Role of collateral vessels on contrast-enhanced computed tomography in predicting metastatic potential for small renal cell carcinoma

Abstract

Abstract Background The presence of collateral vessels (CVs) on contrast-enhanced computed tomography is a poor prognostic factor in renal cell carcinoma (RCC), but its value in small RCC (sRCC; < 4 cm) remains unknown. In this study, we investigated whether presence of CVs is a predictor of high potential for metastasis in sRCC. Methods We retrospectively reviewed clinical and imaging data of patients with pathologically confirmed sRCC evaluated at our institution between 2011 and 2021. All sRCCs were pathologically diagnosed by biopsy, metastasectomy, partial nephrectomy, or radical nephrectomy. CVs were defined as blood vessels of any diameter connecting the tumor with the surrounding perirenal tissues on contrast-enhanced computed tomography. The rate of metastasis-free survival (MFS), defined as the time from pathological diagnosis to confirmed metastasis, was compared among patients without CVs, those with one CV, and those with two or more CVs. Results Of 141 patients, 4 (2.8%) had metastatic sRCC at initial diagnosis. In the 137 patients with nonmetastatic sRCC, the diagnosis was pathologically confirmed following radical surgery. The median follow-up period from pathological diagnosis was 73.9 months, and the overall 5-year MFS was 93.5%. The 5-year MFS was significantly poorer in patients with two or more CVs than in those with one CV (63.8% vs. 96.3%; p = 0.0003) and those without CVs (63.8% vs. 100%; p < 0.0001). Conclusions sRCCs with two or more CVs might have high potential for metastasis. Conversely, sRCCs without CVs might not be aggressive and be suitable for active surveillance.