New test predicts whether chemotherapy will be effective

Breast cancer is usually diagnosed at an early stage, before it has spread. However, one in three of these women and men will eventually experience a recurrence. That is why, in many cases, follow-up treatment with chemotherapy or hormone therapy is administered after the surgical removal of the tumor. This reduces the risk of recurrence. Hormone therapy, but especially chemotherapy, are, however, harsh treatments. Chemotherapy has many side effects, such as hair loss, fatigue, and nausea. Suppose you would never relapse; then, of course, these treatments would be pointless. That is why researchers are trying to better predict the risk of recurrence. Suppose that risk is very small; then you would not have to undergo that harsh follow-up treatment.

Calculate the risk of relapse

It is possible to predict the risk of recurrence fairly accurately based on various molecular characteristics of certain breast cancers. These characteristics can be identified using a test known as a gene expression test. Gene expression tests have become increasingly common in recent years, including in Belgian breast clinics. Thanks to such tests, much less chemotherapy is now being administered than, say, ten years ago. The study presented in Chicago focuses on the use of such a test in patients with hormone-sensitive and HER2-negative breast cancer. 4,400 breast cancer patients were divided into two groups. One group received the standard treatment: surgery, chemotherapy, and hormone therapy. The second group was first tested using the gene expression test: those with a high risk of recurrence received the same series of treatments as the first group, but those with a low score did not receive chemotherapy and were given only hormone therapy. After five years, there was no difference in survival between the two groups: approximately 95% were still alive. Thanks to the test, researchers knew which patients had a low risk of recurrence and were able to spare them chemotherapy. The new test is promising, but it is not entirely new. On the contrary. In Belgium, a similar gene expression test has been used for several years for this same type of breast cancer: the Oncotype DX test. This shows that in about 70% of cases of hormone-sensitive, HER2-positive breast cancer, adjuvant therapy is unnecessary, as it does not improve life expectancy compared to not treating. Such predictive tests are very useful for further refining breast cancer treatment and initiating only those treatments that improve the prognosis. Through such a test, an individual breast cancer case acquires a sort of “identity.” It is a fine example of precision medicine. It is not only beneficial for the patient but also for the budget allocated to cancer therapies.

Would you like to read more about the available treatments for breast cancer? Take a look at this page on our website.

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