Factors associated with postoperative renal sinus invasion and perinephric fat invasion in renal cell cancer: treatment planning implications

In patients with renal cell carcinoma (RCC), postoperative upstaging including perinephric fat invasion (PNI) and renal sinus invasion (RSI) leads to unfavorable oncological outcomes. Determining the preoperative risk factors for postoperative upstaging could be beneficial for treatment planning. In this study, 267 RCC patients who underwent radical nephrectomy were studied retrospectively. The RSI incidence was significantly greater than that of PNI. Kaplan-Meier analysis revealed that patients with RSI, PNI, and RSI plus PNI had poorer disease-free-survival than those with neither RSI nor PNI. Univariate and multivariate logistic regression analyses indicated that a tumor extension into the sinus, an irregular tumor-sinus border, and an irregular tumor shape in CT/MRI imaging were independent risk factors for RSI. And a tumor larger than 5 cm, an irregular tumor-perinephric fat border, and a tumor necrosis were independent risk factors for PNI. Subgrouping of patients into low-, moderate-, and high-risk groups according to these factors, revealed a direct association between the risk factors and PNI/RSI incidence. In conclusion, in patients with RCC, preoperative risk factors associated with postoperative upstaging could be assessed by imaging data obtained using CT or MRI. Preoperative Risk group classification would be clinically useful for patient counseling and treatment planning.