The role of percutaneous needle biopsy in differentiation of renal tumors.

OBJECTIVE

The safety and accuracy of active percutaneous needle biopsy for small renal tumors have been reported. However, there have been few reports of passive biopsy for renal tumors without clear pretreatment histological characterization based on imaging studies due to the rarity of these tumors. In this study, we examined the background, accuracy, adverse events and patient prognosis associated with such biopsies.

METHODS

Japanese patients with renal tumors histological characteristics of which were unclear on imaging prior to treatment were enrolled in this study and analyzed retrospectively. The study population consisted of 24 renal cell carcinoma patients and 13 non-renal cell carcinoma patients.

RESULTS

Although the percentage of hypervascularity was significantly higher in clear cell renal cell carcinoma compared with the other neoplasms (P < 0.001), there were no significant differences between renal cell carcinoma and non-renal cell carcinoma with regard to hypervascularity, hydronephrosis, venous thrombus, hematuria or metastasis. The histological results in eight of nine (89%) nephrectomy patients were in accordance with those of biopsies. The median survival time of all 37 patients was 21 months and the 5-year survival rate was 31.1%. The 5-year survival rates of nephrectomy patients and non-nephrectomy patients were 75 and 0%, respectively. The overall survival of nephrectomy patients was significantly better than that of non-nephrectomy patients (P = 0.003).

CONCLUSIONS

Biopsy of renal tumors is safe and accurate regardless of the type of guidance and nephrectomy after appropriate diagnosis by biopsy contributed to longer survival.