Fewer Breast Cancer Patients May Need Chemo

Study: Fewer Women with Breast Cancer May Need Chemo

Many of you are familiar with the Oncotype DX test that examines a newly diagnosed woman’s tumor cells to help determine whether she will benefit from chemotherapy. This test is only relevant to women who have ER positive breast cancers.

Examining the expression of 21 genes, the test returns a recurrence risk score in the low, intermediate or high range. It has been fairly straightforward for most women, whose scores are in the low ranger, and their doctors to move right to hormonal treatment and omit chemotherapy. For women in the high risk group, the opposite is true, and most women are easily persuaded that chemo in addition to hormonal therapy will help reduce their personal risk of recurrence. The problem has been the middle group.

This was my own situation when my second breast cancer was diagnosed in 2005. It was more complicated because the Oncotype DX was very new so there was much less experience to support its value. Additionally, my second cancer appeared while I was taking an AI for the first one. To my own non-doctor head, it seemed pretty obvious that hormonal therapy alone was not such a good plan. I had chemo, too.

In the years since then, I have talked with many women who were struggling to make this decision. It usually came down to how frightened they were by the prospect of chemotherapy. Sometimes there were other factors (e.g. other medical problems) that swayed them and their doctors one way or another. Most of the time, however, it was a gut decision. Which way is going to enable me to sleep better at night now and 10 years from now? 

It now appears that more women with early-stage breast cancer may be able to avoid chemotherapy.

Results from a large clinical trial called TAILORx showed that more women with early-stage breast cancer may now be able to avoid chemotherapy after surgery. The women who participated in the study had hormone receptor-positive, HER2-negative, axillary node-negative breast cancer, which is the most common type of breast cancer.

Breast cancers that have estrogen receptors and/or progesterone receptors but do not have HER2 are known as hormone receptor-positive, HER2-negative. Estrogen and progesterone receptors are proteins found in and on cells. Cancers with these receptors may depend on the hormones estrogen and/or progesterone to grow. HER2 is another type of specialized protein on the surface of breast cells that also affects tumor growth. Axillary node-negative breast cancer means that the lymph nodes in the armpit area do not contain cancer.

This type of breast cancer is typically treated with hormone therapy. Women who have a high risk of a breast cancer recurrence also receive chemotherapy, called adjuvant chemotherapy. A recurrence is when cancer comes back after treatment. A test called the 21-gene expression assay (Oncotype DX Breast Recurrence Score) is used to find out a woman’s risk of having a recurrence. The test is done using a sample of the tumor taken during a biopsy. A higher score means a higher risk of recurrence. Usually, women with a Breast Recurrence Score up to 10 receive only hormone therapy. Women with a score of 26 to 100 receive both hormone therapy and chemotherapy. But there is currently no standard of care for a mid-range score of 11 to 25. It is estimated that about 40% of women with a mid-range score currently receive chemotherapy. Side effects from chemotherapy may include nausea, vomiting, pain, and hair loss and such long-term problems as infertility and neuropathy.

Read more from the American Society of Clinical Oncology (ASCO): 

https://www.cancer.net/blog/2018-06/asco-annual-meeting-2018-less-treatment-needed-some-patients-with-breast-cancer-and-kidney-cancer?