The new organ, highlighted by the blue arrows, is implicated in vastly reduced outcomes during cancer treatment. In turn, these newly discovered glands possess the potential to greatly improve the standard of life for many cancer patients.
The unsung multitasker of the body, our salivary gland system, is responsible for producing the saliva required for speech, mastication, swallowing, digestion, tasting, and infection control in the oral cavity, as well as dental hygiene. It performs this amazing list of lubrication via its three paired major glands and approximately 1000 minor glands spread throughout the soft mucosa of the aerodigestive tract.
As you can imagine with great responsibility comes even greater problems when this system goes awry. Damage or an interruption to our salivary gland network can cause adverse events known as xerostomia or dry mouth and dysphagia, the inability to swallow due to a lack of saliva. Both these conditions are very common in patients undergoing radiotherapy for head and neck cancer, including tumors in the throat or tongue. Due to the fact radiotherapy can damage the salivary glands, leading to many complications.
Thus affected cancer patients often experience impaired food intake, digestion, speech problems, and increased risk of caries and oral infections. Of course, these conditions can cause a significant impact on their quality of life. The major salivary glands are therefore regarded as organs-at-risk and are protected during cancer treatment wherever possible. However, despite the three major known salivary glands being bypassed during radiotherapy, it is unclear why patients still suffer complications linked to damaged salivary glands.
A life-changing discovery for cancer patients
Now, a study from researchers at the Netherlands Cancer Institute identifies a previously unknown pair of salivary glands in a completely new location. The team states this new discovery could vastly improve the quality of life for many cancer patients. This is because the new organ can now be protected during cancer treatment like the other major salivary glands to avoid complications. The opensource study is published in the journal Radiotherapy & Oncology.
Recent studies from the group investigated the side effects of radiation on the head and neck. Their study, involving prostate cancer patients, used a new type of scan known as PSMA PET/CT scanning. This new diagnostic was of particular interest as salivary glands show up clearly on this imaging to mark and protect them during treatment.
Whilst studying the novel PSMA PET/CT scan two unexpected areas lit up all the way in the back of the nasopharynx. Interestingly, the new areas looked very similar to the known major salivary glands. Furthermore, as the structures did not fit any prior anatomical descriptions it was hypothesized that it could contain a large number of acini. To explain, these are cells grouped in a raspberry configuration that secrete fluid, an example of which are salivary glands. Additionally, it was posited that the physiological role for these new acinus structures was nasopharynx/oropharynx lubrication and swallowing. The current study based on PSMA PET/CT scanning indicates a previously unknown pair of nasopharyngeal macroscopic salivary glands.
A new imaging technique highlights a new organ
The present clinical trial involves a cohort of 100 participants with prostate or urethral gland cancer. Indeed, a set of these glands, dubbed the tubarial glands due to their location, were identified in the scans of every patient. Additionally, the two new areas that lit up turned out to have other characteristics of salivary glands. Subsequently, this was confirmed in the tissue of two human cadavers.
Results using a microscope show the newly discovered organs are composed of salivary gland tissue. Imaging places them bilaterally near the torus tubarius, with visible draining duct openings towards the nasopharyngeal wall. Specifically, these ducts support the theory that this new anatomical structure is responsible for nasopharynx/oropharynx lubrication and swallowing.
Data findings show when compared to the known major salivary glands, the tubarial glands had the most similarities with the sublingual glands, as opposed to the parotid or the submandibular glands. This evaluation was based on the mucous acini, similar PSMA-ligand uptake, and the presence of multiple draining ducts.
Classifying the new the organ
The lab explains that the accepted definition of an organ is that it consists of more than one type of tissue, with a definite shape and structure whilst performing specific tasks. They go on to state that these glands could therefore be classed as a new organ. This definition is backed by evidence gained from a cadaver study confirming the presence of a defined structure consisting of acini and draining ducts.
Moreover, the association of xerostomia and dysphagia with radiotherapy in a 723 patient cohort indicated a specific function that can be disrupted. The group stresses that these conditions are also associated with damage of the known salivary glands as well as fulfilling one of the conditions in the classification of an organ.
Certainly, for most patients, it may be possible to bypass these newly discovered salivary glands during radiotherapy in the same way known glands are protected during treatment. Importantly, sparing this new organ during cancer treatment provides an opportunity to vastly improve the quality of life for many patients.
The new organ’s ramifications for cancer
The team surmises they have discovered a new organ proffering serious connotations for cancer treatment. Moreover, this new organ represents a previously unknown part of the salivary gland system. The researchers state they now plan to investigate how to spare these new salivary glands in high-risk patients. In summary, if this can be achieved, cancer patients may experience fewer side effects, benefiting their overall quality of life.
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Michelle is a health industry veteran who taught and worked in the field before training as a science journalist.
Featured by numerous prestigious brands and publishers, she specializes in clinical trial innovation--expertise she gained while working in multiple positions within the private sector, the NHS, and Oxford University.