A population-based study of prognosis in advanced stage follicular lymphoma managed by watch and wait.

Watch and wait (WAW) is a common approach for asymptomatic, advanced stage follicular lymphoma (FL), but single-agent rituximab is an alternative for these patients. In this nationwide study we describe the outcome of patients selected for WAW. A cohort of 286 out of 849 (34%) stage III-IVA FL patients seen between 2000 and 2011, were managed expectantly and included. The 5-year progression-free survival (PFS) was 35% [95% confidence interval (CI) 29-42]. The 10-year overall survival (OS) was 65% (95%CI 54-78), and the cumulative risk of dying from lymphoma within 10 years of diagnosis was 13% (95%CI 7-20). Elevated lactate dehydrogenase and > four nodal regions involved were associated with a higher risk of lymphoma treatment and death from lymphoma. The WAW patients and a matched background population had similar OS during the first 50 months after diagnosis (P = 0·7), but WAW patients had increased risk of death after 50 months (P < 0·001). The estimated loss of residual life after 10 years was 6·8 months. The 10-year cumulative risk of histological transformation was 22% (95%CI 15-29) and the 3-year OS after transformation was 71% (95%CI 58-87%). In conclusion, advanced stage FL managed by WAW had a favourable outcome and abandoning this strategy could lead to overtreatment in some patients.