For metastatic renal cell carcinoma patients with fewer adverse risk factors and fewer metastatic disease sites, initial active surveillance may be a safe and feasible approach to delay the toxicities of systemic therapy, investigators report.

Fifty-two patients with treatment-naive, asymptomatic, metastatic renal-cell carcinoma were enrolled in a prospective phase II trial and radiographically assessed at baseline, every 3 months for year 1, every 4 months for year 2, then every 6 months thereafter. Patients continued on observation until the treating physician and patient made the decision to initiate systemic therapy.

Median follow-up time was 38.1 months and median time on surveillance before treatment initiation – the primary endpoint of the study – was 14.9 months (95% confidence interval, 10.6-25.0), reported Brian Rini, MD , of the Cleveland Clinic Taussig Cancer Institute and his associates (Lancet Oncol. 2016. doi: 10.1016/S1470-2045(16)30196-6 ).

Forty-three (90%) of the 48 evaluable patients experienced disease progression during the study, median time to progression was 9.4 months, and 22 patients died from renal cell carcinoma. One patient developed brain metastases and died without receiving systemic therapy. In multivariable analysis, only the number of involved organs (P = .0414) and number of International Metastatic Database Consortium risk factors (P = .0403) were independently prognostic.

Using this analysis, Dr. Rini and associates identified two prognostic groups – a favorable group consisting of patients with no or one International Metastatic Database Consortium (IMDC) risk factors and two or fewer organs with metastatic disease, and an unfavorable group consisting of all other patients. The favorable group (n = 22) patients had an estimated median surveillance time of 22.2 months (95% CI, 13.8-33.3), whereas the unfavorable group (n = 19) had an estimated median surveillance time of 8.4 months (3.2-14.1; P = .0056).

Anxiety, depression, and quality of life did not change significantly over the period of surveillance, suggesting that living with untreated cancer did not cause psychological harm to patients in this study.

“Findings from our prospective trial show active surveillance to be a viable initial strategy in some patients with metastatic renal-cell carcinoma. The median surveillance period before start of systematic therapy was greater than 1 year, with no observed adverse effects on quality of life, anxiety and depression,” Dr. Rini and his associates said.

“Appropriate selection of patients and adequate monitoring, which should include CNS surveillance, is crucial in application of this approach,” they added.

This study was unfunded. One investigator reported receiving financial compensation from Pfizer and GlaxoSmithKline. All other investigators reported having no relevant disclosures.

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