[A pathological comparison of primary and metastatic lesions as a prognostic indicator for renal cell carcinoma]

The purpose of this study is clarify the changes in histological grade between primary and metastatic lesions in renal cell carcinoma. A tota of 100 cases of renal cell carcinoma and their metastases were compared respectively. In 31 (31%) of the cases observed, metastatic lesions were observed to have higher grade of malignancy when compared to primary lesions. In 59 (59%) of the cases, metastatic lesions had the same grade of malignancy and in 10 (10%) of the cases, metastatic lesions had a lower grade of malignancy when compared to primary lesions. The frequency of upgrading cases in young patients (i.e. less than 40 years old) occurred with less frequency when compared to elderly patients. Additionally, the frequency of upgrading cases involving female patients was lower when compared to male patients. The one year survival rates in patients, who received nephrectomy, having grade 1 to 4 lesions following metastases were 100%, 65%, 71%, and 27% respectively. From these percentages, a statistically significant difference exists in one year survival rates between patients with grade 2 and 4 metastatic lesions (p < 0.005), and grade 3 and 4 metastatic lesions (p < 0.01). Histological grade of metastatic lesions is an important prognostic indicator for determining the outcome of renal cell carcinoma following metastases. Thus it is important that the prognosis of renal cell carcinoma be based on the histological grade of metastatic lesions as well as primary lesions.