Prognostic value of the ratio of maximum to minimum diameter of primary tumor in metastatic clear cell renal cell carcinoma

BACKGROUND: Several models and markers were developed and found to predict outcome of advanced renal cell carcinoma. This study aimed to evaluate the prognostic value of the ratio of maximum to minimum tumor diameter (ROD) in metastatic clear cell renal cell carcinoma (mccRCC). METHODS: Patients with mccRCC (n = 213) treated with sunitinib from January 2008 to December 2018 were identified. Cutoff value for ROD was determined using receiver operating characteristic. Patients with different ROD scores were grouped and evaluated. Survival outcomes were estimated by Kaplan–Meier method. RESULTS: The optimal ROD cutoff value of 1.34 was determined for progression free survival (PFS) and overall survival (OS). Patients in ROD ≥ 1.34 group had shorter PFS (9.6 versus 17.7 months, p < 0.001) and OS (25.5 versus 32.6 months, p < 0.001) than patients in ROD < 1.34 group. After adjustment for other factors, multivariate analysis showed ROD ≥ 1.34 was an independent prognostic factor for PFS (p < 0.001) and OS (p = 0.006). Patients in ROD ≥ 1.34 group presented higher proportions of pT3/4 stage (89.2% versus 10.8%, p = 0.021), WHO/ISUP grade III/IV (72.0% versus 28.0%, p = 0.010), tumor necrosis (71.0% versus 29.0%, p = 0.039), sarcomatoid differentiation (79.1% versus 20.9%, p = 0.007), poor MSKCC risk score (78.4% versus 21.6%, p < 0.001) and poor IMDC risk score (74.4% versus 25.6%, p < 0.001) than ROD < 1.34 group. CONCLUSION: Primary tumor with higher ROD was an independently prognostic factor for both PFS and OS in patients with mccRCC who received targeted therapy. Higher ROD was also associated with high pT stage, high WHO/ISUP grade, sarcomatoid features, tumor necrosis, poor MSKCC and IMDC risk score. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12894-022-01047-y.