Breast cancer treatments have also undergone extensive changes within the past decade. Much of the changes in treatment were related to the changing paradigms of the biology of breast cancer.
The Halstedian paradigm of breast cancer was one that advocated that the disease spread in an orderly and centrifugal fashion. First, a tumor grew locally, infiltrated the regional lymphatics in a direct and contiguous manner, and then spread distantly. Regional lymph nodes were thought to serve as a barrier for the spread of tumor cells, and the bloodstream was thought to be of little significance as a route of tumor dissemination.
The Halstedian paradigm, which began at the end of the nineteenth century, formed the basis for the radical mastectomy as the preferred treatment for breast cancer. Most recently, both clinical and biologic observations suggest that occult metastases may be present in some women at diagnosis so that their disease will be minimally affected by local treatment. There is evidence that the rate of local and distant recurrence is decreased by the use of both adjuvant chemotherapy and adjuvant tamoxifen.
Data from ten randomized clinical trials demonstrated that adjuvant chemotherapy reduced the rate of recurrence by approximately one third. However, the Consensus Conference concluded that these studies did not have large enough numbers nor was their follow-up after treatment of sufficient duration to determine whether there was an overall improved rate in breast cancer survival among patients with negative nodes. In summary, clinical and biologic observations of the natural history of breast cancer have led to modifications in treatment that were originally based on the longstanding Halstedian paradigm.
Two alternative paradigms: one that supports systemic treatment, and the second which advocates a combination of local and systemic therapy, have challenged the Halstedian view. As research continues in the search for more effective methods of treatment, women who are diagnosed earlier will continue to survive and live longer with the disease of breast cancer. This environment of extended survival has opened the way for women who are of childbearing age to consider pregnancy after having breast cancer