No relief yet for brutal oral cancer pain, but cannabinoids may offer some hope

May 3, 2014

Science Daily/American Pain Society

Many cancer patients endure severe pain and, by far, one of the most excruciating pain conditions is caused by oral cancer, for which even the strongest available pain medications are largely ineffective. One of the nation's leading oral cancer treating clinicians, speaking at the American Pain Society's annual meeting, said he believes that while prospects for major treatment advances remain bleak, a new cannabinoid-based medication may have some promise for providing meaningful pain relief.

Brian Schmidt, DDS, MD, PhD, professor, New York University College of Dentistry and School of Medicine, delivered the Global Year Against Pain Lecture and reported that today, more than 100 years since President Ulysses S. Grant died from oral cancer, there is only modest improvement in patient survival. Grant is the only American president to die from cancer.

"Oral cancer is one of the most painful and debilitating of all malignancies," said Schmidt, " and opioids, the strongest pain medications we have, are an imperfect solution. They become dramatically less effective as tolerance to these drugs develops."

Now considered to be the fastest increasing cancer in the United States, oral and oropharyngeal malignancies usually begin in the tongue. Human papillomavirus transmitted through oral sex, tobacco use and excessive alcohol consumption are the leading causes of this increase in oropharyngeal cancer. In the United States, some 43,000 new cases of oral cancer are diagnosed every year and the disease is more widespread worldwide with 640,000 new cases a year.

Schmidt said oral cancer patients often undergo multiple surgeries as tumors recur and also are treated with radiation and chemotherapy. The disease is difficult to diagnose at early stages and spreads quickly, leaving patients in gruesome pain and unable to speak or swallow. "Our inability to effectively treat oral cancer stems from lack of knowledge. We know that cancer pain is caused by a unique biological mechanism, but more research is needed to develop medications that are effective in treating oral cancer pain," Schmidt said.

"The only way we can hope to reduce the devastating impact of oral cancer pain is to fund more research to help those who suffer or will suffer from this ruthless disease," Schmidt told the APS audience. He added that half of oral cancer patients do not survive five years after diagnosis.

Schmidt noted that perhaps some good news is on the horizon, as clinical trials proceed for a drug produced directly from a marijuana plants (Sativex). It is administered as an oral spray and shows promise for treating cancer pain. The drug is available in Canada and Europe for treating spasticity from multiple sclerosis and is in Phase 3 clinical trials in the United States for treatment of cancer pain. Schmidt is a clinical investigator for Sativex trials.

"While it's too early to conclude the cannabinoid medication will provide effective cancer pain relief, we do know that humans possess numerous cannabinoid receptors in the brain and body which regulate a significant amount of human physiology. So, there is hope that cannabinoid-based medications can become effective pain relievers for cancer patients."

https://www.sciencedaily.com/releases/2014/05/140503141201.htm