Analytical strategies for characterizing chemother

Authors: Cami S Sima Katherine S Panageas Glenn Heller Deborah Schrag

Publish Date: 2012/08/06

Volume: 8, Issue: 1, Pages: 37-51

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Abstract

To inform assessments of the quality of cancer care we describe analytical approaches to characterizing trends in diffusion of chemotherapy drugs subsequent to their US FDA approval The economics and medical literature provide two distinct sets of empirical methods for investigating diffusion of innovations aggregate models which use the level of market penetration as an estimator of diffusion and disaggregate models which evaluate diffusion based on the time required for different individual units to adopt innovations When patientlevel populationbased data are available disaggregate methods make the best use of the available information We propose a method that employs timetoevent techniques to describe the probability of utilization of a drug within a specified timeframe subsequent to the diagnosis of cancer By mapping the relationship between this probability and calendar time of a patient’s diagnosis we can assess trends in diffusion Our approach accounts for the dependent censoring for death as well as for the clustering of patients within physicians The method proposed is illustrated using Surveillance Epidemiology and End Results SEERMedicare data applied to two case studies gemcitabine approved for stage III/IV pancreatic cancer and irinotecan approved as a secondline therapy for stage IV colorectal cancerThis research was supported by a grant from the National Cancer Institute R21 CA98353 The authors have no conflicts of interests that are directly relevant to the contents of this study We acknowledge the efforts of several groups responsible for the creation and dissemination of the SEERMedicare linked database including the Applied Research Branch Division of Cancer Control and Population Sciences National Cancer Institute the Office of Strategic Planning and the Office of Information Services Center for Medicare and Medicaid Services the Information Management Series and the SEER program tumour registries

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