Q: My brother had lingering hoarseness and a sore throat. When he finally went to the doctor, he was diagnosed with tonsil cancer. He’s in treatment, but it’s been tough. Chemo makes him sick, and radiation is doing a number on his throat and salivary glands, making it hard to eat. He’s on a feeding tube, but he has lost a lot of weight and is fatigued. I’m worried about him. I never heard of tonsil cancer before this. I’d like to help spread awareness.

A: Tonsil cancer is a type of head and neck cancer. Head and neck cancers include cancers of the tongue; the back of the tongue, which you can’t see when you look in the mirror; the tonsils; or the throat, which includes parts like the larynx or voice box. Other rare cancers include salivary gland cancers and cancers in the sinuses and nose.

Tonsils, located on the left and right sides of the back of the throat, are part of the immune system, which protects the body against infection. Tonsils are part of the lymphatic system and have lymphoid tissue. That’s why they can look lumpy and bumpy. They’re filled with immune cells. That same lymphoid tissue is on the surface of the back of the tongue. Cancers that arise in the tonsil or back of the tongue are classified as oropharyngeal cancer, and approximately 70% of these are caused by HPV.

Head and neck cancers, especially those caused by HPV, are more common in men. The most common way in which HPV head and neck cancers are found is from it spreading into the lymph nodes in the neck. The story we often hear is, “I was shaving, and I felt a lump in my neck.” Most of the time patients don’t have a lot of other symptoms. They may notice discomfort when they’re swallowing or a sensation that there’s something in their throat that doesn’t feel right.

HPV is a virus that almost everybody will get exposed to in their lifetime. The primary mode of transmission is sexual. Most people get exposed in their teenage years or early 20s. The virus typically doesn’t cause any symptoms, and there is no treatment. Most people’s immune system will clear the virus from the body after exposure.

However, in approximately 10% of people, the virus is not cleared, and they become chronic carriers of HPV and at risk for cancer development decades later.

HPV-associated cancers tend to have a higher cure rate. When somebody is diagnosed with a type of head and neck cancer, we test to see if the cancer has spread into lymph nodes or other parts of the body.

If the cancer has not spread, treatment is based on the patient’s needs, and it usually inclu des a combination of surgery, radiation or chemotherapy. But if a patient’s cancer has spread to another organ, it’s typical to undergo chemotherapy and immunotherapy.

In 2016, the Food and Drug Administration approved immunotherapy to treat advanced head and neck cancer. Research is ongoing into therapeutic vaccines that try to get the body’s immune system to recognize and then fight the cancer.

The HPV vaccine is FDA- approved for those ages 9 to 45. For cancer prevention, we know from studies that earlier is better, before sexual activity begins, but we also know there’s still benefit over time, even up to age 45.

In addition to vaccinating yourself and your loved ones against the HPV virus, other tips to prevent head and neck cancers include:

Stop smoking or using tobacco products. Better yet, don’t start.

Drink alcohol sparingly, if at all.

Consider healthy behaviors, including physical activity and a plant-based diet with more fruits and vegetables.

— Katharine Price, M.D., Oncology, Mayo Clinic, Rochester, Minnesota

Mayo Clinic Q&A is an educational resource and doesn’t replace medical care. Email a question to MayoClinicQ&A@mayo.edu.