Cannabinoids May Provide Pain Relief in Oral Cancer

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Cannabinoids have been shown to combat cancer pain and proliferation in a mouse model.
Cannabinoids have been shown to combat cancer pain and proliferation in a mouse model.

New refinements and developments in the medical marijuana field may soon be benefiting patients with oral cancer. Oral and oropharyngeal malignancies are associated with significant pain conditions and clinicians have had only limited success with opioids and the most powerful pain medication combinations. Now, researchers are hoping that a form of synthetic marijuana may be able to help reduce morbidity rates in patients with oral cancer.   

A clinical trial is underway using an oral spray called Sativex, which is simply sprayed on the inside of the cheeks. “The company didn't want to use it for oral cancer because they were concerned it might cause mucosal irritation,” said Brian Schmidt, MD, DDS, PhD, a professor at New York University College of Dentistry and School of Medicine, New York, NY. “We don't know the results of the trial, but the initial results for it look very promising.”

Cannabinoid receptors have been shown to exist in brain cells and nerve cells in other parts of the body. In recent years, Dr. Schmidt and his colleagues have demonstrated that cannabinoids can combat cancer pain and proliferation in a mouse model.1 Dr. Schmidt said cannabinoids have been shown to be particularly good at treating cancer pain and therefore he is optimistic that Sativex may be beneficial in treating pain resulting from oral cancer. This product is already approved in Canada as an add-on treatment for pain in patients with advanced cancer.

Urgent Need for New Treatments

The American Cancer Society has estimated that approximately 37,000 Americans will develop oral cavity or oropharyngeal cancer and an estimated 7,300 will die of these cancers in 2014.2 These cancers are approximately twice as common in men as in women. Human papillomavirus (HPV) transmitted through oral sex, excessive alcohol consumption, and tobacco use are believed to be the leading causes of new cases.

James Hitt, MD, PhD, an anesthesiologist at Roswell Park Cancer Institute, Buffalo, NY, said that there is a great need for improved pain management for patients with oral cancer. He noted that radiation is often used to treat these cancers and is associated with significant dysphagia and odynophagia. “Successful treatment of patients with severe odynophagia can be very difficult, and there is a need for alternatives to around-the-clock opioids,” Dr. Hitt told Clinical Pain Advisor.com. “Patients with odynophagia can be plagued by pain each time they swallow, and that type of intermittent but frequent pain can be very difficult to control.” He said there are some topical options for treating pain in the oral cavity, pharynx, and esophagus, but the duration of effect is short and patients with the most severe pain often end up on continuous high-dose opioids.

Medical oncologist Gregory Masters, MD, based at the Helen F. Graham Cancer Center, in Newark, DE, said that he believes a marijuana spray product is worth investigating. He explained that many patients with oral cancer are looking for treatments that are more homeopathic and less toxic. He said that many turn to the Internet and can end up wasting their money on therapies that are unproven and may be of little benefit. Dr. Masters added that rigorous trials are needed to confirm whether Sativex or any form of (edible or inhaled) marijuana product is beneficial.

Studies have suggested that cannabinoids can have a positive effect on immune function and may have antitumor activity. If the current trial points in that direction and an acceptable side-effect profile can be confirmed, then oncologists could have Sativex as part of their cancer treatment armamentarium relatively soon. “I think they will be prescribing it in the next 2 or 3 years,” Dr. Schmidt said in an interview with ClinicalPainAdvisor.com. “The two big classes of analgesics come from plants. We have opium (which is derived from poppies) and aspirin comes from willow bark. So it is not surprising that we find [another treatment] that comes from a plant.”

References

  1. Saghafi N, Lam DK, Schmidt BL. Cannabinoids attenuate cancer pain and proliferation in a mouse model. Neurosci Lett. 2011;488(3):247-251.
  2. American Cancer Society. What are the key statistics about oral cavity and oropharyngeal cancers? http://www.cancer.org/cancer/oralcavityandoropharyngealcancer/detailedguide/oral-cavity-and-oropharyngeal-cancer-key-statistics. Accessed June 26, 2014.
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