Lead researcher, Mieke Van Hemelrijck, PhD, claims that the estimates for relative and absolute risk were modest. He states, “This is important from a public health perspective, since a large proportion of the population in many western countries suffers from hypertension.”
According to Per Hall, MD, PhD, medical oncologist at the Karolinska Institute, this research offers implications in the realm of intervention. He explains, “Primary prevention strategies developed by cardiologists have the potential to lower the risk of cancer. If we look for other things also, it would definitely improve overall survival.”
In other words, if oncologists could learn to think beyond cancer therapy and consider treating the whole person, including hypertension and cardiovascular disease, then there could be considerable benefits for patients.
This study is by far the largest of its kind, involving data analysis from nearly 290,000 men and 290,000 women. The data came from the Metabolic Syndrome and Cancer project, which includes people from Norway, Sweden, and Austria who had undergone regular health examinations from1972 to 2005.
After a median follow-up of 12 years, excluding the first year, cancer had been diagnosed in 22,184 men and 14,744 women. Of these 8724 men and 4525 women had died from cancer.
The rise in cancer incidence with increasing blood pressure was of statistical significance in men – specifically for oral, colorectal, lung, bladder, and kidney cancers, and melanoma and nonmelanoma forms of skin cancer. The overall risk of developing any cancer was increased by 29% among men in the group with highest level of blood pressure when compared to those with the lowest levels.
There was also a boost in cancer incidence in women, but it did not have the same level of statistical significance. An increase in incidence risk was observed for pancreas, liver, cervix, and endometrial cancer, and for melanoma.
Increasing blood pressure also increased a person’s risk of dying from cancer; this effect was significant in both genders. Men in the high level blood pressure group had a 49% increased risk for cancer death compared with those in the low level group. For women, this risk was increased by 29%.
According to Jan Willem Coebergh, MD, PhD, professor of cancer surveillance at the Eindhover Cancer Registry in the Netherlands, “this extensive population-based study on the role of concomitant hypertension shows it has a modest effect on the risk of certain cancers, expecially the kidney and colorectum, but it is probably a smaller effect than that caused by diabetes and various vascular conditions."