Metastasis-directed treatment (MDT) for patients (pts) with non-clear cell renal cell carcinoma (nccRCC): Results from a matched 15-year retrospective cohort.

497 Background: nccRCC represents a diverse group of diseases with variable clinicopathological features. We aimed to evaluate the impact of MDT on clinical outcomes of pts with nccRCC. Methods: We reviewed our institutional database (São Paulo State Cancer Institute, University of São Paulo) to identify pts with ICD-C64 (kidney cancer) with nccRCC. Electronic medical records were reviewed to register the clinical and pathological features. Histological subtypes were classified as per the 2022 World Health Organization classification. MDT was considered as any focal treatment (surgery or radiation) given with non-palliative intent. Overall survival (OS) was calculated as the time from diagnosis of metastatic disease until death or last follow-up. Survival probabilities were estimated using the Kaplan-Meier method and compared via the log-rank test. To correct for imbalances between MDT recipients and non-recipients, we applied a propensity score matching based on the International Metastatic RCC Database Consortium (IMDC) classification, ECOG-PS, subtype, number of affected organs, and presence of sarcomatoid features in the primary tumor. Results: From September 2009 to January 2024, we identified 2,867 pts with kidney cancer. From 620 pts diagnosed with nccRCC, 143 (23.1%) had metastatic disease. Of these, MDT was administered to 39 pts. Clinicopathological features of pts treated with MDT vs. non-treated with MDT were described in the table. Most common MDT was surgery (n=30), followed by radiosurgery (n=9). MDT was associated with improved OS (HR 0.24, 95% CI 0.14-0.40, median 8.0 vs. 58.6 months), confirmed after propensity score matching (HR 0.31, 95% CI 0.17-0.56, median 17.5 vs. 58.6 months). In the matched cohorts, MDT was associated with increased OS in chromophobe (HR 0.33; 95% CI 0.08-1.29, median 23.3 vs. 69.3 months), papillary (HR 0.29; 95% CI 0.12-0.70, median 16.7 vs. 47.7 months), and unclassified subtypes (HR 0.16; 95% CI 0.04-0.66, median 3.1 vs. 18.9 months). Conclusions: This retrospective analysis suggests that a subset of pts with nccRCC may benefit from MDT, regardless of histological subtype. Clinicopathological features of pts treated with MDT vs. non-treated with MDT. Variable Overall Population (%) MDT (%) Non-MDT (%) Age (median) 57 53.8 57.3 T StageT1- T2T3-T4 25 (17)90 (62) 11 (28)22 (56) 14 (13)68 (64) IMDCFavorableIntermediatePoor 29 (20)64 (44)49 (34) 13 (33)19 (49)6 (15) 16 (15)45 (42)43 (40) ECOG0 – 1≥2 93 (64)42 (29) 32 (82)4 (10) 61 (57)38 (36) SubtypePapillary Chromophobe Collecting DuctAngiomyolipoma MIT Translocation Unclassified Others Medullary carcinoma 72 (49) 20 (13) 4 (3) 1 (1) 12 (8) 25 (17) 7 (5) 5 (3) 19 (48)9 (23)001 (3)8 (21)2 (5)0 53 (50)11 (10)4 (4)1 (1)11 (10)17 (16)5 (5)5 (5) MetastasisLungLiverCNSBone 59 (40)15 (10) 48 (33) 76 (52) 14 (36)13 (33)6 (15)13 (33) 62 (58)35 (33)9 (8)46 (43)