Breast Cancer Primer
This interview with Larry Norton, MD of Memorial Sloan Kettering, published in MedScape, is an excellent overview of breast cancer. If you have ever wondered about the basics of breast cancer biology and treatment, spending a few minutes with Dr Norton will be time well spent.
I am giving you the beginning and then a link to read more or to watch a video of the interview:
Larry Norton: From A to B in Breast Cancer
How Cancer Cells Set Up Shop in the Axilla
Dr. Miller: Let's start with local therapy.We saw another important phase 3 study in local therapy this year that looked at women who had a positive sentinel node and randomly assigned them to additional axillary surgery or focused axillary radiation, extending to a dedicated axillary field. In this day and age, who still needs a full axillary dissection?
Larry Norton, MD: It is a very interesting topic because it has 2 parts. One is the practical aspect of how to take care of patients. The other part is the theoretical consideration. When I was in medical school, we knew how breast cancer spread. It gained access to the lymphatics, and the lymphatics took it to the axilla. The axilla acts as a filter. It broke through the filter to the rest of the body. That was always the concept behind a radical mastectomy: that you remove everything, getting all of the cells out, so that they don't spread to any other part of the body. Starting with the work of Bernie Fisher and all of the work of the National Surgical Adjuvant Breast and Bowel Project, and the evolution of thought about the anatomy of metastases, clearly that is not what happens. The simple linear-flow concept of how breast cancer spreads is not really applicable.
On the other hand, we know that there is a linear flow, because that is what sentinel mapping tells us. With sentinel mapping, we know which node is picking up the drainage from the breast, and if that is clean, it is unlikely that any other nodes are positive. We have this complicated biological problem that can be sorted out with site-specific metastases.
Cancer cells don't go somewhere because of mechanical pressures. They probably have access to the entire body, and what matters is where they form colonies and stay, which in turn depends on the microenvironment.
There is a signal in the cancer cell -- a signature. We know a lot about that signature already, but we are learning more.