Is observation a valid strategy in metastatic renal cell carcinoma?

Metastatic renal cell carcinoma (mRCC) is a diagnosis with wide variation in outcome; prognostic categories of favourable, intermediate and poor risk based on clinical criteria are widely used in routine clinical practice. The observation that a subgroup of patients has indolent disease associated with prolonged survival was recognized before the introduction of novel targeted agents. This led to interest in a strategy of deferring systemic therapy in selected patients. This review will consider data that have evaluated the safety and acceptability of such a strategy in the era of effective systemic therapies for mRCC.

Data from five retrospective studies, one prospective cohort and a subgroup of a randomized phase III trial lend support to the strategy of deferral of systemic therapy for carefully selected patients with mRCC. Prospectively collected data also indicate that this approach is acceptable to patients and does not induce anxiety or impair quality of life.

Patients with asymptomatic, low-volume metastatic disease may benefit from a period of observation free from the toxicity of systemic therapy without compromising survival. Further prospective studies with biomarker validation are required to define the patients most likely to benefit from this approach.