Diagnosis and Treatment of Breast Cancer 4
Tumor size does correlate with outcome. It’s not the strongest predictor of outcome but it certainly correlates and this just graphs tumor size against percent of disease free patients in five years. You can see as the tumor gets more than 5 cm, the chances to remain disease free gets less than 50%.
Nodes is the next way to stage and you either have negative nodes or positive nodes or N2 disease is nodes that have grown together or are matted. N3 disease is internal mammary nodes which, in fact, we don’t stage for very well but usually in patients who present with a real medial lesion, I will do a CAT scan to try and better assess those internal mammary nodes.
This correlates lymph nodes to disease free survival and lymph nodes are the biggest predictor of outcome in breast cancer. The predictive value increases with every positive node in a negative way. So if this is just the number of positive nodes against percent of disease free patients at five years, you can see that your chances to be disease free with ten or more positive nodes is less than 20%.
This is another way to look at that. If you have no positive nodes, your chance for relapse is about 20%, one to three about 60% and more than four positive nodes puts your chances to relapse in the 85% range. This, of course, has led us to target these patients with four or more positive nodes with more aggressive therapy such as high dose chemotherapy and autologous peripheral blood stem cell rescue or bone marrow rescue or get them into trials of more aggressive therapy.
If you have metastatic disease, then that makes you an M1. So it’s either you have metastatic disease or you don’t. Then you put these T and M classifications together. There’s only one way to be a Stage I breast cancer and that’s to have a tumor less than 2 cm, a T1 lesion, no nodes and no metastases. Anytime you have metastases, no matter what your T or your N, you’re a Stage IV.
Stage II can be all kinds of things and it’s easier to remember that Stage II is anything that’s not Stage I, III or IV. Stage III disease is anytime you have a T4 lesion, you’re going to be a Stage III. Let’s look at Stage III. Any T4 will put you in a Stage III. Any T3 with positive nodes is going to make you a Stage III. Any N2 disease will make you a Stage III and all the rest will be a Stage II. So the minute you have positive nodes, it makes you in Stage II or III. If it’s not N2 disease and it’s not a T4 lesion and it’s not a T3 lesion, you’ll be a Stage II.
If you go back and look at it, it makes a lot of sense. The only way you can be a T3 and still be a Stage II is not to have any positive nodes and that doesn’t happen very often. So all the T1 and N1 combinations make you a Stage II. Anytime you have nodes that aren’t N2 disease, you’ll end up being a Stage II usually.
This graph just shows you that this staging actually is pretty predictive and this is overall survival across years at 10 years. This black line at about 80% is Stage I disease. So no nodes tumor, 2 cm or less, this falls to about 50%. Anytime you have positive nodes, these are usually microscopically positive nodes, are a tumor that is greater than 2 cm. This line, Stage III disease, usually a big tumor or large matted nodes, puts you down to about 30-35% and you can see that there are no long term survivals in patients who have metastatic disease.
There are other prognostic features that we also consider. The one that’s most talked about, of course, is the estrogen and progesterone receptors. If you’re estrogen receptor positive and/or progesterone receptor positive you are less likely to relapse and have metastatic disease or if you do it takes a longer time. The S phase, the percent of cells that are in a dividing phase, usually determined by cell sorting, may have a predictive value and it’s becoming clear that the overexpression of the gene product from the epidermal growth factor gene or HUR2-nu is an independent predictor for outcome, independent of these other factors, and is probably in the future going to be increasingly used to predict risk of breast cancer.
Well, we use all these risk factors to decide who we think needs systemic therapy to try to eradicate microscopic disease and hopefully change that person from going on and relapsing from breast cancer to being cured of breast cancer. Clearly, when you saw a Stage II line that dropped right to 50%, all those patients are at high risk for relapse and they would be thought to need some sort of systemic adjuvant therapy to treat microscopic disease. So node positive patients, some sort of systemic adjuvant therapy.