Small kidney tumours have an agressive potential and should be treated, according to a the results of a large multicentre study presented at the 28th Annual EAU Congress in Milan.

“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 tumours,” write the authors in the findings.

“The aim of this large retrospective multi-centre study was to evaluate the prevalence of locally advanced growth and distant metastases in patients with small renal cell carcinomas following surgery."

The investigation included 2197 patients with RCC of 4 cm or smaller in maximal tumour diameter and complete patient and tumour specific characteristics from six centers in Germany between 1990 and 2011.

The risk of presenting nodal disease or distant metastasis increased insignificantly with rising tumour diameter. After a mean follow-up of more than 5 years, the tumour-associated death rates were 6.5, 7.6, and 8.4 % in the ≤ 2 cm, 2-3 cm, and 3-4 cm tumour diameter subgroups, respectively. Kaplan-Meier 5-year cancer specific survival (CSS) 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 %. 5-year cancer related death rate was significantly higher among the 75 patients with nodal or distant involvement at the time of surgery (p<0.001).

In conclusion, the authors stress that lymph node and distant metastases occur even in small RCCs: “These results have significant implications since the rate of patients diagnosed with small renal masses is increasing and non-operative surveillance protocols are currently being used in patients with small renal tumour."

Source: EAU