Imaging modality, incidental detection, and age–stage distribution in surgically treated clear cell renal cell carcinoma

OBJECTIVES: To compare ultrasonography (US) and computed tomography (CT) in detecting clear cell renal cell carcinoma (ccRCC) according to tumor stage and mode of presentation. METHODS: We conducted a monocentric cross-sectional study of patients undergoing surgery for renal tumors between 2011 and 2020. Patients were classified by detection mode, imaging modality, histological subtype, and tumor stage. Logistic and linear regression models were used to assess associations adjusted for relevant covariates. RESULTS: Among 804 eligible patients, 576 had ccRCC, of whom 83.3% were detected incidentally. US and CT were used in 52.1% and 47.9% of cases, respectively. Overall detection rates did not differ significantly between modalities (OR 1.08; p = 0.381). However, US was more likely to detect incidental ccRCC at stages I-II (OR 1.26; 95% CI: 1.05-1.52; p = 0.012). Incidental ccRCC was more likely to be detected by US than symptomatic ccRCC (adjusted OR 2.32; p = 0.001). Mean age at diagnosis increased with tumor stage, with an adjusted age-stage gradient of 3.03 years between stage III-IV and stage I-II ccRCC (p = 0.002). CONCLUSIONS: US was associated with incidental early-stage ccRCC detection. The observed age-stage gradient provides hypothesis-generating evidence compatible with time-dependent ccRCC progression.