An inadequate number of first-line chemotherapy cycles provides poor survival outcomes in patients with metastatic urothelial carcinoma receiving avelumab maintenance: results from the chu-shikoku Japan urological consortium.

Purpose: Despite 4-6 cycles of first-line chemotherapy being recommended before the initiation of avelumab maintenance treatment, a non-negligible number of patients received <4 cycles of first-line chemotherapy due to adverse events or pre-existing comorbidities. We assessed the prognostic impact of the number of first-line chemotherapy cycles in patients with metastatic urothelial carcinoma (mUC) treated with avelumab maintenance.

Methods: In this multi-institutional study, data were collected from patients with mUC who received avelumab maintenance treatment following first-line chemotherapy. Patients were divided into those who received <4 cycles versus ≥4 cycles of first-line chemotherapy. Kaplan-Meier curves and Cox regression analysis were used to assess the association of chemotherapy cycle numbers with overall survival (OS) and cancer-specific survival (CSS).

Results: Of 91 patients included in this analysis, 17 (19%) underwent <4 cycles of chemotherapy. Patients with <4 cycles of first-line chemotherapy were less likely to receive carboplatin-containing chemotherapy compared with their counterparts (6% versus 39%). On multivariable Cox regression analyses adjusted for the effects of confounding factors, receiving <4 cycles of chemotherapy was significantly associated with worse OS and CSS (HR 2.85; P = .006 and HR 3.18; P = .005, respectively), which was confirmed by subgroup analysis focusing on patients with 1-6 cycles of chemotherapy. Cisplatin-based chemotherapy use was associated with better OS over carboplatin-based chemotherapy (HR 0.41; P = .033).

Conclusions: An inadequate number of first-line chemotherapy cycles was associated with poor survival outcomes. Four or more cycles of first-line platinum-based chemotherapy may be beneficial to ensure the efficacy of avelumab maintenance treatment in patients with mUC.