Researchers have found previously unnoticed salivary glands in the human throat.
The team from The Netherlands Cancer Institute, which published findings in Radiotherapy and Oncology, coined the new discovery as “tubarial glands,” which they say represent the human body’s “fourth pair of major salivary glands.”
The glands were discovered by surprise when Wouter Vogel, radiation oncologist, and Matthijs Valstar, oral and maxillofacial surgeon, were testing a new scan called PSMA PET-CT, per a news release.
“People have three sets of large salivary glands, but not there,” Vogel said in the release. “As far as we knew, the only salivary or mucous glands in the nasopharynx are microscopically small, and up to 1000 are evenly spread out throughout the mucosa. So, imagine our surprise when we found these.”
The glands are about 1.5 inches long and have a draining duct opening toward the throat. Researchers assume their function is to moisten and lubricate the throat and back of the mouth.
The findings may have implications for cancer patients, study authors said, and suggested that radiation should avoid the glands for better patient outcomes and quality of life. They explained that high-dose radiotherapy can cause damage to salivary glands during head and neck cancer treatment and lead to dry mouth and difficulty swallowing.
“The major salivary glands are therefore regarded as organs-at-risk (OAR) and need to be spared when possible,” study authors wrote, suggesting the newly discovered “tubarial glands” be added to the list.
Researchers studied 100 patients with cancer and two cadavers, finding the glands present in all of them. They also followed 723 patients who had radiation treatment, and found an association between radiation to the glands and complications thereafter.
“For most patients, it should technically be possible to avoid delivering radiation to this newly discovered location of the salivary gland system in the same way we try to spare known glands,” Vogel said in the release. “Our next step is to find out how we can best spare these new glands and in which patients. If we can do this, patients may experience less side effects which will benefit their overall quality of life after treatment.”