Size and Volumetric Growth Kinetics of Renal Masses in Patients With Renal Cell Carcinoma

Objective To examine radiological growth patterns as an indicator of renal tumor aggressiveness, we studied about the growth kinetics of small renal mass (SRM, ≤4 cm) and possible associated factors for high Fuhrman nuclear grade (≥3). Materials and Methods From January 1999 to May 2013, 112 cases (111 patients) diagnosed as renal cell carcinoma after surgical treatment were reviewed retrospectively. Patients who had at least two preoperative contrast-enhanced computed tomography scans more than 6 months apart were included. Results The mean age was 59 years and mean computed tomography follow-up duration was 20 months. Median tumor size and tumor volume at diagnosis were 1.45 cm and 1.80 cm³, respectively. Median linear growth rate (LGR) was 0.28 cm/year. Median volumetric growth rate was 0.75 cm³/year and median volume doubling time was 1.41 years. Tumor growth rate was not different to histologic type (P = .271). High LGR was a significant factor associated with high Fuhrman grade in multivariate analysis (odds ratio 3.877, 95% confidence interval 1.715-8.765). Volumetric growth rate (P < .001) and volume doubling time (P = .004) were positive correlation with initial mass size, but not LGR (P = .764). Conclusion In our growth kinetics study, generally small renal mass grew slowly. High LGR could be a risk factor for high-grade tumor (Fuhrman grade ≥3).