The Tubarial Salivary Glands - The Newest Addition to the Salivary Gland Family

                                                         By: Mary Beazely

One would assume that with all the medical technology and research we have, we should know everything there is to know about human anatomy by now. However, it appears we do not know our anatomy as well as one would think. On October 16 of this year, new research from the Netherlands Cancer Institute and the University of Amsterdam was published in Radiotherapy and Oncology about the discovery of what now has the proposed name of the Tubarial Salivary Glands.
 
First of all, what do we already know about our salivary glands? In our bodies we have three pairs of major salivary glands: the parotid glands, the submandibular glands, and the sublingual glands. The parotid glands are the largest pair of the three and produces saliva which aids in starch digestion. These glands are located in front of our ears on the sides of our face. The submandibular glands are a bit smaller, located just under the jaw and produce the majority of our saliva. The sublingual glands are the third pair as well as the smallest, located just below the tongue. We also have thousands of minor glands in our mouths which are very small and not visible. Our glands are important as they produce saliva, which is imperative for dental hygiene, swallowing, keeping our mouth moist and helping with digestion.
 
This newly discovered pair of glands was found to be located in the nasopharynx, which is in the back of our nasal cavity. Wouter Vogel and Matthijs Valstar were the first to spot them. Vogel and Valstar were studying the effects of radiotherapy, specifically the new PSMA PET/CT scan and its side effects on the head and neck region. This new scan is believed to be more effective than the current methods for detecting prostate cancer. A recent study demonstrating the accuracy of this new PSMA PET/ CT scan was published this past March.
 
Antigens are foreign molecules in the body or toxins which cause an immune response to occur.  PSMA is the acronym for Prostate Specific Membrane Antigen, which is located on prostate cancer cells. The PSMA PET / CT scan works by first injecting the patient with radioactive ligands. These ligands are molecules that bind to the cancer cell antigens. The patient then undergoes a combined PET/CT scan. A CT (Computer Tomography) scan uses x-rays and computers to generate an image of the patient’s organs, bones, and soft tissues. The PET (Positron Emission Tomography) scan then detects the radioactive molecules in the patient for imaging. This allows doctors to see where the cancerous cells are and where they are spreading.
 
In their study, Vogel and Valstar observed the scans of 100 prostate cancer patients. In these scans, the salivary glands lit up where expected, but there was also an unexpected region which lit up in the back of the nasopharynx, around the center of the head. This region was consistent in the scans of all 100 patients. More research was executed through a partnership with the University Medical Center Groningen in the Netherlands. In continuing the study, 732 patients with radiation treatment of various doses around the newly found glands were observed for symptoms to find a relationship between xerostomia (dry mouth) and dysphagia (difficulty swallowing).

Patients with head and neck cancer often undergo radiotherapy. Radiotherapy is essentially a cancer treatment that uses high energy beams such as x-rays to kill cancerous cells. Although this process is effective, it can lead to uncomfortable side effects. The main side effects for patients being treated in the head and neck region are trouble swallowing, dry mouth, tooth decay, and other problems associated with poor salivary gland function.
 
This research from the Netherlands Cancer Institute and the University of Amsterdam concluded that there was indeed an association between the radiotherapy dosage and expected salivary gland side effects often observed in radiotherapy patients. This is what confirmed that the newly identified glands in the PSMA PET/CT scan are in fact a pair of salivary glands in our bodies. Doctors do their best to avoid radiotherapy near the salivary glands as much as possible due to the aforementioned negative side effects. This new research will be beneficial to radiotherapy patients, specifically those getting treatment for head and neck cancer. As medical professionals will now be able to avoid the tubarial salivary gland region as they have been doing for the other previously known glands. 

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