A new online tool may predict the risk of breast cancer returning and spreading to other areas of the body.
The prognostic tool, CTS5 (Clinical Treatment Score post-5-years), may be used to decide which patients are at high enough risk of their cancer returning after the standard five years of endocrine (hormone) therapy to benefit from continuation of treatment.
The calculator was developed by researchers at the Royal Marsden NHS Foundation Trust and at Queen Mary, University of London. It can also be used to predict which patients are at low risk of recurrence. They would avoid undergoing further therapy and its potential adverse side-effects.
Over the last three decades, there has been a major increase in the rate of invasive breast cancer in western countries. 85% of patients are now diagnosed as oestrogen receptor (ER) positive, which means that the cancer grows in response to the hormone, oestrogen.
Almost all of these patients are prescribed five years of hormone therapy, after standard treatment (surgery, chemotherapy, and/or radiation therapy), to lower the risk of the cancer returning. However, hormone therapy can have significant side-effects, including weakness of bone tissue and exacerbation of menopausal symptoms.
Oncologists have to decide, after five years of hormone treatment, whether extending this therapy is worthwhile and appropriate.
The team developed CTS5 after reviewing data from two previous studies.
Together, these provided information on 11,446 postmenopausal women with ER-positive breast cancer, who had received five years of hormone therapy (tamoxifen, anastrozole, or letrozole).
CTS5 was shown to accurately separate women into groups of low, intermediate, or high risk of developing a late, distant recurrence of breast cancer, after five years of hormone therapy.
The test identified 42% of women who were at sufficiently low risk that extending hormone therapy would have been of little value.
Co-lead researcher, Mitch Dowsett, head of the Royal Marsden Ralph Lauren Centre for Breast Cancer Research and professor of biochemical endocrinology at the Institute of Cancer Research (ICR), said the calculator could prevent breast cancer patients from having unnecessary extended treatment.
Prof Dowsett added: “Clinicians require expertise, and the best tools, to help them make crucial decisions on treatment for patients, decisions that can make a difference to patients’ quality of life. This tool uses information that is already gathered in all patients, so could be easily used across the UK, and globally at other centres.
Co-lead researcher, Professor Jack Cuzick, from Queen Mary, University of London, said: “Hormone-sensitive breast cancer is one of the few cancers where late recurrence is common, and predicting who is at high risk is particularly important, so that they can continue hormone treatment. While our ability to predict this type of cancer is highly likely to improve in the future, we’re providing a simple tool, which is available now.”