One in three breast cancer patients may experience changes in a key tumour marker during treatment before surgery, potentially affecting the type of therapy they should receive afterwards, according to a new Polish study.
Researchers found that levels of the HER2 protein—a crucial target for some of the most effective breast cancer drugs—changed in around one-third of women undergoing preoperative (neoadjuvant) treatment. The findings suggest patients could benefit from having their tumours retested after treatment to help determine the most appropriate follow-up care.
The study, published in Therapeutic Advances in Medical Oncology, analysed 736 breast cancer patients treated by an interdisciplinary team at Poland's National Research Institute of Oncology, working with a biostatistician from the Warsaw University of Life Sciences (WULS-SGGW).
Breast cancer is not a single disease but a group of cancers with different biological characteristics, clinical outcomes and responses to treatment. One of the most important markers is the human epidermal growth factor receptor 2 (HER2), a protein found in high levels on the surface of cancer cells in some patients.
HER2-positive breast cancers tend to grow and spread more aggressively, but they can also be treated with drugs specifically designed to target the protein. Identifying whether a tumour is HER2-positive is therefore essential when selecting the most effective treatment.
The researchers found that HER2 status can change during neoadjuvant therapy, which is given before surgery to shrink tumours and improve treatment outcomes. The changes occurred between the initial biopsy taken before treatment and the examination of the remaining tumour after surgery.
Lead author Dr Katarzyna Pogoda, a clinical oncologist at the Department of Breast Cancer and Reconstructive Surgery at the National Research Institute of Oncology, said the most common change was a reduction in HER2 expression, while the appearance of a newly HER2-positive tumour was rare.
"The study results indicate that reassessing HER2 in residual disease may be important for selecting further postoperative treatment, and that it supports the development of more personalized breast cancer therapy," she said in a press release.
Pogoda noted that HER2 expression in residual disease is not always routinely reassessed after neoadjuvant treatment. However, the findings suggest that repeat testing could have significant clinical value and should be considered when planning further treatment. (PAP)
jjj/ bar/
tr. RL
