader population of patients. This finding highlights the need for patient-centered conversations that focus on potential benefits and risks in the context of the diverse personal circumstances, values, and goals of individuals treated in real-world settings.”
The authors acknowledged that their focus on a Medicare population was among their study’s limitations. As a result, their findings may not be generalizable to younger or healthier populations. Another limitation was a lack of access to fine-grained details of patient treatment regimens. Consequently, their findings “do not offer insight into whether the dosing or duration of treatment received by the individuals in our study was consistent with clinical trial regimens.”
The study population had a mean age of 71.2 years. Of the 1015 patients, 392 were women (39%) and 623 were men (61%); 641 patients (63%) received targeted therapy and 374 (37%) received non-targeted therapy. The targeted therapy group had a larger proportion of disabled patients (individuals younger than 65 years who were eligible for Medicare because of disability).
Li P, Jahnke J, Pettit AR, et al. Comparative survival associated with the use of targeted vs nontargeted therapy in Medicare patients with metastatic renal cell carcinoma. JAMA Netw Open. 2019;2(6):e195806.