Introduction

Overtreatment of older patients with a small renal mass is a relevant concern and active surveillance [AS] represents an attractive management. However, current criteria for AS eligibility lack of validation. The aim of the study was to validate a criterion for AS eligibility based on tumour clinical size and age on a cohort of patients treated with surgery.

Methods

1922 patients diagnosed with a cT1cN0cM0 renal mass elected for surgical treatment and collected into a prospective database were assessed. Under the assumption that older patients with smaller tumours are optimal candidates for AS relative to younger patients with larger tumours, we relied on the ratio [R] between tumour clinical size and age in order to differentiate patients suitable for AS (R<5) from patients unsuitable for AS (R≥5). X2 test was used to compare the rate of malignant histology, stage pT3-pT4 and grade G3-G4 at final pathology in patients suitable vs. unsuitable for AS. Smoothed Poisson?s incidence plots were used to examine the rate of cancer specific [CSM] and other cause mortality [OCM] in patients suitable vs. unsuitable for AS.

Results

According to the proposed definition, the rate of patients suitable for AS was 34%. Patient suitable for AS had a lower rate of malignant histology (78 vs. 87%; p<0.001), pT3-pT4 (4 vs. 10% p=0.001) and grade G3-G4 (7 vs. 17% p<0.001) relative to patients unsuitable for AS. In patients suitable for AS, the 10-year rates of CSM and OCM were 1.7 and 19%, respectively (Fig. 1A). In patients unsuitable for AS, the 10-year rates of CSM and OCM were 6.7 and 11% (Fig. 1B), respectively.

Conclusions

When validated in a cohort of surgically treated patients, the ratio between tumour clinical size and age is a useful parameter to differentiate patients with adverse pathologic outcomes from patients with more favourable pathologic outcomes. These differences translate into critically different relative rates of CSM and OCM. These findings suggest that the proposed strategy criterion deserve further examination as a potential criterion for AS.

Funding

None