Reproducible Evidence: Practices to Enhance and Achieve Transparency (REPEAT): Study 16 - "Use of tamoxifen and aromatase inhibitors in a large population-based cohort of women with breast cancer"

Date of ISAC Approval: 
Lay Summary: 
Science should be replicable. The methods section in publications describe how research is conducted. This protocol is part of the REPEAT Initiative, a project that is attempting to replicate a sample of published research studies using information provided in the publications. REPEAT is focused on studies using observational healthcare data from electronic health records or administrative claims to generate scientific evidence. The goal is to better understand what information is missing in publications that prevents replication of the published results. This project will evaluate how commonly important decisions in research process design are not clearly reported as well as how lack of impacts ability to replicate study findings. Our results will inform future policies and guidelines for reporting on healthcare database research. This protocol focuses on one sampled study: "Use of tamoxifen and aromatase inhibitors in a large population-based cohort of women with breast cancer" by Huiart and colleagues. The Huiart paper compares the percentage of women with breast cancer who stop treatment with tamoxifen or aromatase inhibitors (drugs used to treat breast cancer) within 5 years. We will replicate this study based on methods reported in the publication.
Technical Summary: 
This objective of this protocol is to replicate the study: "Use of tamoxifen and aromatase inhibitors in a large population-based cohort of women with breast cancer" by Huiart et al based on methods reported in the publication and appendices. We have created a checklist of specific study implementation parameters based on a comprehensive catalogue outlined in a consensus paper endorsed by the International Society of Pharmacoepidemiology and the International Society of Pharmacoeconomics and Outcomes research. We will start by reviewing the paper to identify which parameters from the catalogue are reported. We will then replicate the study population and analyses based on the study design and implementation parameters extracted during review. The Huiart paper describes the percentage of women from 1998 to 2008 with breast cancer who discontinue treatment with tamoxifen and aromatase inhibitors within the first 5 years. We will focus on replicating the outcome of percentage of patients with breast cancer who discontinue treatments within 5 years over the same study period. All patients were followed from cohort entry (date of first prescription) to the end of treatment (up to 5 years), death from any cause, breast cancer recurrence or contralateral breast cancer, thrombo-embolic event, or endometrial cancer, whichever came first. Non-persistence to treatment was defined as the first treatment discontinuation longer than 3 months. Time to treatment discontinuation was calculated using Kaplan-Meier estimates.
Health Outcomes to be Measured: 
Percentage of tamoxifen or aromatase inhibitor users who discontinue treatment within 5 years.

Dr Shirley Wang - Chief Investigator - Harvard University
Elisabetta Patorno - Collaborator - Brigham & Women's Hospital
Elizabeth Garry - Collaborator - Aetion, Inc
Jeremy Rassen - Corresponding Applicant - Aetion, Inc
Jessica Franklin - Collaborator - Brigham & Women's Hospital
Ms Krista Huybrechts - Collaborator - Brigham & Women's Hospital
Dr Sebastian Schneeweiss - Collaborator - Aetion, Inc