Tumor shrinkage patterns of nivolumab monotherapy in metastatic renal cell carcinoma.

Objectives: To investigate the tumor shrinkage patterns of patients with metastatic renal cell carcinoma treated with nivolumab monotherapy. Methods: Forty‐four consecutive patients with metastatic renal cell carcinoma treated with nivolumab monotherapy (81 metastatic and four primary lesions) between September 2013 and December 2020 were retrospectively analyzed. The tumor shrinkage rate of individual visceral and lymph node metastatic lesions and the primary site lesions treated with nivolumab monotherapy, as well as the association between overall survival and pretreatment tumor size, were statistically assessed. Results: Pretreatment tumor size for the total and individual target lesions, which included kidneys, lungs, pancreas, and lymph nodes, were not correlated with tumor shrinkage rate. The tumor shrinkage rate was found to have no significant association with pretreatment tumor size between any organ. In addition, there is no significant difference in tumor shrinkage rate between larger (>median value) and smaller (<median value) pretreatment tumor size in any organ. Finally, there was no significant difference in overall survival between larger and smaller pretreatment tumor size. Conclusions: Pretreatment tumor size was not associated with the tumor shrinkage rate and overall survival in nivolumab monotherapy. [ABSTRACT FROM AUTHOR]