Survival Outcomes and Practice Trends for Off-Label Use of Adjuvant Targeted Therapy in High-Risk Locoregional Renal Cell Carcinoma - Beyond the Abstract

For this manuscript, we examined the survival outcomes and national practice trends for the use of off-label adjuvant targeted therapy in high-risk locoregional renal cell carcinoma. In 2017 the FDA approved sunitinib for this indication. However, due to mixed results from the relevant randomized controlled trials, the appropriateness of this treatment strategy remains unclear.

Utilizing the National Cancer Database, we found that 5.04% of patients with high-risk locoregional renal cell carcinoma received off-label adjuvant targeted therapy from 2006 – 2015. The propensity-matched survival analysis revealed decreased overall survival for patients who received adjuvant targeted therapy. A subgroup analysis of patients with pathologically positive lymph nodes also revealed decreased overall survival for patients who received adjuvant targeted therapy.

Despite applying rigorous statistical methodology to create equal groups for comparison, the survival analysis should be interpreted with caution due to the inherent risk of selection bias from unmeasured confounders.

A finding not immediately apparent is the multivariable analysis that patients with younger age, white race, and private insurance were more likely to receive adjuvant targeted therapy than other demographic groups. This is a good example of the socioeconomically privileged receiving more medical care, but without any improvement in outcomes. In fact, our data suggests that their outcomes may have been worse than if they did not receive adjuvant therapy.

Studies such as this one also highlight the fact that survival outcomes in randomized controlled trials are really a surrogate measure for survival in real-world clinical practice. Patients enrolled in clinical trials are significantly younger and healthier than those encountered in the real world. Especially in the case of poorly tolerated systemic therapy, clinicians should not expect to achieve the same outcome in their practice that has been demonstrated in trials. Poorly tolerated therapies with trial results revealing marginal effect-size but statistically significant outcomes should be heavily scrutinized before implementation into real-world clinical practice.

Written by: Nicholas H. Chakiryan, MD, Department of Urology, Oregon Health & Science University, Portland, Oregon

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