The following article features in Issue One of the ST BREAST magazine.
Not every woman diagnosed with breast cancer will need chemotherapy. Many in fact, can be safely treated with hormone therapy alone.
Associate Professor Nicole McCarthy from the ICON Cancer Centre in Brisbane says cutting-edge genomic tests like the Oncotype DX breast cancer assay can now provide women and their doctors with extra information about their breast cancer, as well as the likely benefit of chemotherapy.
“There is great relief when a woman is told she can be treated with hormone therapy alone,” Associate Professor McCarthy says.
“If you don’t need chemotherapy, it is a huge bonus. Women can keep working and living their lives, and not worry about the side effects associated with chemotherapy.
“Chemotherapy can impact cognitive function and general energy levels.
“Younger women may become menopausal quite abruptly as a result of chemotherapy. The side effects of this can be significant and debilitating. If it is safe to avoid chemotherapy, then that is far preferable .”
Associate Professor McCarthy admits many Australian women have probably been unnecessarily treated with chemotherapy as a safeguard to reduce their risk of breast cancer recurrence, in the absence of this specific information.
“Without the specific information provided by genomic tests, many clinicians will err on the side of caution,” she says.
“In Australia it is a cost issue. In many other developed countries, genomic testing is part of the standard of care and is used to help guide treatment decisions. Here, women can pay thousands of dollars for a test and for many, this cost is not manageable.
“I always tell eligible women about the availability of genomic testing, because some women will lose that amount in lost income just by missing work for treatment.”
We asked Associate Professor McCarthy to explain genomic testing – how it works and who is eligible.
What is genomic testing?
A genomic test involves taking a sample of a patient’s breast tumour and screening it for the presence of specific genes, providing information about the likelihood of how that breast cancer is going to grow and spread.
Should all breast cancer patients have a genomic test?
Genomic tests are most useful for patients whose cancers are hormone-receptor positive (HR+) and HER2-negative and whose cancer has not spread to lymph nodes, or involves only 1-3 nodes. For clinicians, it provides extra information and may be particularly beneficial for those patients who we think have an intermediate risk of recurrence, based on standard pathology tests. In these cases, a genomic test can help to confirm a decision on whether chemotherapy is necessary.
If we are sitting on the fence in terms of a decision regarding chemotherapy and a test comes back that puts the cancer in a low risk category, you feel much more comfortable with the decision to not recommend chemotherapy.
Is it really safe to avoid chemotherapy?
There is lots of clinical trial data that suggests that low-grade, node-negative, strongly hormone responsive cancers have a very good prognosis and that hormone therapy alone is enough.
Having used these tests for 7-8 years now, I have a growing confidence, because I have long-term follow up with some of my patients who have not had chemotherapy based on the advice of genomic tests, and who have done well.
While no test is perfect, genomic testing does provide us with additional information above and beyond what the standard pathology report tells us. There are a number of genomic tests available, but the strongest clinical data is with the Oncotype DX breast cancer assay.
What’s the case for avoiding chemotherapy?
There are all the usual reasons, including the physical side effects and the impact on family life.
While many women will still work when they are having chemotherapy, most women will not be able to maintain the same level of work during treatment. In fact, many women will not be able to maintain their level of function after chemotherapy, or it can take many months to recover.
Many women never go back to the work they were doing before chemotherapy.
Do some women doubt the accuracy of genomic testing and decide to pursue chemotherapy anyway?
I have only had one woman who has not followed the result recommendations. I tell women, ‘Don’t do the test if you are not going to be confident in the results. You don’t want to spend $5000 on a test if you aren’t going to follow its recommendation.
If a woman is particularly anxious and could not possibly forego chemotherapy because she wants to throw every treatment possible at her cancer, then I would say don’t ‘do the test’. A woman must be comfortable following the result.
I know of one woman who was desperate to avoid chemotherapy and had the test done. It came back and showed that she had a high risk of recurrence. She is now having chemotherapy and is very accepting of her treatment, because she recognises it was the right way to proceed.”
Associate Professor Nicole McCarthy