A new study led by Israeli researchers suggests that sildenafil, the active ingredient in Viagra, could one day play a role in slowing the spread of cancer by disrupting cancer cells' access to cholesterol, a key component needed for metastasis.
The research, published in the journal Cancer Research, was led by scientists at the Weizmann Institute of Science in collaboration with Clalit Health Services, the U.S. National Cancer Institute, and researchers and physicians from Clalit's Beilinson and Hasharon Hospitals.
Laboratory experiments revealed a previously unknown biological pathway through which sildenafil affects cholesterol regulation inside cells. According to the researchers, cancer cells rely heavily on cholesterol to detach from primary tumors and spread to other parts of the body. By limiting their access to cholesterol, sildenafil may make it more difficult for tumors to metastasize. The findings also suggest that combining sildenafil with cholesterol-lowering statins could further enhance this effect.
To support the laboratory findings, researchers analyzed more than 20 years of anonymized medical records from approximately five million Clalit members, including an observational study of 40,000 men diagnosed with cancer. They found that men who had taken sildenafil before their cancer diagnosis had better overall survival than those who had not. The strongest survival benefit was observed among patients who had used both sildenafil and statins before diagnosis.
Prof. Ayelet Erez, senior author of the study and Dean of the Faculty of Medicine at the Weizmann Institute of Science, said the research identifies "a previously unknown biological pathway that could be exploited to impair the ability of cancer cells to form metastases." She added that the findings demonstrate how cancer progression is influenced not only by genetic mutations but also by a patient's metabolic state and medications taken for unrelated conditions.
Dr. Samah Hayek, Senior Epidemiologist at the Clalit Research Institute and a co-author of the study, said the combination of laboratory research and real-world medical data strengthens the findings.
"This study bridges two worlds. The laboratory identified a promising biological mechanism, while Clalit's real-world data showed that the same signal may also be reflected in patient outcomes."
Despite the encouraging results, the researchers stressed that the study does not show Viagra treats cancer or should be used by cancer patients outside clinical trials. The analysis examined medication use before a cancer diagnosis and found an association with improved survival, but it did not test whether taking sildenafil after diagnosis improves outcomes.
"These findings are encouraging, but they do not mean cancer patients should start taking Viagra," Dr. Hayek emphasized, adding that randomized clinical trials will be needed to determine whether sildenafil could eventually become part of cancer treatment.
Viagra has been prescribed to more than 90 million men worldwide since its approval in 1998, while an estimated 200 million people currently take statins, making both medications among the most widely used prescription drugs globally.