Sarcomas are tumours that pose a challenge in terms of diagnosis and treatment. They are a rare group of malignant tumours that arise from connective tissues of the body, unlike most other cancers that tend to arise from the lining surfaces of various organs such as skin, stomach and colon.

These tumours may arise from any type of connective tissue including muscle, bone, fat, nerve or even blood vessels. As they can occur at any age (from childhood all the way to later years), affect almost any part of the body and manifest in many different ways depending on the tissue of origin and location, diagnosis can be challenging.

Additionally, they tend not to be seen on the surface of organs, posing difficulties during evaluation and may often get misdiagnosed as benign lesions such as cysts or lipomas (benign fat tumours).

The most common forms of sarcoma cancer

In my practice as a bowel surgeon, the most common sarcomas I run into as part of my work are those found in the abdomen. As they are varied in origin, these lesions can be found most commonly either in some part of the intestinal tract such as Gastrointestinal Stromal Tumour (GIST) in the stomach, small intestine or even the colon and rectum; in the abdominal wall or the retroperitoneum (the posterior part of the abdominal wall).

Unfortunately, due to the nature of these tumours being deep from the surface, we normally could only pick them up incidentally during a scan or scope. If they have grown large enough to have any symptoms, they usually would have already become very challenging to manage.

One of the most common type of lesions we tend to pick up incidentally on scopes are GISTs. GIST is a type of tumour that originates from the nervous tissue of the bowel called the Interstitial Cells of Cajal, which normally help to regulate peristalsis which is the natural movement of the intestines to push food down the tract.

GISTs tend to be mostly found in the stomach, although they also develop in the other parts of the intestinal tract from the oesophagus down to the small intestine, colon and rectum. This group of tumours are specifically different from the traditional sarcomas as we know, as they tend to have a very specific mutation in the genes that cause the disease, and also respond to a certain type of targeted therapy using Tyrosine Kinase inhibitors.

Symptoms, diagnosis and treatments

Symptoms that sarcomas can present with vary according to the location and cell type of the tumour itself. Most often, if the sarcoma is not too deep from the body surface such as on the leg, it will present itself as a firm to hard lump on the body. If the sarcoma is deep within the body cavity such as in the stomach wall or in the pelvis, it will manifest with very vague discomfort or even no symptoms at all. Severe cases may present with an acute emergency, such as an intestinal obstruction with vomiting and severe abdominal pain.

Diagnosis of sarcomas generally rely on imaging as they are deep from the surface. The type of imaging again depends on the location of the lesion seen. Common imaging modalities include CT or MRI scans. In some cases gastroscopy and colonoscopy can also identify lesions in the intestinal wall such as a GIST.

Generally speaking, treatment of sarcomas relies on surgical removal or the tumours with clear margins to reduce the risk of recurrence. However, as the tumours can be large and deep and close to many vital structures, surgery may not always be possible. Other possible treatments include radiation, chemotherapy and targeted therapy to try to shrink the tumours to a point where it can be removed safely surgically.

Thankfully, with the advent of improved instrumentation and technology such as laparoscopic and robotics, I have been able to offer minimally invasive treatment options for smaller forms of sarcomas, especially GISTs. However, for larger sarcomas, resection will generally require an open approach to give the best chance of a clear margin and lowest risk of recurrence.

Taking action to lower sarcoma risk

As most sarcomas develop in people with no risk factors, prevention would be crucial. Currently, there is unfortunately no sure way to prevent sarcoma but there are still ways to reduce the risks of getting it. Quitting smoking, the biggest risk factor for sarcoma, can significantly lower the risk. Other recommended ways are avoiding exposure to certain chemicals, limiting exposure to radiation and being aware about your family history.

In addition, it is advisable to seek medical attention for painless growths that can be felt with the hands in areas of the extremities, trunk, head and neck; and for numbness, swelling of an extremity or bladder symptoms.

Contributed by Dr Eugene Yeo, General and Colorectal Surgeon from TEN Surgery Group at Mount Elizabeth (a member of Healthway Medical Group).

Images: Envato