BREAST cancer mortality is twice as likely in patients with high heterogeneity of the oestrogen receptor compared to those with low heterogeneity within the same tumour, according to researchers at the Karolinska Institutet, Solna, Sweden. The findings, which were independent of other known tumour markers, could provide the basis for new treatments for breast cancer.
Greater Long-Term Risk
In a cohort of 593 women diagnosed with post-menopausal oestrogen-receptor-positive breast cancer between 1976 and 1990, the team observed whether there was a greater long-term risk of death in those with high heterogeneity of the oestrogen receptor in their breast cancer tumour. Each patient had either been given tamoxifen or not treated with systemic therapy following surgery. It was found that, in a period up to 25-years after diagnosis, patients with high heterogeneity had twice the risk of death compared to those with low heterogeneity.
“Our study shows that patients with high intra-tumour heterogeneity of the oestrogen receptor were twice as likely to die up to 25 years after their diagnoses as compared to patients with low heterogeneity,” commented Dr Linda Lindström, Karolinska Institutet. “And this was independent of whether or not they’d received tamoxifen and of other known tumour markers.”
New Therapeutic Pathway
Notably, this higher risk also applied to Luminal A breast cancer patients, which is considered to have a good prognosis. The team believe that, if these findings are confirmed, they could be used as a new therapeutic pathway by researchers in the near future.
Oestrogen-Receptor-Positive Breast Cancer
Oestrogen-receptor-positive breast cancer is the most common form of the disease, and women who develop it have a remaining long-term risk of death. Survival is affected if the oestrogen receptor changes when a breast cancer tumour spreads, which could be caused by intra-tumour heterogeneity; this study provides additional evidence for this explanation.
James Coker, Reporter
For the source, and further information on the study, click here.