Can Viagra Help Protect Against Colon Cancer Death in Men?

That little, blue pill for impotence may have given your love life a boost, but it also might be protecting you from dying of colorectal cancer.
By on 08/18/2020 2:00 PM

Source: MedicineNet Health News

That little, blue pill for impotence may have given your love life a boost, but it also might be protecting you from dying of colorectal cancer.

Men who take Viagra (sildenafil) and have colorectal cancer – especially men who undergo colorectal cancer surgery – are more likely to survive longer without recurrence, according to a study published Monday in the journal Nature Communications. This is just the latest in investigations into PDE5 inhibitors' anti-tumor effects in colorectal cancer – PDE5 inhibitors is the class of drugs to which Viagra belongs.

“After adjustment for potential confounders, post-diagnostic use of PDE5 inhibitors was associated with a decreased risk of death due to colorectal cancer,” the study states. “The observed association was more pronounced in patients who underwent open surgery after diagnosis, especially those with dispensation after surgery.”

The Swedish meta-analysis of health records of people with colorectal cancer throughout the nation as recorded in multiple databases. A total of 12,465 male patients diagnosed with colorectal cancer at stage I, II, or III during the study period. Among them, a total of 1,136 patients used PDE5 inhibitors after the diagnosis.

Among people in the study populations who used PDE5 inhibitors after a colorectal cancer diagnosis, risk of death from colon cancer was 18% lower than in the rest of the study population. The effect was much stronger among men who had surgery for colorectal cancer and recovered.

The time window for the study was 4.25 years, so that means men on Viagra recovering from colorectal surgery were 18 percent more likely to be alive at the end of that period than those recovering from colorectal cancer surgery and not taking PDE5 inhibitors, the study states.

What Is Viagra and What Does It Do?

The main use for Viagra is to treat impotence or erectile dysfunction in men, according to the FDA.

Viagra is a PDE5 inhibitor, meaning it binds with the PDE5 enzyme used to break up crucial neurotransmitters, including the ones that govern blood flow in the penis.

When Viagra binds up the PDE5 enzyme, it can’t decompose the neurotransmitters that open and engorge penis blood vessels, thus creating the neurochemical conditions for an erection.

PDE5 inhibitors like Viagra are also used to treat pulmonary hypertension because of their action to help dilate blood vessels, according to FDA prescribing information.

How Can Viagra Help Colon Cancer Survival?

Researchers over the last 10 years have noticed that people with a high expression of the gene PDE5A, which makes the PDE5 enzyme, tended to have worse outcomes from colorectal cancer. It’s not clear why this is, but some researchers theorize PDE5, in addition to its duties in a healthy functioning body, tumor cells can hijack and recruit it.

After colon cancer surgery, especially open surgery as opposed to laparoscopic, many people have relapses. Part of the reason is because the stress of surgery on the body can improve the conditions for growing cancer cells. Surgery causes immune suppression, and other factors that make it easier for colon cancer to relapse, the study states.

According to the current hypothesis, if you knock out enough of the PDE5 enzyme, it’s like jamming the tumor assembly line, hindering the reproduction and spread of cancer cells.

"The results of our study suggest that the anti-cancer ability of PDE5 inhibitors might be related to regulating immunosuppressive effects,” study author Wuqing Huang told Medical and Life Sciences News. “However, randomized 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."

What Is the Current Treatment for Colon Cancer?

Colorectal cancer is the third most common cause of cancer in the U.S. in both men and women, writes MedicineNet author/editor . It affects over 135,000 people annually, representing 8% of all cancers. About 4.3% of people will be diagnosed with colon or rectum cancer at some point in their lives.

If further research establishes PDE5 inhibitors as a standard treatment for colon cancer, it would be an adjunct cancer treatment. That means it could help the other treatments along, not that Viagra is a wonder drug for killing tumors.

Surgery is the most common initial medical treatment for colorectal cancer Dr. Stöppler said. During surgery, the tumor, a small margin of the surrounding healthy intestine, and adjacent lymph nodes are removed. The surgeon then reconnects the healthy sections of the bowel, she said.

In patients with rectal cancer, the rectum sometimes is permanently removed if the cancer arises too low in the rectum. The surgeon then creates an opening (colostomy) on the abdominal wall through which solid waste from the colon is excreted. Specially trained nurses (enterostomal therapists) can help patients adjust to colostomies, and most patients with colostomies return to a normal lifestyle, Dr. Stöppler said.

For early bowel cancers, the recommended treatment is surgical removal. For most people with early stage colon cancer (stage I and most stage II), surgery alone is the only treatment required. Chemotherapy may be offered to some people with stage II cancers who have factors suggesting that their tumor may be at higher risk of recurrence.

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Colon Cancer: Symptoms, Signs, Screening, Stages See Slideshow

However, once a colon cancer has spread to local lymph nodes (stage III), the risk of the cancer returning remains high even if all visible evidence of the cancer has been removed by the surgeon. This is due to an increased likelihood that tiny cancer cells may have escaped prior to surgery and are too small to detect at that time by blood tests, scans or even direct examination. Their presence is deduced from higher risk of recurrence of the colon cancer at a later date (relapse), Dr. Stöppler said.

Medical cancer doctors (medical oncologists) recommend additional colon cancer treatments with chemotherapy in this setting to lower the risk of the cancer's return. Drugs used for chemotherapy enter the bloodstream and attack any colon cancer cells that were shed into the blood or lymphatic systems prior to the operation, attempting to kill them before they set up shop in other organs, Dr. Stöppler said.

There are several different options for adjuvant chemotherapy for the treatment of colon cancer. The treatments involve a combination of chemotherapy drugs given orally or into the veins. The treatments typically are given for a total of six months. It is important to meet with an oncologist who can explain adjuvant chemotherapy options as well as side effects to watch out for so that the right choice can be made for a patient as an individual Dr. Stöppler said.

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