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As you'll recall, when we last left Jane, her surgeon (Dr. Smith) had removed Jane's breast tumor and had also done a sentinel lymph node biopsy. (For a quick refresher on that procedure, pop back to Episode 13.) Jane's breast tumor had been removed with a good margin. She and Dr. Smith were both pleased.
The pathologists also took some of the tissue from Jane's tumor and performed special tests on it. Those tests were designed to show if the cancer cells were producing particular proteins. If they were, it could influence what treatments would be helpful for Jane.
One of the tests was used to reveal if Jane's breast cancer cells had estrogen receptors on them. Estrogen is a hormone that all of us have floating around our systems. Women tend to have more of it then men. It has a variety of functions throughout the body. It turns out that many breast cancers have estrogen receptors built into their cell walls. Estrogen can fit into those receptors, the way a key fits into a lock.
Once the estrogen molecule has bound to the estrogen receptor, it signals the cancer cell to accelerate its growing and dividing. Which is exactly what we DON'T want cancer cells to do.
Fortunately, we have medications that can prevent this from happening. Depending on the medication, they can work in two different ways:
1. Block the estrogen receptor. This is the equivalent of stuffing bubble gum into the door lock of your high school principal's Buick, so he comes out at the end of the day and can't get his car door open. (Not that I've ever done such a thing--I'm only speaking hypothetically.)
2. Reduce the amount of estrogen that the body is producing. This means there are a lot of empty locks without keys to fit into them.
Giving one of those medications has been shown to reduce the risk of the cancer coming back. If the cancer cells have estrogen receptors on their cell surfaces, we physicians will describe that cancer as ER-positive. (The ER stands for estrogen receptor.) If the cancer cells lack that estrogen receptor, then the cancer is ER-negative.
There are other receptors that pathologists will look for on breast cancer cell surfaces. One of them has the crazy name HER2/neu. (No, I'm not making that up.)
Some breast cancers have very high concentrations of the HER2/neu molecules on their cell surfaces. For patients who have that (their cancers are HER2/neu-positive), it's been shown that giving the medication Trastuzumab in combination with conventional chemotherapy will reduce the risk of the cancer recurring.
One of the big questions we try to answer by evaluating these sorts of receptors on the cancer cell surfaces is, should the patient get chemotherapy or not? We know that for a lot of breast cancers, chemotherapy can dramatically reduce the risk of the cancer recurring and improve the patient's likelihood for being alive and cancer-free five or ten years down the road. However, that's not true for every breast cancer, and because chemotherapy can have significant side effects, we'd prefer to only give it to the patients who need it. This is an area of VERY active research, so expect this to change rapidly in the near future. However, as of this writing, the breast cancer patients who would likely benefit from chemotherapy include those who are:
- Have involved lymph nodes
If you have one or more of those factors, then the studies suggest you would probably benefit from chemotherapy. However, even if your cancer is ER-positive, HER2/neu-negative, and doesn't have involved lymph nodes, there's still a chance you might benefit from chemo. For those patients, there's a special test called the Oncotype DX test that's done. That test evaluates 21 separate genes in the cancer cells, and from that analysis calculates the likelihood that chemotherapy would be of benefit. Armed with that analysis, oncologists then can make better recommendations for who should get chemotherapy. So, really, there should be one more item on that list above:
- Have a high Oncotype DX score
Sometimes, other factors play a role in helping oncologists determine who should get chemotherapy and who shouldn't. They also consider the patient's cancer stage, the tumor size, and the overall health status of the patient.
The pathologists found that Jane's cancer was ER-positive and HER2/neu-negative. If she hadn't had lymph nodes involved, she would have been a candidate for the Oncotype DX test to determine if she should get chemo or not. As it happened, she did have lymph nodes involved, so that test was not done. (It's results wouldn't have mattered--she was going to get chemotherapy no matter what it showed.)