Study: Metastases occur even in small kidney tumors

Small kidney tumors have an aggressive potential and should be treated, according to the results of a large multicenter study presented at the European Association of Urology annual congress in Milan, Italy.

"Many clinicians regard small renal cell cancer as having a benign biologic behavior, and non-operative surveillance protocols are often being used in patients with small renal tumors," wrote the authors, led by Sandra Steffens, MD, of Hannover Medical School, Hannover, Germany. "The aim of this large retrospective multicenter study was to evaluate the prevalence of locally advanced growth and distant metastases in patients with small renal cell carcinomas following surgery."

The study included 2,197 patients with renal tumors 4 cm or smaller in maximal tumor diameter and complete patient and tumor-specific characteristics from six centers in Germany between 1990 and 2011.

The risk of presenting nodal disease or distant metastasis increased insignificantly with rising tumor diameter. After a mean follow-up of more than 5 years, the tumor-associated death rates were 6.5%, 7.6%, and 8.4% in the ≤2 cm, 2 cm-3 cm, and 3 cm-4 cm tumor diameter subgroups, respectively. Kaplan-Meier 5-year cancer-specific survival rates did not differ significantly: 93.3%, 92.1%, and 92.8%.

Patients with no lymphatic or distant metastasis at the time of diagnosis or surgery had a 5-year cancer-specific death rate of 5.8%. Five-year cancer-related death rate was significantly higher among the 75 patients with nodal or distant involvement at the time of surgery (p<.001).

In conclusion, the authors stress that lymph node and distant metastases occur even in small kidney tumors.

Look for more coverage of the European Association of Urology annual congress in an upcoming issue of Urology Times.

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