Combined modality therapy versus chemotherapy alone as an induction regimen for primary central nervous system lymphoma: a cost-effectiveness analysis

Background: In immunocompetent patients with primary central nervous system lymphoma (PCNSL), combined modality therapy (CMT) using high-dose methotrexate and radiotherapy (WBRT) has improved response rates compared with chemotherapy alone. The trade-off is delayed and potentially devastating treatment-related neurotoxicity (NT).

Methods: A cost-effectiveness analysis using a Markov model compared CMT with chemotherapy alone in age-stratified patients with PCNSL. Baseline probabilities were derived from a systematic literature review. Direct and lost productivity costs were collected from a Canadian perspective and presented in Can$ in 2011. Outcomes were life expectancy, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio.

Results: The quality-adjusted life expectancy was 1.55 QALYs for CMT and 1.53 QALYs for chemotherapy alone. In younger patients (aged <60 years), CMT yielded 2.44 QALYs, compared with 1.89 QALYs for chemotherapy alone, yielding an expected benefit with CMT of 0.55 QALYs or 6.6 quality-adjusted months. The CMT strategy dominated in younger patients, as it was Can$11 951 less expensive than chemotherapy alone. The chemotherapy-alone strategy dominated in older patients, as it was Can$11 244 less expensive than CMT, and there was no difference in QALYs between the strategies. The model was robust in sensitivity analyses of key variables tested through the plausible ranges obtained from costing sources and published literature.

Conclusion: The preferred induction strategy for younger patients with PCNSL appears to be CMT, which minimized cost while maximizing life expectancy and QALYs. This analysis confirms that the preferred strategy for older patients is chemotherapy alone.