For Keith Wilson, MD, watching the emergence throat cancers related to the human papilloma virus (HPV) has been almost like watching the emergence of a new disease. In the past, oropharyngeal cancers (of the tonsils and base of tongue) were typically related to smoking and/or excessive alcohol consumption. Today they are frequently caused by HPV, and they are showing up in younger people. Fortunately for Dr. Wilson and his patients, the cancers are highly treatable, and a new robot is giving surgeons at the UC Neuroscience Institute more dexterity in the confined spaces of the mouth and throat than they have ever had before.

“Oropharyngeal cancers now have reached an epidemic proportion, and the main culprit, the main reason for the epidemic, is human papilloma virus,” said Dr. Wilson, Director of the Head & Neck Division in UC’s Department of Otolaryngology and a member of the UC Brain Tumor Center at the UC Neuroscience Institute, one of four institutes of the UC College of Medicine and UC Health.  “We have an influx of patients who smoked only briefly or didn’t smoke at all, and now they have cancers of the base of the tongue and the tonsils. Men outnumber females in the distribution, but we’re seeing a younger distribution, a younger population. Where the average smoker-drinker patient we saw was in their 50’s, the average patients with HPV-related oropharyngeal cancers are in their 40’s.”

Dr. Wilson said that individuals newly diagnosed were probably exposed to HPV 20 to 30 years earlier, when they were in their early 20s or late teens. He attributes the rise to changes in sexual practices. The rise is occurring in the United States and Europe, for example, but not in India or the Middle East.

The majority of people exposed to HPV do not go on to develop tonsil or base-of-tongue cancer, Dr. Wilson said. “Much like women and cervical cancer, there’s a significant percentage who will be exposed and may have limited infection and then clear it.” In a minority of cases, the tumors will metastasize and behave aggressively.

Dr. Wilson is seeing three to four new patients a month with the condition, while his partners, Keith Casper, MD, and Yash Patil, MD, are treating a similar number of patients.

The majority of patients with HPV-related cancers undergo radiotherapy (radiation treatment) and chemotherapy because their lymph nodes are already involved. The most common symptom of cancer of the throat is not a sore throat but rather an enlarged lymph node, the result of metastasis from the throat.

Those who do not have lymph node involvement, or who have only one affected lymph node, will undergo robotic surgery and, occasionally, radiotherapy. “The patients whose cancer is discovered in its earlier stages are the ones we tend to treat with the robot,” Dr. Wilson said. “If we can get clear margins on the primary cancers, we can often save the patients any additional treatment.”

The robot, a Da Vinci Surgical System manufactured by Intuitive Medical, provides 3-dimensional viewing that is superior to what surgeons normally see through a microscope or the naked eye, Dr. Wilson said, and it facilitates surgical maneuvering in the back of the mouth and the throat. “It’s hard to get your hands in there to be able to work. The robot has wristed arms, which move in the same way your wrists move, and they’re holding smaller instruments. So your ability to cut, your ability to sew, your ability to dissect is so much better working with the robot in small places. It’s the reason why the colorectal surgeons, the urologists, and the gynecologists, who are all working down in the pelvis, are finding the robot to have such a tremendous advantage for them as well. With this wristed instrumentation you can do things as if you’re working in a wide open space.”

Dr. Wilson, who did his training with the robot in March 2012, is using it not only to remove cancers of the tonsils and base-of-tongue, but also to treat some lesions on the voice box. Robots are not yet being used to treat vocal cords.

Whether HPV-related cancers are treated surgically or with radiation and chemotherapy, the outcomes are mostly positive. “If you are a non-smoker and don’t have a significant tobacco history and you have an HPV-related cancer, your cure rates are in excess of 90 percent, probably on the order of 93 percent, which for cancer is outstanding,” Dr. Wilson said. “And even with advanced-stage cancer, you have a 90-percent-plus chance of being cured. If you smoke and have an HPV-related cancer, the cure rates drop down into the 71-percent range.”

The big surprise is that smokers with oropharyngeal cancer and HPV have a better prognosis than smokers with oropharyngeal cancer who do not have HPV. The cure rates for smokers with throat cancer who do not have HPV hover around 50 percent. Dr. Wilson describes the phenomenon as “very bizarre,” but very interesting.

“What is it about this virus that seems to render the tumor more susceptible to treatment or makes it less hearty?” Dr. Wilson asked. “That’s the question that a lot of researchers are looking at. I don’t know the answer myself, but there are some really smart people looking into it.”

— Cindy Starr

Related:
Head and Neck Surgeons See Rise in Oropharyngeal Cancers Caused by HPV >>