Many women won’t need chemotherapy when guided by a diagnostic test: US study

More women with the most common form of early stage breast cancer may not need chemotherapy and may instead rely on hormone therapies, according to a landmark study.

The findings in the study were based on a 21-tumor gene expression test which would also inform treatment decisions in real life.

BCAC says anecdotally there has been a perceived reluctance to use the Oncotype test in New Zealand because of concerns regarding its ability to accurately predict the risk of breast cancer recurrence and its cost.  We are very pleased that these results will allay some of those concerns.

Chemotherapy is wonderful when patients need it, but we recognise that when it is not needed then it is beneficial to avoid it.  It is those with high risk of recurrence who will continue to gain the greatest benefit from chemotherapy.

It is also important to understand that the test looks for abnormality within the cancer cells which will cause growth and spread, not genes in normal body cells and should not be confused with tests that look for an inherited faulty gene that increases a person’s risk of getting cancer in the first place.

This study focussed on the group with intermediate risk who we now understand also may not benefit from chemotherapy relying instead on hormone therapies.  Another finding that is important to emphasise is that women under 50 will continue to gain benefit from chemotherapy. To gain greater clarity people should speak with their oncologist.

The findings from the study, a clinical trial involving 10,273 patients, were presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago in June. The full name of the test is Oncotype DX® Breast Recurrence Score.

ASCO Expert Harold Burstein, MD, PhD, FASCO said the findings mean that “thousands of women will be able to avoid chemotherapy, with all of its side effects, while still achieving excellent long-term outcomes”.

A news release from the annual meeting says the clinical trial shows that most women with hormone receptor-positive, HER2-negative, axillary node-negative early-stage breast cancer and a mid-range score on the 21-tumor gene expression test do not need chemotherapy after surgery.

The study, known as TAILORx, found no improvement in disease-free survival when chemotherapy was added to hormone therapy in this group, which accounts for about two-thirds of women who participated in the trial.

The study was one of four presented at the conference that were deemed to have the greatest potential to impact patient care. It is the largest breast cancer treatment trial ever conducted, according to the authors.

“Half of all breast cancers are hormone receptor-positive, HER2-negative, and axillary node-negative. Our study shows that chemotherapy may be avoided in about 70 percent of these women when its use is guided by the test, thus limiting chemotherapy to the 30 percent who we can predict will benefit from it,” said lead study author Joseph A. Sparano, MD, Associate Director for Clinical Research at the Albert Einstein Cancer Center and Montefiore Health System in New York, and Vice-Chair of the ECOG-ACRIN Cancer Research Group.

More about the study

The 21-gene expression test is performed on a tumour biopsy sample. In the trial, women with a low score (0-10) typically receive only hormone therapy and those with a high score (26-100) receive hormone therapy and chemotherapy.

According to the authors, the findings suggest that chemotherapy may be spared in:

  • all women older than 50 years with hormone-receptor positive, HER2-negative, node-negative breast cancer and a Recurrence Score of 0 to 25 (about 85% of women with breast cancer in this age group)
  • all women 50 years or younger with hormone-receptor positive, HER2-negative, node-negative breast cancer and a Recurrence Score of 0 to 15 (about 40% of women with breast cancer in this age group)

The study received funding primarily from the following US-based organisations: National Cancer Institute, part of the National Institutes of Health. Additional support was provided by the Breast Cancer Research Foundation, Komen Foundation, and the US Postal Service Breast Cancer Stamp. The ECOG-ACRIN Cancer Research Group designed and conducted the study.

More comment from BCAC:

BCAC also comments that all major practice guidelines in the UK endorse some of these tests. The National Institute of Health and Care Excellence (NICE) guidelines only endorse OncotypeDX which is funded in England and Wales although an announcement was made in February this year that this is under review.

There are other similar tests such as PAM50-based Prosigna Risk of Recurrence Score (ROR), Breast Cancer Index (BCI) and Endopredict (EPclin) which all look at expression levels of multiple genes related to breast cancer to predict risk of recurrence. The US Food and Drug Administration (FDA) has approved ROR, and the European Society for Medical Oncology has approved Oncotype, ROR and EPclin. 

In New Zealand and Australia patients are generally required to fund these tests themselves.

Given potential savings achievable through a reduction in chemotherapy use, BCAC would like to see both private insurers and PHARMAC funding these tests in the future.

CREDIT:  This article is based on a news release from the American Society of Clinical Oncology (ASCO) annual meeting, and BCAC comment.

10 June 2018

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