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The majority of primary tumours are diagnosed as slow growing lumps. Diagnosis usually takes place using a combination of scans and a biopsy of the tumour.

Difficulty of diagnosis 

Salivary Gland Cancers can often be asymptomatic or show symptoms that are confused with other less serious conditions. (You can hear more about ways in which this happens in the ‘Our Stories’ section of the website.)  These difficulties in diagnosis can lead to missed opportunities.  Delays in diagnosis can mean that the disease is further progressed and if so, that more extensive treatment may be needed.

Diagnostic Tools

Magnetic Resonance Imaging (MRI): This is a type of scan that uses strong magnetic fields and radio waves, to manipulate the protons in the water of your body to provide detailed images of your tissues.  These scans are used for both diagnosis and monitoring. The scanner itself is a large tube, which you lie inside.  If you are claustrophobic then you should discuss this before the scan.  The scans are loud, so you will wear headphones. They take between 15-90 minutes.  If you have a metal fitting e.g. pacemaker, you may not be able to have the scan. 
MRI scans are readily available on the NHS in centres across the UK. 

Positron Emission Tomography (PET): These scans produce detailed 3-dimensional images and highlight any abnormal areas.  By injecting a radiotracer (which is essentially radioactive glucose) into your arm after you have been fasting, and analysing which tissues take up this glucose, cancer cells can be identified.  MOST cancer cells take up glucose faster than normal cells and so will ‘light up’ on the PET scan. One of the problems with diagnosing Adenoid Cystic Carcinoma is that it does not always take up glucose faster than other cells. This means a negative result on a PET scan, doesn’t necessarily mean that ACC tumours aren’t present. 
PET scans are readily available on the NHS in centres across the UK. 

PET-CT Scan:  PET scans are often combined with CT scans to produce even more detailed images.

Computerised Tomography (CT) Scan (aka CAT scans): This uses X-rays and a computer to create detailed images of your body structures while you pass through a tube.  As well as being used for diagnosis, these scans can also be used for planning surgery and radiotherapy treatment or monitoring. The scan takes around 10-20 minutes and may involve the use of a contrast dye that will be injected in your arm half way through. 
CT scans are readily available on the NHS at many centres across the UK. 

Biopsy: This is the term used for taking a small sample of tissue from your body for analysis and diagnosis.  Where possible, this will be taken without general anaesthetic.

Cancer staging

A cancer stage is used to describe the size of a tumour, how deeply it has grown, and whether it has spread to other parts of the body. Cancer staging systems are standardised frameworks doctors use to determine the most effective treatment plan, estimate prognosis, and allow researchers to compare outcomes across clinical trials [1]. 
Staging acts like a map showing where the cancer is located and how far it has moved from its starting point. The original stage number stays the same throughout treatment, even if the patient gets better [2].
A cancer stage is determined by imaging, lab tests and biopsies carried out by health professionals.

TNM staging system: The TNM staging system, also called the American Joint Committee on Cancer (AJCC) staging system, is one of the many systems used to describe the amount and spread of cancer in the body:
T: Tumour
N: Node
M: Metastasis
In the TNM system, numbers follow each letter to provide specific details about the cancer. The T score describes the size and extent of the main (primary) tumour, usually ranging from T1 to T4, with higher numbers indicating a larger or more advanced tumour. The N score details spread to nearby lymph nodes: N0 means no nodes are affected, while higher numbers show that more lymph nodes contain cancer. Finally, the M score indicates metastasis (how far the cancer has travelled) to distant parts of the body, where M0 means no metastasis and M1 means the cancer has metastasised [1].

Number staging system
Cancer can also be described using a less detailed number system. In the number system, the higher the number or roman numeral, the more advanced the cancer is. Letters can also be used to describe the cancer in more detail [1].

Stage 0: Abnormal cells that have not spread to nearby tissue.
Stages I and II: Small tumours that are local and contained.
Stage III: A larger tumour that may have grown into nearby tissues or local lymph nodes.
Stage IV: Cancer that has metastasised to distant parts of the body, also called metastatic or secondary cancer [3].

Cancer grading
Health professionals sometimes refer to cancer by grade. This is a measurement of how abnormal cancer cells and tissues appear under the microscope compared to normal, healthy cells. The cancer grade indicates how aggressive the cancer is by how quickly it is likely to grow and spread; for example, high-grade refers to an aggressive cancer [3].

Summary
Cancer staging is essential as it describes where the cancer is and how far it has spread, which allows doctors to choose the best treatment. Establishing the stage also gives doctors a reliable baseline to explain what to expect, predict the likelihood of recovery, monitor if a treatment is working, and adjust the care plan over time.

References

  1. Institute NC. Cancer Staging. Available online: https://www.cancer.gov/about-cancer/diagnosis-staging/staging (Accessed: 29/09/2026
  2. Brierley J, Gospodarowicz M, O'Sullivan B. The principles of cancer staging. Ecancermedicalscience. 2016; 10:ed61.
  3. Amin MB, Edge, S. B., et al. AJCC Cancer Staging Manual. 8th ed. American Joint Committee on Cancer: Springer; 2017.

Useful Resources

Professor Ali Khurram, Dean of School of Clinical Dentistry and Professor and Honorary Consultant Pathologist at the University of Sheffield talked about the 'Complexities in Diagnosis' of Salivary Gland Cancers, at one of our gatherings in 2021.  You can watch a recording of his talk here.

You can also see a presentation from the SGC UK team at a Pulse 365 Virtual event 'Public Health, Pain and Rare Diseases' in April 2023 here.  This was specifically aimed at the Primary Care/General Practitioner ('GP') audience and examples of presentations that they may encounter.

Last Updated October 2026