Pre-operative Prediction of Invasiveness in Renal Cell Carcinoma: The Role of Conventional Ultrasound and Contrast-Enhanced Ultrasound

Objective: It is known that in patients with renal cell carcinoma (RCC), the invasiveness of the tumor is closely related to the treatment and prognosis. Currently, histologic diagnosis of RCC is typically established after surgical removal of tumors or after biopsy. The use of non-invasive imaging modalities to predict the invasiveness of RCC is of great clinical value, particularly before surgery. In this study, the differences in conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) features between invasive and non-invasive RCC were analyzed with the aim of providing more accurate and valuable information for diagnosis and treatment to clinically opti-mize the treatment plan in a non-invasive manner and improve the prognosis of patients. Methods: Conventional US and CEUS features of 163 patients (total of 164 RCCs), obtained from the Lanzhou University Second Hospital in the period ranging from March 2021 to September 2022, were retrospectively analyzed. Patients were categorized into two groups: invasive group (n = 44) and non-invasive group (n = 120), with surgical pathology as reference standard. Receiver operating characteristic curves were drawn to evaluate the feasibility of differentiation. Results: The possibility of an intrarenal lesion/kidney ratio >50% in the invasive group (13/44, 29.5%) was signif-icantly higher than that in the non-invasive group (8/120, 6.7%) (p < 0.001). The absence of perilesional rim-like enhancement was more likely to imply invasive RCC (30/44, 68.2%) than non-invasive RCC (100/120, 83.3%) (p = 0.049) and was an independent predictor of invasive RCC. As for CEUS quantitative features, there were statistically significant differences in peak intensity (p = 0.009) or peak enhancement (p = 0.010), taking the largest range of lesion as the region of interest. Conclusion: Conventional US and CEUS features may help in the differentiation of invasive RCC from non-invasive RCC and have potential application value in the pre-operative prediction of RCC invasiveness.