Global Health Nexus, Winter 2003

Shedding New Light on Oral Lesions

Halfway through an oral cancer examination, Dr. A. Ross Kerr suddenly turns off the lights and points a glowing blue wand at his patient’s mouth.

“This blue light supplements oral cancer screenings conducted by plain eyesight under standard room lighting,” explains Dr. Kerr, an expert in oral medicine. “We are hoping that the blue light will draw attention to pre-cancerous or cancerous lesions that might otherwise escape notice.”

A complex chemical reaction produces this diffuse, low-energy light. When focused on the mouth, the light may illuminate lesions that could otherwise be missed under standard lighting. Just before the blue light is activated, patients rinse with a dehydrating acetic acid that is believed to make dysplastic lesions become whiter under the blue light’s glow.

Dr. Kerr is conducting a six-month pilot study to evaluate the blue light’s usefulness as a screening tool for oral cancer and pre-cancer. The light has already proved useful in cervical cancer screening. In a related study, Dr. David Sirois, Associate Professor and Chairman of the Department of Oral Medicine and Head of the Division of Reconstructive and Comprehensive Care, plans to compare the light with other oral cancer detection methods.

Both studies are part of a broad new effort to enhance early detection of oral cancer and pre-cancer. Better screening techniques, combined with an understanding of the molecular changes leading to cancer, may result in an improved outlook for those at risk. Researchers ultimately hope to identify genetic markers for oral cancer that could signal a predisposition to the disease long before lesions occur.

Dr. Kerr’s research also focuses on the study of recurrent aphthous ulcers (RAU), a condition commonly known as canker sores. Five to 25 percent of the general population suffers from canker sores. And in selected groups, such as medical and dental students, who are subject to predisposing factors like stress, the rate is between 50 and 60 percent.

“While we’ve been waging a relentless battle against these extremely painful ulcers for as long as anyone can remember, we still have no cure,” Dr. Kerr observes. “For most sufferers, who get a handful of outbreaks a year, treatment is palliative, and includes the use of mucosal coating agents with topical anesthetics to relieve the pain. For those patients who have frequent recurrences or ulcers which take longer to heal, there are treatments available to reduce or even stop the frequent recurrence of ulcers, but their long-term use can cause unwanted side effects.”

Dr. Kerr recently completed a six-month study which found that a topically-applied penicillin troche significantly reduced healing time for minor RAU, which is generally defined as lesions less than 10 millimeters in diameter that heal in approximately a week to two weeks without scarring. On the fourth day of treatment, 43 percent of Dr. Kerr’s subjects who received penicillin reported that their ulcers had healed completely, compared to 15 percent of those who received a placebo and 11 percent who got no treatment. On the sixth day, 90 percent of people had completely healed in the penicillin group, compared to 55 percent and 44 percent in the placebo and no treatment groups, respectively. A total of 100 people participated in Dr. Kerr’s portion of the multicenter study. If the penicillin troche proves successful in larger trials, it may offer a new alternative in the struggle to relieve the pain of aphthous ulcers. Yet the battle to conquer canker sores is far from over. While research has established that factors such as allergies and stress can cause an onset of the condition, the causes of many canker sores remain unknown.

But for now, any significant relief is welcome news for canker sore sufferers, who can find chewing and swallowing painful. And Dr. Kerr points out that pain symptoms disappeared faster in his penicillin-treated subjects than in those receiving a placebo or no treatment at all.