To investigate the long-term benefit of hormone-lowering treatment, researchers at Karolinska Institutet in Sweden followed 20 years of premenopausal women with breast cancer. The study, published in the Journal of Clinical Oncologyindicates that the treatment provides protection even after a longer period of time and that different patients seem to benefit from different hormonal treatments.
Hormonal treatments, also called endocrine treatments, have long been used after tumor surgery to reduce the risk of breast cancer cells spreading, but it’s not clear how long the treatment provides protection. Many cancers have a short-term risk of recurrence, usually within a few years. However, for patients with hormone-induced breast cancer, the risk of recurrence often extends over several decades.
About 80 percent of all people diagnosed with breast cancer have hormone-driven estrogen receptor-positive breast cancer, which means that estrogen stimulates cell division so that the tumor grows. Since many women are diagnosed with breast cancer at a relatively young age, it is very important to know the long-term effectiveness of treatment.
Building on the earlier STO-5 clinical trial, which was conducted between 1990 and 1997, Karolinska Institutet researchers have now investigated the long-term treatment benefit of hormone therapy in 584 premenopausal women with estrogen receptor-positive breast cancer. positive driven by hormones. The study also includes a control group that had not received any hormonal treatment.
We were able to see that after 20 years, the risk of developing distant metastatic disease, that is, spreading to other organs, had decreased among women who had received hormonal treatment with the drugs tamoxifen or goserelin or a combination of both, compared to those who had not received any hormonal treatment.”
Annelie Johansson, Study First Author, Postdoctoral Fellow, Department of Oncology-Pathology, Karolinska Institutet
In recent years, researchers have also analyzed tumors from patients in the earlier STO-5 study using modern technology. For example, they have investigated several breast cancer markers, such as the estrogen receptor and the progesterone receptor, as well as tumor gene expression using a genetic risk signature.
The signature measures the activity of 70 different genes, which are calculated into points of risk. This makes it possible to predict the future development of tumor cells at an early stage and thus categorize patients into low and high genomic risk, respectively.
“Tumors in patients with high genomic risk typically have a higher rate of cancer growth. So these patients are at earlier risk of relapse where more aggressive treatment is needed, such as with goserelin, which lowers estrogen levels.” quickly and effectively. Patients who have less aggressive disease may, on the other hand, have a long-term risk of recurrence. In these cases, tamoxifen appears to offer better protection,” says Annelie Johansson.
Although the study is relatively small, it highlights the importance of individualized treatments for hormone-induced breast cancer. For some patients, more aggressive treatment may be necessary for survival, while gentler treatment may suffice for others, reducing side effects and providing a better quality of life. However, more studies are needed before major changes in treatment recommendations can be implemented.
“To better understand long-term risk, treatment benefit, and age-related differences, we will now apply machine learning methods to image analysis of breast cancer tumors to further investigate differences between tumors.” says Linda Lindström, leader of the research group. in the same department and the corresponding author of the study.
The study was supported by grants from the Swedish Research Council, the Swedish Research Council for Health, Working Life and Welfare (FORTE), the Swedish Cancer Society, the Cancer Society in Stockholm, and the Gösta Milton Foundation.
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Magazine reference:
Johnson, A. et al. (2022). Twenty years of benefit of adjuvant goserelin and tamoxifen in premenopausal patients with breast cancer in a randomized controlled clinical trial. Journal of Clinical Oncology. doi.org/10.1200/JCO.21.02844.