Initial active surveillance for patients with metastatic renal cell carcinoma: 10 years' experience at a regional cancer Centre.

A subset of patients with metastatic renal cell carcinoma (mRCC) follow an indolent disease course and may benefit from initial active surveillance (AS). However, selecting patients suitable for this approach is challenging. To investigate this we sought to define outcomes of patients with mRCC suitable for initial AS. All patients with mRCC clinically selected for initial AS at the Edinburgh Cancer Centre between January 2010 and December 2020 were identified. Key inflammatory biomarkers (haemoglobin, white cell count, neutrophil count, platelets, C-reactive protein [CRP], albumin, corrected calcium) and the International Metastatic RCC Database Consortium (IMDC) risk score were measured. The relationship between these and time to systemic anticancer therapy (tSACT) and overall survival (OS) was analysed. Data were available for 160 patients. Estimated median overall survival was 88.0 (interquartile range [IQR] 34.0-127.0) months. Median tSACT was 31.8 (IQR 12.0-76.3) months. On multivariate analysis, only CRP was predictive of tSACT (HR 2.47 [95% CI:1.59-3.85] p < 0.001) and OS (HR 3.89 [95% CI:2.15-6.83] p < 0.001). Patients with CRP > 10 mg/L were more likely to commence SACT within 1 year than those with CRP≤10 mg/L (41% vs. 18%, Relative Risk 2.16 (95% CI:1.18-3.96) (p = 0.012)). IMDC risk score was not predictive of tSACT or OS. Active surveillance is an appropriate initial management option for selected patients with mRCC. CRP, a biomarker of systemic inflammation, may provide additional objective information to assist clinical decision-making in patients with mRCC being considered for initial AS. Although this is a retrospective observational study, the cohort is well defined and includes all patients managed with initial AS in an inclusive real-world setting.