Observations on the growth rate of renal cell carcinoma.

We retrospectively reviewed the records of 18 patients to investigate the growth rate of renal cell carcinoma (RCC). Growth rates were calculated from two or more gross measurements of neoplastic foci in the kidney (6 cases) and lung (12 cases). RCCs in primary sites grew slowly and the tumor volume doubling time (DT) raged from 372 to 579 days (468 +/- 84.6). Pulmonary metastases present in 12 cases grew rapidly, with a DT ranging from 20 to 154 days (89.4 +/- 43.0). Tumors in both the kidney and lung were composed of cancer cells with equal proliferative activity, as determined by immunohistochemical analysis of argyrophilic nucleolar organizer regions and proliferating cell nuclear antigen activity. Thus, our results suggest that, in addition to the proliferative activity of cancer cells, the microenvironment of the specific region is an important determinant of the growth rate of cancer cells.