Introduction: Much has been written about the prognosis of Renal Cell Carcinoma (RCC) patients upstaged from cT1a to pT3a. However, the nature of the pT3a stage is diverse according to the current TNM (Tumor Node Metastasis) including perinephric fat invasion (PFI), renal sinus fat invasion (SFI), and renal vein branch extension (RVBE) and the prognosis of <4 cm tumors staged T3a due to the intraoperative finding of thrombus has never been explored. We aim to analyze the descriptive data in patients after Partial Nephrectomy (PN) with stage cT1a renal cell carcinoma (RCC) who were upstaged to stage T3a due to intraoperative finding of thrombus in the renal vein branches. Methods: A retrospective descriptive analysis of our single center kidney cancer database was performed, which identified T1a RCC patients upstaged to T3a due to thrombotic intraoperative finding after PN between 2013 and 2022. Categorical variables were presented using frequency and percentage. Continuous variables presented with median and inter-quartile range. Results: A total of 20 patients were included. Median age was 63.1 ± 11.8. 11 (55%) were male, and 9 (45%) were female. The mean BMI was 28.2±4.1 and median Charlson Comorbidity Index was 4 (IQR: 3, 5). The median renal score was 7, the mean tumor size was 3.2±1.1 and 70% of tumors were left lateral tumors. Median operative time was 120 minutes (IQR 111, 138), and ischemia time was 10 minutes (IQR 11, 13). EBL was 50ml (IQR 50, 75) and length of stay was 1 day (IQR 1,1). Two (10%) patients had post-operative complications. Most common tumor histology was clear cell RCC(60%), and no patients had positive surgical margins. At the median follow-up of 11.4 (3.7, 36.2) months, no patient had experienced recurrence. Conclusions: No studies have described the recurrence characteristics of pT3a RCC with RVB. The treatment outcomes of patients with cT1a RCC upstaged to pT3a after PN remains controversial. Comparative studies are needed to provide conclusions on recurrence data and guidance in terms of follow-up and further treatment for these patients. SOURCE OF Funding: none
