ED Medicine + Flu Shot May Enable Immune System To Limit Cancer Spreading After Surgery

A Canadian research team is suggesting that combining an influenza vaccine with erectile dysfunction medicines can enable the human immune system to eliminate cancer cells, left behind after surgery.

The lead researcher said, "We're really excited about this research because it suggests that two safe and relatively inexpensive therapies may be able to solve a big problem in cancer."

This mouse study shows that this unconventional strategy can reduce the spread of cancer by more than 90 percent in a mouse model.

The current, preclinical research investigated sildenafil (Viagra), tadalafil (Cialis) and an inactivated influenza vaccine (Agriflu) in a mouse model that mimics the spread of cancer (metastasis) after surgery.

This combination is now being evaluated in a world-first, human clinical trial.

The purpose of this study is to determine if giving Cialis for 5 days prior to surgery, on the day of surgery along with the influenza vaccine and Cialis 10 days after surgery will have an effect at the cell level for decreasing the chances of the spread of disease post surgery.

Dr. Rebecca Auer, surgical oncologist and head of cancer research at The Ottawa Hospital and associate professor at the University of Ottawa, said "We're now realizing that, tragically, surgery can also suppress the immune system in a way that makes it easier for any remaining cancer cells to persist and spread to other organs.”

“Our research suggests that combining erectile dysfunction drugs with the flu vaccine may be able to block this phenomenon and help prevent cancer from coming back after surgery."

The researchers evaluated these treatments by counting the number of metastases in mouse lungs. Normally, immune cells called natural killer (NK) cells play a major role in killing metastatic cancer cells. 

But surgery causes another kind of immune cell, called a myeloid-derived suppressor cell (MDSC), to block the NK cells.

Dr. Auer's team has found that erectile dysfunction drugs block these MDSCs, which allows the NK cells to do their job, fighting cancer. The flu vaccine further stimulates the NK cells.

They found an average of:

• 37 metastases with cancer cells alone
• 129 metastases with cancer cells and surgery
• 24 metastases with cancer cells, surgery and one of the erectile dysfunction drugs
• 11 metastases with cancer cells, surgery, one of the erectile dysfunction drugs and the flu vaccine.

"Cancer immunotherapy is a huge area of research right now, but we're still learning how best to use it in the time around surgery," said first author Dr. Lee-Hwa Tai, a former postdoctoral fellow in Dr. Auer's lab and now an assistant professor at the Université de Sherbrooke.

"This research is an important step forward that opens up many possibilities."

Dr. Auer noted that any change in a cancer patient’s medication therapy should be discussed with an oncologist, prior to any modification.

Acknowledgments and additional information: Dr. Auer's research is supported by generous donations to cancer research at The Ottawa Hospital. This study was also supported by the Canadian Cancer Society Research Institute and the Cancer Research Society. The trial is funded by Gateway for Cancer Research.

Dr. Auer is a member of BioCanRx, the Canadian Oncolytic Virus Consortium (funded by the Terry Fox Research Institute) and the Ontario Immuno-oncology Translational Research Initiative at the Ontario Institute for Cancer Research.

The Ottawa Health Science Network Research Ethics Board has approved the trial. See http://www.ohri.ca for more information about research at The Ottawa Hospital.