Ostrow Researchers Test New Treatment to Prevent Oral Cancer

A new clinic for treating precancerous oral lesions using several treatment options, including the first prospective clinical trial for imiquimod — a medication approved for skin cancer. It could revolutionize oral cancer treatment.

BY KATHARINE GAMMON

ORAL CANCER ISN’T the cancer you think about the most. After all, it ranks eighth in prevalence among U.S. men and 10th for U.S. women. But it’s particularly harmful: Oral cancer has a higher death rate than lung cancer, breast cancer, colon cancer and prostate cancer. It can be deadly if not detected and treated early.

But, treating oral cancer is also uniquely challenging. “It’s horrible, and you can lose part of your tongue,” explains Professor of Clinical Dentistry Parish Sedghizadeh DDS ’01. “There’s so much collateral damage in the treatment of these patients.”

Using Your Own Immunity

The problem is that oral cancer often spreads rapidly — and silently — before symptoms are noticed. Even when it is noticed early by an oral healthcare professional or the patient themselves, doctors have few options but to surgically remove the oral cancer and even some of the healthy tissue around it to truly make sure the cancer is gone.

And, for precancerous lesions, which can present as red or white patches in the oral lining that grow thicker over time, the only thing to do is to monitor the area. Sometimes, that means watching it grow for years, doing biopsies and waiting for the patch eventually to turn into cancer.

Now, a human trial underway at USC may chart a new path in treating precancerous lesions before they ever become oral cancer.

Ostrow researchers are testing imiquimod — a topical immune response modifier cream used to treat precancerous spots on the face or scalp, early types of skin cancer and genital warts — on precancerous patches in the mouth.

Currently only FDA-approved for external use, the cream activates a patient’s own immune cells to attack and kill abnormal cells.

The new trial will study the effects of using imiquimod in and around the oral cavity to better treat precancerous lesions.

Because imiquimod is not for use in a patient’s mouth, doctors would use gauze or a special tray (not unlike bleaching trays) to ensure the cream contacts only the area affected by precancerous lesions.

It could be a lifeline for patients with few other options.

Ostrow’s new OralCare Precancer and Pain Clinic, which is running the trial, opened two years ago, and already has a full patient load and a waitlist. It’s the region’s first and only clinic to treat patients with precancer.

The initial results are encouraging — the researchers say biopsies show that precancerous areas are regressing or completely disappearing after being treated with the cream. “We’re not seeing cancers develop in patients,” Sedghizadeh says. “So, in a way, it’s a cancer prevention trial, because we’re going to follow these patients for years.”

With Cancer, Prevention is Everything

Assistant Professor of Clinical Dentistry Anette Vistoso Monreal serves as the leader over the new OralCare Precancer and Pain Clinic.

She became interested in imiquimod’s potential years ago, first doing retrospective studies of the drug’s use on oral precancer recurrence.

When she came to USC in 2023, she wanted to take steps to move the treatment forward — to stop the precancerous lesions from ever converting into cancer. Since there is no approved treatment, she says, patients are clamoring for new options.

“The word is spreading,” Vistoso says. “It’s a new option for patients, because we are trying to prevent cancer conversion, and with more tools, and of course, with research.”

The clinical trial is ongoing, and the team is analyzing the outcomes before and after treatment. The research also goes beyond the clinic — the team is also comparing patients’ tissue before and after the treatment, to understand any genomic or molecular alterations. Associate Professor of Biomedical Sciences Dechen Lin is working alongside the team, creating organoid models of patients’ own tumors outside the body, to test the drug as well.

Compared to the typical way that oral cancers are studied — using rat or mouse models — the approach is very advanced, Sedghizadeh says.

“Studies are not really done with human patients and organoid models from actual patients. This is really cutting edge.”

It may prove to be a way to rescue patients from a catastrophic disease. “The best way to prevent people suffering from this devastating disease is not to treat it once it’s devastating,” Sedghizadeh adds.

“Prevention is everything, and we have a chemo prevention immunotherapy that can prevent cancer — if it plays out.”