Prognostic evaluation based on radiological morphological characteristic for tumors larger than 7 cm in renal cell carcinoma

Purpose To predict survival prognosis of renal cell carcinoma (RCC) patients with tumors larger than 7 cm by preoperative radiological morphological features. Methods We reviewed the medical records of RCC patients with tumors larger than 7 cm from 2007 to 2017 in Zhongshan Hospital, Fudan University. A total of 251 patients’ clinical data were collected. 25 and 9 patients were excluded due to loss of follow-up and lack of imaging data, respectively. PFS and OS from date of surgery were evaluated. We defined the irregularity of the tumor as the morphological feature studied and quantified it according to a theorem of the ellipse: the length from the midpoint of the ellipse to any point on the ellipse is shorter than or equal to 1/2 of the long axis. The cutoff value of irregularity was calculated based on the ROC curve. Cox proportional hazards regression models were used to test associations between features and outcome. Results Of all the 217 patients included in the study, 67 patients had disease progression and 30 patients died. The cutoff value of the irregularity was selected to be 0.5335. Adrenal invasion, presence of distant metastasis and irregularity of tumors were significantly associated with PFS, and presence of distant metastasis and irregularity of tumors were significantly associated with OS. Conclusions For patients with tumors larger than 7 cm in RCC, we found a radiological index that is closely related to the prognosis: irregularity. This is an unreported independent prognostic risk factor that can be quantified before surgery.