Viagra may slow the spread of cancer, according to a new study

Viagra may do more than spice up your sex life and treat erectile dysfunction (ED), according to a new study published in Cancer Research. The research suggests that sildenafil, the active ingredient in Viagra, may slow the spread of cancer and improve overall survival rates. 

Better yet, survival rates were even higher when sildenafil was combined with statins, a common class of cholesterol-lowering medications.

Read on as we dig into what the study showed and what it might mean for the future of cancer and ED treatment.

Researchers from Israel’s Weizmann Institute of Science and Clait Health Services, along with those from the US National Cancer Institute (NCI), found that Viagra’s active ingredient, sildenafil, may slow the spread of cancer cells in the body by disrupting their ability to use cholesterol for transport. 

Taking sildenafil with statins, a common type of cholesterol medication, led to better overall cancer survival rates in men.

Confused? Let us explain. 

Sildenafil works by blocking an enzyme called phosphodiesterase type 5 (PDE5), which normally breaks down the chemical messenger cyclic guanosine monophosphate (cGMP). During sexual stimulation, higher levels of cGMP relax smooth muscle and wide blood vessels in the penis. This increases blood flow and makes it easier to get and maintain an erection.

However, according to the recent study, cGMP may do something else besides boosting blood flow: It may also bind to a protein that transports cholesterol throughout the body. 

So, sildenafil can lead to higher levels of cGMP, which can block the transport of cholesterol. This can leave the cancer cells with less cholesterol to use. 

Cholesterol may help cancer spread, a process known as metastasis. Some cancer cells use cholesterol to grow, invade nearby tissue, and travel from the original tumor to other parts of the body. But when cancer cells have less access to cholesterol, they may have a harder time hitching a ride and, ultimately, spreading. 

Enter: Statins

In the study, the cancer cells seemed to respond to less cholesterol by trying to make their own — and this is where statins came into play. 

Statins lower cholesterol levels by preventing cholesterol from being made in the body.  So, the combination of statins and sildenafil appeared to create a situation where there was less cholesterol that was overall available for cancer cells to use, and, thus, less ability for cancer cells to travel to other areas of the body.  

This could be why survival rates were highest among men taking both sildenafil and statins within six months of their cancer diagnosis. More frequent use of sildenafil (three or more times) during that period was also associated with higher survival rates.

“We have uncovered a new biological pathway that links a well-known signaling molecule to cholesterol regulation within cells, and shown how this pathway can be harnessed to interfere with the ability of cancer cells to form metastases,” Ayelet Erez, MD, PhD, who runs the lab used in the study, said in a press release.

All this said, it’s important to note that the findings were based on mouse cancer models, cultures of human cancer cells, and data collected over 20 years from five million patients at Clalit Health Services, Israel’s largest healthcare organization, which also contributed to the study.

Find your starter ED treatment

Get started

Nothing yet. This is one study, and though the results are promising, more research, including prospective human clinical trials, will need to be conducted before we can draw any conclusions.

It’s also worth noting that despite the large volume of data, there are some limitations to this study:

• Since sildenafil is primarily prescribed to men, the effects were also observed in men. We don’t know if sildenafil could have similar effects in women with cancer.

• The findings were based on overall survival rates from breast, lung, and colon cancer. (Yes, all genders can get breast cancer.) More research will need to be conducted to see if sildenafil has possible benefits for other cancers. 

• Sildenafil had little effect on primary tumor growth. Rather, it prevented the cancer from metastasizing, or spreading, into other areas of the body.

• Survival rates were highest among men who were taking both statins and sildenafil before their cancer diagnosis. Future studies may explore the effect of taking these medications together at later stages of the cancer’s progression to see if the medications are still helpful at a later time point

Still, the study’s discoveries are exciting because sildenafil and statins are widely available, commonly prescribed, and relatively affordable generic medications.

And this isn’t the first study to suggest sildenafil’s anticancer potential. Other preclinical studies have suggested it may have some anticancer effects for pancreatic, colon, breast, and lung cancer. So, if future research confirms these findings in large-scale human clinical trials, it’s possible we could see sildenafil being used as a complementary cancer treatment.

However, the findings are “still a long way from clinical use,” Yarden Ariav, PhD, who led the research from Dr. Erez’s lab, told The Jewish Chronicle. “We need much more research to figure out the right doses, timing, and whether it can be safely combined with chemotherapy or immunotherapy.”

So, it’s likely fair to say that it’ll be some time before we see the US Food and Drug Administration (FDA) expand Viagra’s current approvals as an ED medication. Speaking of which, it would be interesting to see if other PDE5 inhibitors — such as Cialis (tadalafil) — have similar cancer-fighting effects.

While this study has its limitations, the findings are still promising. We already have a good amount of scientific evidence and real-world support for Viagra as an effective ED treatment. So, Viagra as a cancer treatment? More research (and time) should tell. Until then, here’s a recap of the study’s findings, and what they may mean for the future:

• Recent research suggests sildenafil, the active ingredient in Viagra, may block cancer cells from using cholesterol to invade other areas of the body, limiting the spread of cancer.

• Overall cancer survival rates were highest among men who used sildenafil in combination with cholesterol-lowering medications called statins.

• The findings were based on mouse cancer models, cultures of human cancer cells, and patient data going back 20 years.

• More research is needed, including large-scale human clinical trials, to understand how sildenafil could help prevent the spread of cancer.

• Researchers will also need to explore whether sildenafil could benefit additional types of cancers than the ones that were studied, work in tandem with other treatments, and apply to women with cancer as well as men.