Absence of Significant Correlation of Adverse Events Between First- and Second-Line Tyrosine Kinase Inhibitors in Patients With Metastatic Renal Cell Carcinoma

Several adverse events (AEs) commonly observed during treatment with different tyrosine kinase inhibitors (TKIs). The objective of the present study was to investigate whether the appearance of such AEs during treatment with first-line TKIs significantly affects the occurrence of AEs during second-line TKI therapy for patients with metastatic renal cell carcinoma (mRCC). The present study included 154 consecutive patients with mRCC treated with second-line TKIs after the discontinuation of first-line TKIs. The association of AEs, including diarrhea, fatigue, hand-foot syndrome, hypertension, and hypothyroidism, between first- and second-line therapies was analyzed in these 154 patients. For all 5 AEs assessed in the present study, the proportion of patients experiencing AEs or those grade ≥ 3 during second-line TKI therapy was not significantly different among the following 3 groups: patients without AEs, those with grade ≤ 2 AEs, and those with grade ≥ 3 AEs during first-line TKI therapy. Furthermore, no significant difference was seen in progression-free or overall survival after the introduction of second-line TKIs between patients with and without grade ≥ 3 AEs during treatment with first-line TKIs. The incidence of AEs or grade ≥ 3 AEs during second-line TKI therapy are not dependent on the profiles of AEs during first-line TKI therapy in patients with mRCC. Therefore, AEs that occur during first-line TKI therapy should not affect the selection of second-line targeted agents for patients with mRCC.