Dr. Roi Dagan, director of the head and neck program at the UF Health Proton Therapy Institute, is among the leading experts on proton therapy for this disease site. He will be in Japan next month to present research on head and neck cancer during the scientific sessions at the Particle Therapy Co-Operative Group’s 56th Annual Conference, the premier international proton therapy gathering of scientists and professionals. Following is a Q&A with Dr. Dagan about head and neck cancers and proton therapy.
Q: April is head and neck cancer awareness month. What should people know about this type of cancer?
A: Head and neck cancers are not one cancer. There are over 20 sites where cancers of the head and neck originate and many different types of cancers. Cancers can arise from the mouth, throat, nose, sinuses, voice box, skin of the face, and salivary glands. The most common cancer of the head and neck is called squamous cell carcinoma and arises from the lining of our mouth and throat. Head and neck cancers account for about three percent of all diagnosed cancers, and an estimated 50,000 people will be diagnosed in the US in 2017.
The outcomes of patients with head and neck cancer, unlike some other cancers, will heavily depend on the quality and/or effectiveness of local therapies such as surgery and radiation. These tumors tend to not spread to other parts of the body unlike lung cancer or colon cancer. Also, the delicate normal tissues of the head and neck are integral to so many parts of our daily life, such as the way we look, how we speak and sound, or what we can eat. Although radiotherapy is very effective for many of these cancers, it can have a severe negative impact on quality of life, often resulting in significant pain from sores in the mouth and throat, loss of taste, severe dry mouth, and difficulty swallowing.
Because these cancers are rare and the anatomy of the head and neck is complex, treatment of these cancers should be performed at centers with multidisciplinary subspecialty expertise. Multiple studies have demonstrated improved survival and quality of life outcomes in patients with head and neck cancers treated at such centers.
Q: Are there ways to prevent head and neck cancer?
A: The best way to reduce your risk of a head and neck cancer is to stop smoking or using tobacco products like chewing tobacco or snuff. Heavy alcohol use is also a potential risk factor for developing head and neck cancer.
We are seeing an increase in cancers that occur in the oropharynx – the tonsils, tongue base, soft palate and pharyngeal wall – that are caused by the human papillomavirus (HPV). This is the same virus that leads to cervical cancer in women. One way to reduce the risk is to have the HPV vaccination. It is recommended for boys and girls beginning at age 11 to be vaccinated to reduce the risk.
Q: What about preventive screening?
A: There are really no standard screening tests. Because of the rarity of these cancers, population-based screening is not likely to be cost-effective. However, now most dental professionals will perform an oral cavity cancer screening exam during routine dental examination.
Head and neck cancers are usually diagnosed when symptoms are present such as a lump in the neck, trouble swallowing, or a sore that doesn’t heal, bleeding from the mouth or throat, or a change in your voice (hoarseness). These can be symptoms of other less serious conditions, but you should talk to your doctor so the proper assessment can be made at as early a stage as possible.
Q: What role does proton therapy have in treating head and neck cancer?
A: The advantages of proton therapy over conventional techniques will vary by disease site in the head and neck. In some situations there will be clear advantages, and in others not. Generally, we can leverage these advantages in one of two ways depending on the specifics of each individual’s case. In some, we may use the advantages of proton therapy to increase the intensity of treatment without risking additional complications and/or side effects, and thereby, we can improve the probability of controlling the cancer. One example of this is in cancers that occur in the nasal cavity and surrounding sinus cavities where the use of aggressive surgery and conventional radiotherapy is limited by the adjacent delicate normal tissues, such as the eyes, visual pathways, and brainstem. Here, we have successfully applied more aggressive treatment, and our studies show that after proton therapy, more than 80 percent of patients are living without local disease recurrence following proton therapy (and 90 percent after complete resection and proton therapy). Historically, the best we ever did in this disease site with conventional therapy was 50 to 60 percent.
In cancers that occur in the salivary glands that are lateralized to one side of the neck and in oropharyngeal cancers, we are able to use proton therapy to reduce the side effects of therapy. Here, we can significantly reduce the severity and duration of taste loss, inability to swallow and development of mouth sores. Patients treated with protons don’t lose as much weight because they are able to tolerate the treatment better due to less radiation to normal healthy tissue.
Q: These seem like excellent results. Is there more that can be done with protons for head and neck cancer?
A: We are continuing to actively explore ways to better harness this technology. Recent improvements in proton delivery systems, image-guided therapy, and immobilization technology to better target the head and neck region could open up the doors for more patients with head and neck cancer to take advantages of proton therapy.