Abstract Code: IUC25516-84
Non clear renal cell carcinoma: metastatic patterns and survival from a real‑world cohort
- Maamoun 1, M. Al-Essa 2, I. Pedley 3, A. Azzabi 3, S. Grumett 2, M. Elgendy 3
(1) Newcastle hospitals – United Kingdom, (2) Queen Elizabeth Hospital – University Hospitals Birmingham NHS Foundation Trust – United Kingdom, (3) Newcastle Hospitals – United Kingdom
Background:
Non clear cell RCC (nccRCC) is heterogeneous and under represented in trials. We describe demographics, metastatic patterns—highlighting brain involvement in MIT‑family disease—and overall outcomes.
Methods:
Retrospective cohort across two large UK centres (2012–2025). PFS was calculated from first‑line therapy to radiological progression/death; OS from metastatic diagnosis to death/last follow‑up. Kaplan–Meier medians with 95% CIs were estimated overall and by histology.
Results:
Forty one patients were included (median age 56; 56% male); IMDC: favourable 22%, intermediate 61%, poor 17%. Histologies: papillary 23/41, chromophobe 6/41, unclassified 6/41, MIT‑family/TFE3 5/41, oncocytic 1/41. Nodal disease was most frequent overall (30/41). Three patients had brain metastases, of whom two were MIT‑family, aligning with this subtype’s observed metastatic pattern. Second site patterns varied: lung in papillary/unclassified, liver in chromophobe, brain in MIT‑family, and bone in oncocytic variants. KM estimates for the overall cohort: mOS 24.15 months (95% CI 24.38–49.41); mPFS 13.93 months (95% CI 16.10–49.41). By histology, papillary mOS/mPFS: 24.38 (NR–24.38)/16.10 (17.25–NR); chromophobe: 24.15 (6.64–49.41)/24.15 (5.68–49.41); unclassified: 11.01 (6.70–18.79)/7.52 (2.46–NR); MIT‑family: 47.54 (NR–NR)/7.52 (5.32–NR). Small subgroup sizes account for wide CIs.
Conclusion:
Metastatic patterns differed by histology; brain metastasis was relatively common and observed in 40% of MIT family tumours, supporting consideration of baseline contrast‑enhanced head CT/MRI in this subgroup. Survival also varied by subtype, with unclassified tumours showing the poorest outcomes and MIT family displaying the longest OS despite limited events. These real‑world findings support subtype informed imaging strategies but require validation in larger, multi‑centre cohorts.