Since it first hit the market in 1998, Viagra has remained the most remarkable medical innovation for sufferers of erectile dysfunction. When Pfizer scientists began researching sildenafil citrate – Viagra’s active ingredient – in the 1990s, they were actually testing it as a treatment for high blood pressure and angina. Only once they realized it could induce erections did they decide to market it as a treatment for ED.
Now, a recent study suggests there could be a brand new medical application for the little blue pill.
In a June paper published in Nature Communications, researchers in Sweden found that phosphodiesterase type 5 (PDE5) inhibitors – of which Viagra is one – may help prevent people with colorectal cancer (CRC) dying early of the disease. The study’s findings showed that PDE5 inhibitors – which are believed to have anti-tumor effects and reduce surgery-induced immunosuppression – are linked to a reduction in CRC-specific mortality risk and a reduced risk of metastasis.
“Specifically, post-operative use of PDE5 inhibitors has a strong anti-cancer effect,” the study found. “PDE5 inhibitors have the potential to be an adjuvant drug for patients with CRC to improve prognosis, especially those who have undergone open surgery.”
Using a national database, the study’s authors identified men diagnosed with CRC between 2005 and 2014, categorizing them according to whether they had or hadn’t taken PDE5 inhibitors during their illness. At a follow-up after four years, 10% of the group who had taken ED drugs died from the illness, compared with 17.5% of the group who hadn’t.
“After consideration of a range of clinical confounding factors, the relative risk of death caused by colorectal cancer was 18% lower among patients who used the drugs,” the study’s authors said in a press release. “The risk of metastases, especially distant metastases which is the main cause of death due to cancer, was also lower among patients who used PDE5 inhibitors.”
In the release, co-author Wuqing Huang said the research provides “the first-ever human-based evidence in terms of the anti-tumor effects of PDE5 inhibitors on colorectal cancer.”
But despite promising results, Jianguang Li, who also worked on the study, warned that research was still in its infancy. “The observed findings should be interpreted with caution as this is an observational study and the biological mechanisms need to be explored further,” he said.
According to Huang, the next step now is for researchers to confirm their findings in further tests. “Randomised clinical trials are needed to confirm our research findings before PDE5 inhibitors can be used as an adjuvant drug for men with colorectal cancer, as well as experiments that explore the underlying biological mechanisms,” she said.
Early research conducted in 2018 first indicated that PDE5 inhibitors could be useful in preventing early CRC-related deaths. A study conducted by August University’s Medical College of Georgia found that a small dose of Viagra taken every day “significantly reduces colorectal cancer risk in an animal model that is genetically predetermined to have a third leading cause of cancer death”.
The research showed that Viagra “cut in half the formation of polyps, an abnormal and often asymptomatic clump of cells on the lining of the intestines that may become cancer”.