Urinalysis by combination of the dipstick test and urine protein–creatinine ratio (UPCR) assessment can prevent unnecessary lenvatinib interruption in patients with thyroid cancer

Abstract

Background Proteinuria induced by lenvatinib is a class effect that occurs secondary to VEGFR suppression. Withholding of lenvatinib is required in cases with severe proteinuria. Urine protein–creatinine ratio (UPCR, g/gCre) has recently attracted attention as an alternative to 24-h urine collection for assessing proteinuria. The aim of this study was to examine the correlation between the results of proteinuria assessed by the dipstick test and UPCR, and to investigate the influence of proteinuria grading with UPCR on lenvatinib dose adjustment compared to that with only the dipstick test. Method Three hundred and ten urine samples from 63 patients with advanced thyroid cancer under treatment with lenvatinib, which were tested by both the dipstick test and UPCR were analyzed. Lenvatinib was withheld when there was evidence of CTCAE grade 3 proteinuria, and restarted when it resolved. The frequency of proteinuria, correlation between the results of the dipstick test and UPCR test, and the effect of dose withholding in cases with results of 3 + in the dipstick test were calculated. Results Proteinuria was seen in 56 (88.9%) patients. Of the 154 dipstick 3 + samples, only 56 (36.4%) were judged as more than 3.5 g/gCre by UPCR (grade 3 proteinuria), although none of the 1 + and only 3.7% of 2 + samples were judged as grade 3 proteinuria. We were able to prevent unnecessary lenvatinib interruption due to proteinuria in 63.6% of dipstick 3 + samples by assessment of UPCR. Conclusions Urinalysis by combination of the dipstick test and UPCR assessment might be a better strategy for preventing unnecessary interruption of lenvatinib.