Study finds thyroid link to higher breast cancer risk

Posted on February 11, 2016 03:20 am

Experts writing in the European Journal of Endocrinology have said that hyperthyroid women were 11 per cent more likely to develop breast cancer, whereas those with hypothyroidism were 6 per cent less likely to develop the condition.”Our findings emphasise the importance of raising awareness of breast cancer in women with hyperthyroidism, and further our understanding of this potential risk,” said lead author Dr Mette Sogaard from Aarhus University Hospital in Denmark.”In vitro experiments show that sex hormones such as oestrogen play an important role in the proliferation of breast-cancer cells.”High levels of thyroid hormone levels can have oestrogen-like effects, which may explain why hyperthyroidism is associated with higher risk of breast cancer.”Experts in Denmark used nationwide registries to identify women with over and under-active thyroids between 1978 and 2013.They then estimated their risk of breast cancer compared with the expected risk in the general population.Of the data pertaining to more than four million women, they identified 61,873 women diagnosed with hypothyroidism and 80,343 women diagnosed with hyperthyroidism.Women with an overactive thyroid have an increased risk of breast cancer, a new study suggests.Hyperthyroidism is a relatively common condition which occurs when there is too much thyroid hormone in the body.Women with an underactive thyroid gland, also known as hypothyroidism, carry a lower risk than the general population, the study concluded.

According to a review published in the February issue of Cancer Epidemiology, Biomarkers & Prevention, the likelihood of developing breast or thyroid cancer as a secondary malignancy is increased following diagnosis of the other cancer.Sarah M. Nielsen, from the University of Chicago, and colleagues conducted a systematic review and meta-analysis of the literature to identify all publications examining the incidence of breast cancer as a secondary malignancy following thyroid cancer diagnosis, or thyroid cancer following breast cancer diagnosis. Nineteen unique cohorts of breast cancer patients and 18 of thyroid cancer patients were identified.Data were analyzed for 956,672 breast cancer patients and 611 secondary thyroid cancers, and for 44,879 thyroid cancer patients and 5,791 secondary breast cancers. The researchers found that the risk of thyroid cancer as a secondary malignancy following breast cancer was increased at odds ratio, 1.55. Furthermore, the risk of breast cancer following thyroid cancer was increased at odds ratio, 1.18.”The importance of the relationship between breast and thyroid cancer will continue to become evident as the incidence of thyroid cancers continues to rise and the treatments for both cancers continue to improve,” the authors write.

Two days ago, researchers from the Institute of Cancer Research, London, and the University of Manchester published their discovery that a receptor protein called EPHA2 is responsible for whether or not tumor cells break out of vessels. A reactor protein has been pinned down which it is hoped will help prevent breast cancer from spreading, according to their new study. The researchers believe it could be possible to successfully manipulate the protein in patients.Building on the knowledge that tumor cells spread by entering the blood stream and latching onto the inner walls of blood vessels.They found that when cancer cells interact with the walls of blood vessels, EPHA2 is activated and tumor cells remains inside the blood vessels. However, when EPHA2 is inactive, the tumor cells can push out and spread.”This is important research that teaches us more about how breast cancer cells move. Research like this is vital to help our understanding of how cancer spreads, and how to stop this from happening. More research is needed before this will benefit patients but it’s a jump in the right direction,” said Cancer Research UK’s senior science manager, Nell Barrie.The researchers believe the finding could inspire a way to activate EPHA2 so that tumor cells can’t spread.“The next step is to figure out how to keep this receptor switched on, so the tumor cells cannot leave the blood vessels, stopping breast cancer spreading and making the disease easier to treat successfully,” said Dr. Claus Jorgensen, who led the research.

Contador Harrison