An international clinical trial with more than 4,400 participants showed that many people with breast cancer They can do without chemotherapy without increasing the risk of the disease returning. The results of the study OPTIMAled by the University College Londonwere presented at the American Society of Clinical Oncology (ASCO) meeting in Chicago and could transform the standard of care for thousands of patients each year.
The study focused on people aged 40 or older with hormone-sensitive breast cancer —the most common type, which responds to hormones such as estrogen—that had already reached nearby lymph nodes. For these patients, the usual protocol includes chemotherapy followed by several years of hormonal therapy. The problem that OPTIMA tried to solve is that many of them receive the chemotherapy side effects without obtaining any clear benefit, as detailed by University College London in a statement.
To identify who really needs that treatment, the trial incorporated a genomic test called prosigndeveloped by the company Veracyte. The test analyzes the activity of genes involved in tumor growth from a tissue sample, either removed during surgery or through a needle biopsy. A key advantage is that it can be processed in laboratories in the British public health system without special equipment.
Trial participants were randomly assigned to two groups. One group received the standard treatment: chemotherapy plus hormone therapy. The other group was evaluated with the Prosigna test: those who obtained a high score – above 60 – received both treatments, while those who had a low score – equal to or less than 60 – received only hormonal therapy.
The numbers that support the protocol change
Of the 4.429 personas who participated in the trial, 68 percent obtained a low score on the Prosigna test. For this group, five-year outcomes were virtually identical between those who received chemotherapy and those who did not. 94.8 percent of the patients who did receive it were alive and without cancer recurrence; in the group that only received hormone therapy, that percentage was 93.6 percent.
Additional statistical analysis indicated that, at most, only 2 percent of low-scoring patients derive any real benefit from chemotherapy. The difference in results between the two groups was well below the 3 percent threshold that researchers and patients had defined as the acceptable limit when designing the study.
The teacher Rob Steinprincipal investigator of the trial and Professor of Breast Oncology at the UCL Cancer Institute, said: «OPTIMA addresses a long-standing challenge in breast cancer treatment: identifying who really benefits from chemotherapy and who does not. Our results show that many patients can safely avoid it without compromising their outcomes.»
Researchers estimate that more than 5,000 patients per year in the UK public health system could avoid chemotherapy thanks to this trial. The complete trial data will be evaluated by the National Institute for Health and Care Excellence (NICE)the body that regulates what treatments the NHS funds, to decide whether to expand access to the Prosigna test.
Unlike previous studies, OPTIMA included both premenopausal women and patients with more extensive disease, including more than three nodes affected. In both cases the results were similar. The researchers noted that premenopausal women received hormone therapy that temporarily suppresses ovarian function, which would explain why chemotherapy offered no additional benefit in that group.
The teacher Iain MacPhersonco-principal investigator and lecturer at the University of Glasgow, warned: «OPTIMA provides robust and practice-changing evidence: we can safely reduce the use of chemotherapy for many patients with hormone-sensitive breast cancer. The potential impact, for both patients and health systems, is substantial.»
One of the trial participants was Karen Bonham64 years old, diagnosed in 2017 after a routine mammogram. With a tumor larger than 5 centimeters and two lymph nodes involved, chemotherapy was the planned treatment. Thanks to the Prosigna test, which showed a low score, Karen was assigned to the hormone therapy group. «How to describe the initial feeling? Immense relief. Like Christmas? Certainly a mix of both,» he said. Almost nine years after his diagnosis, he completed eight years of active treatment and returned to his normal life.
