Description
- Abstract:
- Background. Rituximab-based immunochemotherapy for Waldenström macroglobulinemia / lymphoplasmacytic lymphoma (WM/LPL) showed high response rates in single-arm trials, but comparative data are lacking. We compared overall survival and select toxicity outcomes after various immunochemotherapy regimens by applying causal inference methods to a population-based cohort. Patients and methods. From the linked Surveillance, Epidemiology and End Results-Medicare database, we extracted records of patients age 65 or older, who initiated chemotherapy for WM/LPL in 1999-2013. We applied a propensity score-based causal inference method (multiple-imputation using two subclassification splines) to minimize bias between treatment arms, and conducted 3 analyses comparing: 1) patients treated with or without rituximab, 2) patients treated with rituximab monotherapy or with combination immunochemotherapy, and 3) regimens based on classic purine analogues (mainly fludarabine) or alkylators (mainly cyclophosphamide). Outcomes included overall survival (OS), risk of hospitalizations, transfusions, and plasmapheresis, reported as adjusted estimates from Bayesian models with 95% confidence intervals (95%CI) Results. Among 1,310 patients with WM/LPL, 78.5% received rituximab as part of upfront therapy. After balancing study arms with regard to available confounding variables, patients who received rituximab had significantly better OS (hazard ratio, 0.62, 95%CI, 0.55-0.71) and lower risk of transfusions (risk difference -3.3%, 95%CI, -6.3 to -0.3) than those who did not, without a statistically significant difference in hospitalizations or plasmapheresis. We observed no significant difference in OS (hazard ratio, 0.91, 95%CI, 0.79-1.04) between rituximab monotherapy and combination immunochemotherapy, but rates of all 3 toxicity outcomes were lower with rituximab alone. Neither survival (hazard ratio, 1.10, 95%CI, 0.92-1.32) nor toxicity outcomes differed significantly between regimens based on purine analogues or alkylators. Conclusion. The survival advantage strongly supports rituximab as part of upfront therapy for WM/LPL, without evidence of increased short-term morbidity. Contrary to historical data, regimens with either purine analogues or alkylating agents result in similar outcomes.
- Notes:
- Thesis (Sc. M.)--Brown University, 2017
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Citation
Chen, Chang,
"Comparative Outcomes of Treatment Regimens in Waldenström Macroglobulinemia"
(2017).
Biostatistics Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z06T0K24
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Biostatistics Theses and Dissertations
Theses and Dissertations for the Biostatistics department....