Breast cancer is the second most prevalent type of cancer worldwide and the most common cancer in women. According to the Cancer Association of South Africa (CANSA), up to one in 26 South African women will be diagnosed with breast cancer in her lifetime. For many of these women, chemotherapy is the mainstay of treatment – or, at least, it has been until now. A recent study presented in June this year and published in The New England Journal of Medicine suggests that about 70% of patients diagnosed with the most common form of breast cancer may be able to safely forego this aggressive treatment option.
It’s all in the genes
Usually when determining a treatment plan for a breast cancer patient, doctors use a 21-gene test called TAILORx. By testing the patient’s cancer biopsy sample, healthcare professionals are able to assign a recurrence score from zero to 100 – the higher the score, the greater the risk of the cancer reappearing in distant organs. This also means that the higher the score, the more essential the need for chemotherapy as it can greatly reduce the chances of recurrence. According to previous studies, a score below 10 typically means the patient does not need to have chemo while a score above 25 indicates that this treatment would be beneficial.
But what about those women – the majority of breast cancer cases – who fall between 10 and 25 on the scale? Up until now, there had often been uncertainty as to whether the pros of chemo – which is toxic to many cells of the body, not just cancer cells – outweighed the cons in intermediate-range cases. The new study, which was presented at the 2018 meeting of the American Society of Clinical Oncology, focuses on exactly these cases. Using the data of 10 273 women who all had hormone-receptor positive, HER-2 negative cancer that had not spread to lymph nodes – the most common type of breast cancer – the researchers’ main focus was the almost 70% of women with TAILORx results from 11 to 25.
By examining the outcomes (such as being cancer free, having cancer recur locally or elsewhere in the body and overall survival) of patients either assigned to eceive chemotherapy followed by hormonal therapy or assigned to receive hormone therapy alone, the team of researchers made their ground-breaking observation: there was no significant difference between the group receiving chemo and those who weren’t in women with gene tests between 11 and 25.
“The study should have a huge impact on doctors and patients,” said oncologist and co-author Dr Kathy Albain. “Its findings will greatly expand the number of patients who can forego chemotherapy without compromising their outcomes. We are de-escalating toxic therapy.”
The importance of screening
Breast cancer outcomes are best when the disease is detected early. “Research has shown that a regular breast self-examination (BSE) plays an important role in discovering breast cancer, compared to finding a breast lump by chance.” says CANSA. They advise performing a BSE once a month, at the same time of day, following the menstrual cycle.
Why chemo works – and hurts
Chemotherapy targets cells that grow and divide rapidly – one of the hallmarks of cancer. However, some healthy cells of the body behave in this way too. With no way for the chemotherapy to tell the difference between a healthy and unhealthy cell, skin, hair, gastrointestinal, reproductive and bone marrow cells all come into its firing line, resulting in many of the unpleasant side effects associated with this treatment. These can include hair loss, fertility issues, fatigue, digestive issues, anaemia, and easy bruising and bleeding. Treatment with chemotherapy is a fine balancing act between killing the malignant cells and sparing the healthy ones.
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