Italian Registry on Rare Urological Tumors (Meet-URO-23): The First Analysis on Collecting Duct Carcinoma of the Kidney.

• The Meet-URO 23/I-RARE study is a retrospective and prospective study on rare genitourinary cancer. • We enrolled 37 patients with collecting duct carcinoma (CDC), male:female ratio: 3:1. • Seven patients were metastatic at diagnosis. 33 patients received first-line therapy, 4 only nephrectomy. • We confirmed the dismal prognosis of CDC, with a median overall survival (OS) of 22.1 months. • The median relapse-free survival was 3.7 months, while median progression-free survival (PFS) was 3.3 months. • PFS appeared to be longer in female and in patients with a good performance status (PS). • A better OS was reported in female patients and in patients with a good PS. Rare genitourinary tumors are lacking of randomized and observational data. We aimed to describe the clinical characteristics and outcomes of patients with collecting duct carcinoma (CDC) through the Meet-URO 23/I-RARE database. We performed a multicentric retrospective-prospective study within the Meet-URO network, enrolling patients from March 2021 (retrospectively up from 2011) until March 2023. The primary objective was to describe the clinical characteristics of patients with CDC, the secondary objectives were to assess the oncological outcomes in terms of relapse-free survival (RFS), progression-free survival (PFS), overall survival (OS) and objective response rate (ORR) to treatment. 37 patients with CDC were enrolled. Four patients underwent only surgery, 33 received first-line systemic therapy. Median OS was 22.1 months (95% CI, 8.9-31.9). Median RFS for patients with localized disease at onset (n = 30) was 3.7 months (95% CI, 1.9-12.8), median PFS for first-line treatment was 3.3 months (95% CI, 2.7-9.9), with an ORR of 27%. Female sex and good performance status (PS) were associated with longer PFS (P =.072 and P <.01, respectively) and OS (P =.030 and P =.141, respectively). Patients with CDC had dismal prognosis, with scarce benefit from the available treatments. Female sex and good PS seemed to be associated with better prognosis. The Meet-URO 23/I-RARE is a retrospective-prospective study on rare genitourinary cancer. This analysis described the characteristics and outcomes of 37 patients with collecting duct carcinoma. Median overall survival (OS) was 22.1 months and median progression-free survival (PFS) for first-line treatment was 3.3 months. Female sex and good performance status seemed associated to longer OS (p =.030) and PFS (p <.01), respectively. [ABSTRACT FROM AUTHOR]