Comparative Analyses
Modeling future mortality benefits associated with recent treatment advances
While the results of the New England Journal of Medicine paper, described as a landmark study, considered the benefits of what might be termed “first generation” chemotherapy and tamoxifen, new chemotherapy regimens, including anthracycline-based regimens and taxanes, aromatase inhibitors for ER positive breast cancers, and trastuzumab for HER-2 positive tumors, have dramatically improved prognosis for breast cancer patients. Six CISNET groups have joined together to model the current and future effect of treatment advances on breast cancer mortality by incorporating the benefits of each regimen from clinical trials, the subset of patients potentially eligible to receive each of the regimens, and the current and projected usage patterns.
First-, Second-, and Third-Generation Breast Cancer Chemotherapy Regimens
Changes in breast cancer chemotherapy regimens over time and classification of chemotherapy into categories with similar efficacy.
Understanding the use of hormone replacement therapy on breast cancer incidence and the natural history of disease
A report by the Women's Health Initiative showed an increased risk for breast cancer in women taking hormone replacement therapy and resulted in a striking drop in the use of hormone replacement therapy among postmenopausal women in the United States. A contemporaneous decline in incidence rates of primarily estrogen receptor (ER) positive breast cancer among women aged 50-69 was reported by CISNET investigators (Ravdin 2007). This analysis of the SEER data demonstrated that clinical trial results affecting health behaviors could directly translate to a decrease in breast cancer incidence in the population. Since this initial pivotal report, CISNET investigators have joined with researchers from Kaiser Permanente to acquire the data needed to directly model the impact of hormone use on the natural history of disease to provide further insight into how hormones affect risk and how quickly risk returns to a background level after discontinuing hormone use.
Trends in Breast Cancer Incidence and Use of Hormone Replacement Therapy
Quarterly incidence of breast cancer in women aged 50-69, according to (A) estrogen receptor status and (B) the number of prescriptions for hormone replacement therapy. Copyright © 2007 Massachusetts Medical Society. All rights reserved.
Modeling various screening scenarios to inform clinical recommendations for mammography use
There has been considerable debate related to breast cancer screening recommendations, particularly related to screening women aged 40-49 and 70 or older. While clinical trial results provide the evidence on which mammography recommendations are based, policy makers have turned to modeling to fill gaps in evidence that cannot be directly addressed from clinical trials and epidemiological studies. In a unique modeling effort, the CISNET breast cancer groups worked closely with the U.S. Preventive Services Task Force (USPSTF) to provide modeling input to supplement USPSTF's typical evidence review for updating breast cancer screening recommendations. This included modeling the added benefits and harms of screening at earlier and later ages and varying the time interval between successive screening exams. Modeling significantly contributed to the discussion of harms and benefits of various screening schedules and the intent is to publish CISNET modeling results along with the updated screening guideline.
