Blood Hormone Levels Key to Identifying Post-Menopausal Women who Benefit from Breast Cancer Medication, New Study Finds
Research led by Queen Mary University of London’s Wolfson Institute of Population Health has revealed that hormone levels, measured through blood tests, are a crucial factor in determining which post-menopausal women will benefit from recently licensed medication for the prevention of breast cancer. The study, published in Lancet Oncology, has significant implications for the targeting of preventive therapies and could improve the effectiveness of treatment for those at high risk of breast cancer.
The National Institute of Clinical Care and Excellence (NICE) recommends the use of aromatase inhibitors, such as anastrozole, as an option for preventive therapy in post-menopausal women who are at high risk of developing breast cancer. These inhibitors work by stopping the production of estrogen, which is known to contribute to the development of breast cancer. However, the study led by Professor Jack Cuzick and his team suggests that hormone levels can help identify which women will benefit the most from these drugs.
Breast cancer is a prevalent disease, with 1 in 7 women in the UK being diagnosed at some point in their lives. Post-menopausal women with higher levels of the hormone estrogen in their bloodstream are particularly at risk. Aromatase inhibitors like anastrozole provide a significant reduction in the risk of developing the estrogen-receptor positive breast cancer that many post-menopausal women face. However, by utilizing hormone level measurements, it may be possible to tailor medications even further to those individuals who will benefit the most.
The international research team, composed of experts from the UK, Australia, Finland, Germany, Italy, and the USA, conducted a comprehensive analysis of the data from the IBIS-II prevention trial. This trial involved post-menopausal women at high risk of breast cancer and was carried out between 2003 and 2012. By assessing hormone levels in the blood, specifically estrogen, the researchers identified a clear correlation between hormone levels and the effectiveness of the preventive effects of an aromatase inhibitor like anastrozole.
The case-control study included 212 women, out of which 72 were breast cancer cases and 140 were controls. In the placebo group, there was a noticeable trend of increasing risk with higher hormone levels. However, this trend was not observed in the group taking anastrozole. Remarkably, those women in the bottom 25% of estrogen levels experienced a much smaller reduction in cancer risk compared to those who had higher levels of the hormone. These findings indicate that utilizing inexpensive blood tests to measure hormone levels could significantly enhance the selection process for preventive therapy using aromatase inhibitors.
Professor Jack Cuzick emphasized the potential of these results, stating, These results are very exciting and can refine how we choose preventive medication for post-menopausal women at high risk of breast cancer. He continued, A simple blood hormone test could improve the benefit of anastrozole if we use it to select the patients best suited to take it. The ability to personalize medication based on hormone levels would optimize the balance between managing cancer risk and minimizing side effects.
Dr. David Crosby, head of prevention and early detection at Cancer Research UK, hailed the findings as a significant step towards targeted treatments. This research gives us some clues about which women would benefit most from the drug, while identifying women who won’t benefit and can be spared unnecessary side effects, he said. Cancer Research UK played a vital role in the development of aromatase inhibitors, and further investigations building on this study’s results are crucial for understanding which individuals are likely to benefit the most.
The study’s lead author, Professor Cuzick, is a renowned researcher in breast cancer prevention and treatment, having published over 500 peer-reviewed papers. His previous work has contributed to the use of tamoxifen as a prophylactic treatment for women at risk of breast cancer. Additionally, he led the IBIS-II trial, which examined the efficacy of anastrozole as an aromatase inhibitor in breast cancer prevention. In recognition of his contributions, Professor Cuzick will be presented with the William L. McGuire Memorial Lecture Award at the 2023 San Antonio Breast Cancer Symposium (SABCS).
The study was funded by Cancer Research UK, the National Health and Medical Research Council of Australia, the Breast Cancer Research Foundation, and the Royal Marsden Cancer Charity. These organizations have played pivotal roles in advancing breast cancer research and improving patient outcomes.
This groundbreaking research has the potential to transform breast cancer prevention by enabling the targeted use of aromatase inhibitors based on hormone levels. By identifying the individuals who will derive the greatest benefit from these medications, healthcare professionals can optimize treatment plans and minimize unnecessary side effects. With breast cancer affecting countless women globally each year, these findings offer hope for a more personalized and effective approach to prevention.
