Professional baseball great Tony Gwynn Sr., also known as Mr. Padre, died last month of salivary gland cancer, which he believed was caused by years of using smokeless chewing tobacco. The cancer is a rare form that begins in any of the salivary glands in the mouth, neck or throat. Two adults in 100,000 are diagnosed with salivary gland cancer each year. The chances of survival drop if the cancer has spread to other parts of the body. Dr. Patrick K. Ha, with Johns Hopkins Head and Neck Surgery at Greater Baltimore Medical Center, says new types of treatments and therapies are in the works to treat the disease.
What is salivary gland cancer and how common is it?
Salivary gland cancers are a diverse group of rare malignancies that can involve any of the major salivary glands (the parotid, submandibular and sublingual) or minor salivary glands, which are found within the lip, palate, tongue base, nasal cavity or sinuses. There are numerous different cancers that may arise from the salivary glands, and these may behave differently based on their cell of origin.
What causes it, and who is more likely to get it?
Little is known about the causes of salivary gland cancers. Unlike the more common head and neck cancers, which have a clear association with smoking, drinking or even the human papillomavirus (HPV), salivary gland cancers do not have such strong associations. There may be a link between significant radiation exposure (i.e., treatment level doses) in the development of salivary gland cancers, as well as with some environmental exposures such as nickel alloy, asbestos or woodworking materials. Tony Gwynn believed using chewing tobacco throughout his professional baseball career was the cause of his cancer, but salivary gland cancers aren't as strongly linked to tobacco use as some other types of cancers. Nonetheless, we advise against smoking, using smokeless tobacco or even e-cigarettes. They are all addictive and tobacco products contain carcinogens relevant to other cancers.
We do know that men are more likely to get this type of cancer, with the average age of onset in the mid-60s.
What are the symptoms of salivary gland cancer?
Unfortunately, salivary gland cancers most often present as painless masses in the cheek, neck, or within the sinuses/tongue base. Because most of these masses are slow growing, the development of symptoms occurs relatively late. Depending on which gland is involved, the symptoms may include a visible lump, difficulty breathing, swallowing problems or pain. Late symptoms might include facial weakness/drooping, numbness or visual changes.
How is it diagnosed and is it hard to detect?
The ultimate diagnosis is made with a biopsy. A distinction can often be made between benign and cancerous masses with a small needle biopsy, but sometimes requires complete removal of the mass to make this determination. Imaging with a CT scan or MRI can be helpful, especially for operative planning. Depending on where the tumor is located, detection can be more difficult. For example, a mass on the outer surface of the parotid or submandibular gland will be more easily felt than a mass growing in the sinus.
How is it treated and what is the likelihood of survival?
Most salivary gland cancers are treated with surgery up front for complete removal, and possibly radiation afterwards, depending on how serious the disease appeared at the time of surgery and under the microscope. Chemotherapy is less well proven to be helpful in these cancers but could sometimes be considered as additional therapy along with radiation. While some forms of salivary gland cancer can be aggressive, most are relatively well treated, and the five-year survival rate can be upwards of 75 percent.
What new therapies are on the horizon for salivary gland cancers?
Currently, there are trials available to examine the role of chemotherapy in salivary gland cancer treatment. Additionally, work is being done to look into targeted therapy which can better treat the cancers without the significant side effects. Unfortunately, because these are rare cancers, we need to perform the basic research to understand how these cancers arise before we can really make significant advancements in their treatment.