What is a salivary gland tumor (SGT)?
The salivary glands include several small organs close to or within the mouth, which produce the saliva. The parotid gland is the largest salivary gland. It is located in front of the ear and is the most frequent site for SGTs.
Several types of tumors may develop from the salivary gland cells. The benign tumors are called adenomas and grow only in the salivary glands. The malignant tumors are carcinomas, which very rarely can spread beyond the salivary gland.
In infants, vascular tumors such as hemangiomas and lymphangiomas may also be seen in this location. Lastly, several other malignant tumors may arise or spread to the salivary glands and must therefore be considered as differential diagnoses.
Who gets a salivary gland tumor and why?
SGTs may develop in all age groups. However, there are most commonly seen in adult patients. In children and adolescents, it is unclear, why these tumors develop.
Is there a risk for brothers / sisters to develop the same cancer or other types of cancer?
Generally, no – since the development of the SGTs has not been linked to any known inherited predisposing syndrome or factor.
Are SGTs all the same?
There are very many different types of SGTs, and the distinction between them requires examination of the tumor tissue in pathology laboratories after the tumor removal.
What are the typical symptoms and sign of SGTs?
SGTs typically present as painless lumps. Parotid tumors may even be visible as lumps located in front of the ear. As the facial nerve runs through the parotid gland, parotid tumors may lead to facial nerve palsy; the smile may become asymmetric or the child may have problems closing the eye lid. If a tumor develops in the submandibular or in the smaller glands, the child may have problems swallowing.
Which investigations are necessary to diagnose a child with SGT?
Ultrasound scan is the first investigation to detect the tumor and assess its location.
Magnetic resonance imaging (MRI) of the head and neck region is indicated. It allows for evaluating the deeper parts of the salivary glands and the rest of the head and neck.
If a malignant tumor is diagnosed, the staging investigations should include also other radiological examinations, such as a chest X-ray.
Are there different stages of the disease?
Yes, most tumors are limited to the salivary gland. However, carcinomas may spread in the regional lymph nodes in the neck (lymph node metastases), and very rarely to the lung or other distant sites.
What about the SGT treatment?
The SGTs should be removed completely, and in all adenomas and most carcinomas, no additional therapy is required.
In some parotid tumors, the close proximity to the facial nerve may interfere with complete resection. If the situation is equivocal, it may be better to perform a limited resection of the tumor and to spare the facial nerve until the pathological diagnosis is made. In case of malignant tumors, a second surgery may then be discussed. In malignant tumors, the regional lymph nodes may also be resected (so called lymph node dissection) in order to remove metastatic lesions. If lymph node metastases are diagnosed, the radiotherapy of this region should be considered.
What are the results of treatment?
The prognosis of salivary gland tumors is very good. Nevertheless, both adenomas and carcinomas may recur, mostly after incomplete resection. In most of the cases, another surgical resection is required, and in case of incomplete second resection, additional therapies, such as radiotherapy, may become necessary.
What research is carried out for SGTs?
The central collection of clinical data and national and international analysis of patients with SGTs have allowed for the development of risk-adapted treatment strategies. With these strategies, the prognosis of patients has further improved. High-risk patients can be identified, and low risk patients can be spared unnecessary radio- or chemotherapy.
What EXPeRT is doing for children with SGTs?
Currently, EXPeRT is performing a large international analysis of approximately 200 patients with SGTs, treated in France, Germany, Italy, Poland, and the United Kingdom. The experience gathered from this and from previous national analyses forms the basis of the recommendations made above.
The main goals of EXPeRT for pediatric patients with SGTs, include:
- Collection of data of patients from European countries
- Development and distribution of diagnostic and therapeutic recommendations
- Providing treatment centers with an advisory service
- Establishment a collaborative network with other international specialists
- Support of genetic/biological projects