Optimal number of cycles of bendamustine as initial chemoimmunotherapy for older patients with follicular lymphoma

Bendamustine is among the most commonly used chemoimmunotherapies for patients with follicular lymphoma. It is typically delivered with a goal regimen consisting of 6 cycles, but it is possible that treatment goals could be achieved with fewer cycles, particularly in older patients. We used data from the SEER-Medicare linkage to evaluate the overall survival of patients with follicular lymphoma receiving 3 to 4 versus 5 to 6 cycles of bendamustine. Patients receiving 1-2 cycles of bendamustine chemotherapy were not included. Patients receiving 5-6 cycles of bendamustine were significantly younger (mean 75.0 vs 76.2 years, p<0.01) and had fewer comorbidities by NCI comorbidity index (mean score 1.7 vs 2.0, p=0.05) than those receiving 3-4 cycles of bendamustine, and on univariate analysis exhibited significantly lower risk of death (HR = 0.75, 95% CI 0.57 – 0.98, p=0.04). However, multivariate analysis controlling for age and comorbidity did not reveal a significant association between overall survival and number of cycles of bendamustine (HR: 0.87 95% CI 0.66 – 1.15, p = 0.33). Limitations inherent to use of data such as these for causal inference are acknowledged. Nonetheless, these analyses suggest some older patients with FL achieve satisfactory survival outcomes even with lesser bendamustine exposure, and future efforts to prospectively identify such patients are warranted.