Mammary analogue secretory carcinoma (MASC) of salivary glands is a newly recognised form of carcinoma (cancer that develops in the tissues that line the organs) that develops in the salivary glands. Salivary glands are responsible for the production of saliva, which is a fluid that aids in digestion, prevents your mouth from becoming too dry and supports healthy teeth.
In humans, there are three pairs of major salivary glands located behind the jaw: parotid, sublingual and submandibular. The parotid glands are largest, and are found in the cheeks. The main role of the parotid glands is to initiate the first part of digestion. In most cases, MASC of the salivary glands is found in the parotid glands. The sublingual glands are the smallest and are found on each side of the tongue. These glands produce the least amount of saliva. The submandibular glands are located on the floor of our mouths on each side, and produce the most saliva. There are also several minor salivary glands found in the lips, cheeks, mouth and throat.
This type of cancer gets its name from an equally rare and also newly recognised type of cancer called secretory carcinoma of the breast, which is predominantly found in children. MASC of salivary glands shares genetic and cellular features with this type of cancer.
MASC of salivary glands is usually diagnosed in adults, but it can be diagnosed at any age.
Treatment
If MASC of salivary glands is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for MASC of salivary glands may include:
- Surgery, potentially including:
- Parotidectomy (removal of part or all of the parotid gland(s)).
- Removal of sublingual salivary gland(s).
- Removal of submandibular salivary gland(s).
- Chemotherapy.
- Radiation therapy.
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.
Risk factors
Because of how rare MASC of salivary glands is, there has been limited research into the risk factors of this disease. However, genetic predisposition has been identified as a potential factor that may increase the likelihood of developing this disease.
Early symptoms
Symptoms of MASC in the salivary glands may include:
- A lump in the cheek and/or mouth. This may be slow-growing and painless, or fast-growing and painful.
- Changes in salivation, such as decreased or increased saliva production.
- Skin inflammation in surrounding tissue.
- Inflammation of the lymphatic glands.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have a MASC of the salivary glands, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Imaging and blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-ray and/or ultrasound, depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
Biopsy
Once the location of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. Once a sample has been removed, it will be sent to a lab and analysed for cancer cells.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage MASC of the salivary glands have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.