The effect of preoperative glycemic control measured by HbA1c on renal cell carcinoma (RCC) outcome remains controversial. Thus, the investigators aim to examine the association of preoperative glycemic control with oncologic outcomes after radical or partial nephrectomy. The investigators will prospectively collect the relevant data including preoperative HbA1c in 238 patients of RCC patients undergoing nephrectomy. The associations between clinical variables and risk of adverse pathological features and disease recurrence will be tested using a multivariate logistic regression and multiple Cox-proportional hazards model, respectively.

• This is the observational study as the single institutional, prospective cohort study. The investigators prospectively collect the clinicopathological information of the patients with renal cell carcinoma (RCC) undergoing partial or radical nephrectomy.
• Particularly, the investigators check the variables, including age at surgery, body mass index, sex, comorbidities, preoperative HbA1c levels, blood urea nitrogen (BUN)/creatinine levels, estimated-GFR, clinical TMN staging by CT scan, final pathological results (TMN stage, histology, and Fuhrman nuclear grade), warm ischemic time and surgical margin status (in the case of partial nephrectomy), postoperative recurrence and distant metastasis, renal function changes during follow-up periods.
• The study protocol is same with routine follow-up schedule of the patients with RCC treated with nephrectomy. Typically, the investigators check the patients at 1, 3, 6, 12, 18, 24, 30 and 36 months. However, according to the patients status and preference, follow-up schedule can be changed within 3 months at specific time points. Because the present study is the observational cohort study, not intervention study, subtle changes of follow-up schedule would not affect on the primary outcomes.
• Importantly, preoperative HbA1c should be checked within 1 month before operation, same as the routine preoperative laboratory tests.

Inclusion Criteria:

• Renal cell carcinoma (RCC) by image work-up such as CT scan
• Clinically localized RCC
• Aged over 20 years
• Patients undergoing radical or partial nephrectomy

Exclusion Criteria:

• distant metastasis, preoperatively
• preoperative targeted therapy
• preoperative immunotherapy
• medications affecting glucose status other than diabetes mellitus

Enrolled patients should be diagnosed with renal cell carcinoma by ultrasonography and/or CT scan, MRI. In addition, the participants should be treated with radical or partial nephrectomy.