From Mark Levine, the Doc with Pink Tights
Recent News Flash: “Chemotherapy Can be Avoided”
In last month’s article “Living with your New Normal,” I indicated my discussion about what life is like after completion of initial therapy would continue in the next edition. However, as is often the case, circumstances and priorities change. I’ll return to New Normal next month.
During the first week of June, you may have noticed there was a great deal in the news about breast cancer; specifically, that many women would no longer require chemotherapy. I cringed when I heard how this information was being presented by the media. I was aware of the background and context of this new information. I feared that many patients would be confused. Unfortunately, it is not that simple. I will try to explain.
Typically, when a patient has a lump or an abnormal mammogram, a biopsy is done to diagnose breast cancer. Then surgery, either lumpectomy or mastectomy, is performed. This is usually followed by a procedure that examines the lymph nodes under the arm to see if cancer has spread to the nodes.
The key factors the oncologist considers to determine what treatments to administer are the estrogen receptor (ER), the size of the cancer and the grade (how nasty the cancer looks under the microscope), and whether there is cancer in the lymph nodes.
If the ER is positive, estrogen blocking pills e.g. tamoxifen or an aromatase inhibitor is given. If the ER is negative, this type of treatment will not work. Factors that indicate a higher risk of the cancer coming back after initial treatments are large tumours (greater than 5cm), cancer in the lymph nodes, grade III, and ER negative. Chemotherapy is often recommended if any of these factors, called prognostic factors, are present.
But what about the situation where there is no cancer in the nodes and the tumor is ER positive? In general, the prognosis is very good and estrogen blocking treatment is standard. But a few of these cancers can still be bad actors and still come back and spread.
Approximately eight years ago, we began to test ER positive, lymph node negative breast cancer routinely to gain additional information on prognosis. This test, called Oncotype Dx, examines 21 genes, called a gene signature, which can provide information on prognosis. This is extra information beyond the usual factors e.g. size, grade.
The Oncotype Dx test provides a risk score: 0-18 indicates low risk for recurrence, 18-30 indicates intermediate risk, and greater than 30 indicates high risk. Usually if the cancer is low risk, only estrogen blocking tablets are recommended and if it is high risk, chemotherapy is added to estrogen blocking pills.
But we were not sure about what to do with cancers that had an intermediate score. We would discuss with patients the prognosis of intermediate risk breast cancer, the added benefit of chemotherapy over estrogen blockers, and side effects. We would try and help them make the best decision for themselves.
The TailorX clinical trial was started many years ago and the results were recently reported at the American Society of Clinical Oncology meetings in Chicago. Over 10,000 women with node negative, ER positive breast cancer with intermediate Oncotype Dx scores were randomly allocated to estrogen blocking tablets versus estrogen blocking tablets plus chemotherapy.
After more than five years of follow-up, the overall results showed no difference in recurrence rates or survival between the two groups. Hence adding chemotherapy did not provide additional benefit. Perhaps there was a benefit of chemotherapy (but by no means definitive) in young patients (less than 50) and those with scores at the very upper end of the intermediate range, e.g. around 25.
Approximately 60 per cent of breast cancers present as node negative, 20 per cent as node positive, 15 per cent as locally advanced and 5 per cent as metastatic. Approximately two thirds of node negative breast cancers are ER+.
Hence, if we consider an example of 100 newly diagnosed breast cancer patients attending clinic for the first time, 60 patients will have node negative breast cancer, 40 of whom will also be ER positive. We know that if we do the Oncotype Dx test on these 40 cancers, about 20 will have an intermediate risk score. It is these 20 patients who now can avoid having chemotherapy added to estrogen blocking drugs based on the results of the TailorX trial.
It is important that you understand the recent study results do not apply to ER negative, or node positive, or locally advanced, or metastatic breast cancer.