Coffee with Komen – Breast Cancer Staging: Significant Changes Coming Soon
by Timothy Goedde, MD
Breast Surgeon, Community Health Network
It is a frequent question I’m asked by my breast cancer patients: What stage am I in?
Why haven’t I told them up front? I stopped thinking about stage many years ago, because it really didn’t provide me with the information I need.
Let’s back up and review how stage is determined.
The stage of a breast cancer represents the “amount” or “tumor burden” of a patient’s cancer. A 3 cm cancer has more tumor burden than a 1 cm cancer, and has a higher stage. A 1 cm cancer that has not spread to lymph nodes has a smaller tumor burden than a 1 cm cancer that has spread to the lymph nodes, therefore its stage would be smaller.
The current staging system includes only three factors, all based on the anatomy or extent of the cancer. It is called the TNM system: T stands for tumor size, N stands for nodal involvement, and M stands for metastasis (distant spread, e.g. lungs, liver, bone, brain).
A small, 1 cm cancer that hasn’t spread to the lymph nodes or distant spread would be called Stage I. A 1 cm cancer that has spread to lymph nodes, but not to distant sites, would be called Stage II.
This TNM system has been around since 1959 and has been modified frequently; we are currently on our seventh version. The latest version (#7) was changed in 2010 and the next version (#8) goes into effect January 1, 2018.
The stage of a breast cancer is supposed to do two things. First, it should define the prognosis of a patient. Second, it should help guide treatment.
As new information has developed over the past several decades, it is apparent that the old staging system was not very good at doing either. Breast cancer survivors reading this already knew this intuitively. Most are aware of terms such as “responds to hormones” or “triple negative” or “has low oncotype score.”
How many patients have waited weeks frustratingly after surgery for their Oncotype Score to return before they know whether they will get chemotherapy or not? Or the patient who knew within days that she would begin chemotherapy because she is triple negative?
So, if some Stage I patients get chemotherapy and some don’t get chemotherapy, then what is the purpose of the “stage” to begin with? And if some Stage I patients have a chance of cure approaching 100% and some stage I patients have a chance of cure hovering around 70%, then what good is the stage for?
I mentioned specific examples in which the old stage neither predicted the prognosis nor the treatment. The 8th edition of staging goes a long way in correcting these deficiencies. It still includes the TNM system but adds biomarkers. Biomarkers are “things” that are measured in the cancer tissue itself and includes: estrogen receptors, progesterone receptors, Her2neu amplification, and occasionally the Oncotype DX recurrence score.
These biomarkers are very important factors and allow us to “subtype” the cancer. The three biomarkers that are always measured now include ER, PR and Her2neu. The best combination of these three factors would be ER+, PR+, Her2neu negative. The worst combination is when all three are negative (triple negative). To give an example, a previous Stage I cancer that is triple negative will now be called stage IIA. A previous stage II cancer, with the three best biomarkers, will likely be called Stage IB.
These biomarkers, as well as the TNM stage, have a huge impact on the treatment of the patient’s breast cancer. For example, patients whose cancer is ER and/or PR positive will get anti-hormonal therapy (e.g. Tamoxifen, Arimidex, Faslodex, etc). Patients who are Her2neu positive are likely to receive Herceptin in addition to chemotherapy. Herceptin is an antibody to the Her2neu products.
This is a general overview, as there are many nuances to the new and old staging that I did not cover. Rest assured, if you were diagnosed in the past your treatment WAS based on all factors, including the equally important biomarkers.
Former breast cancer patients will not be re-staged, as it would be too complicated and would not change how they were treated in the past nor change their prognosis for the future. It is also highly likely that we will see frequent modifications to the staging system in the future as new information and new biomarkers are discovered.