Proton radiation oncologists continue to be optimistic about the early results they are seeing in treating head and neck cancers.
In the Czech Republic, a leading radiation oncologist reports that patients there who have been treated for head and neck cancers with protons are experiencing far fewer side effects than those typically experienced by photon radiation patients.
“Protons have huge benefits,” says Dr. Jiří Kubeš, head of proton therapy at the Proton Therapy Center Czech in Prague. The facility opened in June 2012.
Using pencil beam scanning, Dr. Kubeš and his associates are seeing much smaller doses of inadvertent proton radiation going to critical structures that control the senses of smell, taste, vision and hearing.
As a result, common acute side effects — those that occur during treatment — such as dry mouth or poor saliva production, which can impair eating, are occurring less frequently among head and neck proton patients.
“These patients don’t need tube feeding,” he says. “More than half of patients treated for head and neck cancers with photon radiation require tube feeding.”
Unlike proton beams, conventional photon radiation doesn’t just hit a cancer tumor and stop. Photon rays tend to spread more unintentional — and harmful — radiation to nearby healthy tissues and organs. Those splashes of radiation typically occur with each photon treatment. And later in life, having survived the original cancer, patients may find they’re battling another form of cancer or some type of organ disease.
But the risk of similar side effects arising years later appear much lower for proton patients because their treatment exposed healthy tissues and organs to significantly less inadvertent radiation.
A 32-year-old woman from Slovakia is one such case, Dr. Kubeš recalls. Her name is Gabriela. And shortly after she married, Gabriela experienced an excruciating toothache. Her face swelled. And she felt pressure under her right eye. A CT scan illuminated a 6-centimeter tumor growing in the sinus area of her face. Surgery for Gabriela would risk permanent damage to one eye. Treatment with targeted proton beams dramatically lowered that risk.
“She is in complete remission,” Dr. Kubeš says.
Gabriela did endure some minor side effects during the time of her proton treatments, he said, including a radiation skin rash on her face and increased tiredness. “All of those small side effects went away within a month of her final treatment,” says Dr. Kubeš. “Six months after treatment, we are seeing no side effects from protons.”
Head and neck cancers currently account for about one in five cancer patients who are being treated with protons at the Proton Therapy Center Czech, according to Dr. Kubeš. But he expects the incidence of oropharyngeal cancers, a type of head and neck cancer, to increase in the coming years especially among men and women aged 20 to 50.
Many oropharyngeal cancers, such as tonsil cancer, stem from exposure to the human papillomavirus during sexual contact, he notes.
When caught early and treated with a combination of surgery and protons, tonsil cancer can be eradicated and this group of young and middle-aged adults can lead normal lives, says Dr. Kubeš.
“These patients have an excellent prognosis,” says Dr. Kubeš. “The reduction in late-stage cancer is what’s most desired. We can spare the pharynx. We can spare the esophagus. We can spare the majority of the oral cavity. We can spare the cochlear area that impacts hearing. And we can spare the lower part of the brain.”