Wellness Center

Chemo Unnecessary for a Specific Breast Cancer

Chemotherapy might be ineffective and unnecessary for women with a specific type of breast cancer – estrogen-dependent, lymph-node negative breast cancer. This kind of breast cancer needs estrogen to grow but has not spread to the lymph nodes.

Currently, many women with this type of breast cancer in the United States do receive chemotherapy in addition to hormonal therapy. But, research results suggest that almost half of the 43,000 U.S. women diagnosed every year are at low risk for recurrence and may not need to go through the discomfort and side effects of chemotherapy.

A test can now predict both the risk of breast cancer recurrence and might identify women who will benefit most from chemotherapy, according to research supported by the National Cancer Institute (NCI).

Using samples from 447 patients and a collection of 250 genes in three independent preliminary studies, 16 cancer-related genes were found that worked best. The scientists created a formula that generates a "recurrence score" based on the expression patterns of these genes in a tumor sample. Ranging from 1 to 100, the recurrence score is a measure of the risk that a given cancer will recur.

Using the recurrence score, women can be divided into three groups: low risk (a score of less than 18), moderate risk (18-30), and high risk (a score of 31 or higher). During the research period, these risk group divisions correlated well with the actual rates of recurrence of breast cancer after 10 years.

The results validate the ability of the recurrence score to predict risk of recurrence. In the low-risk group, there was a 6.8 percent rate of recurrence at 10 years; 14.3 percent in the intermediate, and 30.5 percent in the high risk category. The rates of recurrence increased continuously as the recurrence score increased, up to a recurrence score of 50. These trends held across age groups and tumor size.

Summary

Women with low risk of breast cancer recurrence – about half of the women in the recent study – did not appear to derive much added benefit from chemotherapy.

Sources:

1. Molecular Test Can Predict Both the Risk of Breast Cancer Recurrence and Who Will Benefit From Chemotherapy, National Institutes of Health.

2. Paik S et al. A multigene assay to predict recurrence of node-negative, estrogen-receptor-positive breast cancer in tamoxifen-treated patients. New England Journal of Medicine; 351(27).

This information is provided for educational purposes only and is not intended to be a substitute for professional medical advice or diagnosis of specific medical conditions. You should seek prompt professional medical attention if you have a particular concern about your health or specific symptoms.