Sarcoma: what are the warning signs and when should you see a specialist?

Sarcoma is a form of cancer which can develop in bones or in the body’s soft tissues, including cartilage, fat, muscle or fibrous tissue. What could feel like a fatty lump in the skin or pain in the joint may just be a sarcoma. In this article, a consultant medical oncologist provides an overview of the symptoms of a sarcoma, and when patients should seek an expert’s insight.

What is sarcoma?

Sarcoma is a type of cancer that specifically forms in the connective tissues of the body. This includes the muscles, cartilage, bones, tendons, ligaments, blood vessels, and lymphatic tissues. There are two main categories of sarcoma: bone sarcoma and soft tissue sarcoma.

Who is most at risk of developing sarcoma?

Sarcoma is a rare cancer, and its exact cause is still unknown. However, several risk factors are associated with it, including:

• Genetic mutations: Certain inherited genetic conditions can raise the risk of developing sarcoma. Examples include retinoblastoma, neurofibromatosis type 1, and Li-Fraumeni syndrome.
• Radiation therapy: Patients who have received radiotherapy for other cancers are at a higher risk of developing sarcoma several years after treatment.
• Chemical exposure: Prolonged exposure to specific chemicals, including vinyl chloride, herbicides, or arsenic, can increase the risk of developing sarcoma.

What are the signs of sarcoma?

The symptoms of sarcoma will differ according to its location, size, and the rate of progression. In many cases, the early stages will not be accompanied by notable symptoms, and when symptoms do appear, they can be misconceived as related to other illnesses before sarcoma is suspected.

In soft tissue sarcoma, a prominent lump or swelling is the primary sign. It can start off as painless but as time goes by there may be heightened pain or sensitivity around the lump.

In bone sarcoma, there tends to be pain, typically in the limbs or pelvis, that is not clearly attributed to an injury. There may not be a lump that the patient can feel or see externally.

For sarcoma forming in the gastrointestinal tract, stool may begin to carry blood or appear black and oily as the cancer progresses.

When should I see a specialist?

Patients ideally will seek medical advice when they notice ‘red flags’ of sarcoma lumps, such as:

• Rapidly growing (bigger than 5cm) or changing in shape
• Painful
• Feeling ‘deeply’ rooted, as in not just on the surface level
• Occurring around muscles or alongside bones

Patients who also experience sudden stiffness and reduced mobility, and unexplained fatigue and weight loss should consult a doctor.

Regardless of cause, blood in stool, particularly if it is darkly coloured, should always be cause to see a physician.

How is sarcoma diagnosed?

Sarcoma diagnosis typically involves a complete medical history and physical examination to start off, primarily to evaluate the patient’s risk factors and rule out other possible ailments.

If sarcoma is suspected, then the patient will be subjected to imaging scans and tests so that the tumour can be located and analysed. This can take the form of X-rays, MRIs, or CT scans.

The diagnosis is confirmed with a biopsy, wherein a sample of the tumour tissue is extracted and studied in a laboratory in order to examine the cellular behaviour. This also enables the doctor to determine how far the sarcoma has progressed (also known as the ‘stage’ of the disease).