New Study to Examine Link Between Blood Pressure Meds and Breast Cancer

Curtin University researchers are examining possible links between blood pressure medication and breast cancer Illustration - Shutterstock

A new study conducted by Curtin University will examine the link between long-term use of common blood pressure pills and the risks of getting breast cancer.

The lead researcher of the study Prof. Rachael Moorin said there were global concerns that the drugs could be causing an increase in breast cancer for women.

“The use of calcium channel blockers may increase the risk of cancer because of their role in changing intracellular calcium levels, and breast tissue may be particularly susceptible to the adverse effects of changing intracellular calcium due to its secretary role.”

Calcium channel blockers (CCBs) lower blood pressure by stopping calcium ions from entering smooth and heart muscle cells to induce contractions in the heart and arteries. Since muscle contractions are largely dependent on an influx of calcium, blockage results in relaxation, especially in the arteries.

However, calcium signalling is also a critical regulator for processes important in cancer. Cancerous cells are often found to have more calcium channels present on their cell surface compared to normal cells.

Changes in calcium influx and signalling are often observed in breast cancer cells; blockers for specific types of calcium channels are found to be more potent at stopping breast cancer proliferation than normal breast cells, and researchers have observed some calcium channels to be overexpressed in certain forms of breast cancer.

Whilst an association between calcium signalling and breast cancer exists, research on the link between CCBs and breast cancer has been mixed.

The main literature that has brought attention to the possible relationship between CCB and breast cancer was published in 2013 by Fred Hutchinson Cancer Research Center, where researchers observed a positive relationship between post-menopausal women taking CCBs and two invasive forms of breast cancer.

However, a later study in 2014 debunked findings in the study, finding no evidence of a link between the treatment and the disease.

Prof. Moorin said the study would have significant implications for Australian women.

“The incidence of breast cancer is rising with 19,535 new cases (pdf) diagnosed in Australia in 2019, a 19 per cent increase compared with 2013. Breast cancer is second only to lung cancer as the most common cause of death from cancer in Australian women,” she said.

The team will examine three previous Australian and Dutch longitudinal cohorts and expects to take three years to complete the study.

“With an estimated 48 women diagnosed each day, breast cancer was the most commonly diagnosed cancer in Australia in 2019 and the most common in women, with one in seven Australian women diagnosed with breast cancer by the age of 85,” Moorin said.

The study will be given $1 million in funding from the federal government’s National Health and Medical Research Council (NHMRC) Clinical Trials and Cohort Studies Grants and will examine the Australian Longitudinal Study on Women’s Health, the 45 and Up Study data from the Department of Human Services database and The Rotterdam Study from The Netherlands.

“Australia continues to be at the forefront of medical research, and these projects have the potential to increase not only our understanding of diseases but to also revolutionise their treatment,” said Australian Health Minister Greg Hunt on May 18.