Introduction
US breast cancer mortality was rising slightly until 1990, but has since declined significantly since then.
In order to plan new cancer control strategies, it is essential to understand the population impact of interventions
that began in the 1970s and 80s. Effective multi-agent chemotherapy regimens were first introduced in the mid-
and late 1970s. While initially used in later stage disease, as these regimens' safety and efficacy were further
established it has increasingly been used in earlier stages. The use of multi-agent chemotherapy has remained
limited in older patients. Tamoxifen was introduced in the early 1980s, and its use has grown steadily among
estrogen receptor-positive patients, regardless of age. It has been shown that longer administration of Tamoxifen
is more effective, and the length of administration has grown from 2 to 5 years. The combined use of Tamoxifen
and multi-agent chemotherapy is more effective than either modality used individually. The use of the combined
therapies began in the late 1980s. At the same time that adjuvant therapy was becoming established in the early
1980s, the use of mammography became more widespread. The speed of the dissemination of mammography was rapid
between 1987 and 1992, and then slowed in the mid 1990s.
About the Breast Base Case
All members of the Cancer Intervention and Surveillance Modeling Network Consortium who model breast cancer
are collaborating on a set of common simulations to address the impact of mammography and adjuvant therapy on
trends in breast cancer mortality from 1975-2000. The purpose of this modeling effort is to partition observed
mortality trends into components associated with the increased use of adjuvant therapy, mammography, and background
changes in underlying risk. Certainly the current controversy surrounding mammography has made this a timely
topic, especially as we attempt to weigh any mortality gains against its downsides (overdiagnosis, false positives,
etc).
These simulations formed the basis of a special Journal
of the National Cancer Institute Monograph
on the subject. The monograph includes a description
of each model, as well as a synthesis of results from
the common simulations, depicting model differences and
similarities over the results.
(View
monograph)
Results from the breast base case were published in the New England Journal
of Medicine in October 2005 (view
abstract).
Breast Base Case Parameters
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