Impact of multikinase inhibitor approval on survival and physician practice patterns in advanced or metastatic medullary thyroid carcinoma.

ABSTRACT

BACKGROUND: This study aimed to identify whether multikinase inhibitor approval for medullary thyroid carcinoma was associated with changes in systemic therapy administration or overall survival. METHODS: The National Cancer Database was queried for advanced medullary thyroid carcinoma patients. Clinicopathologic comparisons were performed between premultikinase inhibitor (2005-2010) and postmultikinase inhibitor (2011-2016) approval groups. Multivariable logistic and Cox regressions were applied to assess predictors of systemic therapy and overall survival. RESULTS: A total of 2,891 patients met the criteria. Postmultikinase inhibitor patients were less likely to undergo radiation (P = .02) and more likely to receive systemic therapy (P = .01). The rate of systemic therapy nearly doubled from 2010 to 2011 (8.1% to 13.8%, P = .04); it subsequently declined back toward preapproval rates. Before multikinase inhibitor approval, only metastases and radiation were associated with systemic therapy (P < .05). After multikinase inhibitor approval, patients with small tumors, extrathyroidal extension, positive lymph nodes, or metastases were more likely to receive systemic therapy (P < .05). The 5-year overall survival between pre and postmultikinase inhibitor groups, for those who received systemic therapy (n = 288), was similar (P = .58), even when restricted to patients with distant metastases (P = .55). CONCLUSION: After approval of multikinase inhibitors, physicians broadened the criteria for systemic therapy. Prescription rates have since declined. Given the toxicities of these drugs and no improvement in overall survival since introduction, selective utilization may be warranted.