What is Sarcoma?

July 30, 2021

Sarcomas represent only 1% of the total burden of malignancy in the population, and because of their rarity are not commonly encountered by members of the medical profession. Indeed, most members of the public will not even be aware they exist.

What type of cancer is Sarcoma?

A sarcoma is a type of cancer that starts in tissues of mesenchymal cell origin, quite similar to adenocarcinoma which is from glandular cells, and squamous cell carcinoma from epithelial cells. Bone and soft tissue sarcomas are the main types of sarcoma. Soft tissue sarcomas can originate virtually from any form of soft tissue, like fat, nerves, wall of blood vessels, deeper layers of skin and so on. So they are very varied in origin, behavior, and can be found in any part of the body.

What are the different types of Sarcoma?

• Angiosarcoma develops from the cells that make up the walls of blood vessels
• Bone sarcoma is a cancer that starts in the bone
• Chondrosarcoma originates from cartilage
• Ewing's sarcoma also from bones, and most common among younger age group
• Fibroblastic sarcoma from fibrous tissues eg muscles, tendons, ligaments
• Gastrointestinal stromal tumours (GIST) arise from some specialized cells of the smooth muscle of the stomach or intestines.
• Liposarcomas, which develop in fatty tissues
• Leiomyosarcomas, which originate in smooth muscles
• Rhabdomyosarcomas, which start in skeletal muscles
• Synovial sarcomas, which start in tissues that surround joint
• Dermatofibrosarcoma forms in the tissue under the skin, commonly found in the trunk or limbs.

Sarcomas are extraordinarily heterogeneous, comprising more than 70 distinct histological subtypes, with additional layers of biologic variability as a result of differences in genetic complexity and driver molecular mutations. There is also particularities in clinical factors such as age of onset and anatomic site of affliction.

What is the most common type of Sarcoma in Malaysia?

Soft tissue sarcomas are by far the most common. Osteosarcomas (sarcomas of the bone) are the second most common, while sarcomas that develop in the internal organs, such as the ovaries or lungs, are diagnosed least frequently.

Is Sarcoma hereditary?

They are usually acquired during life rather than having been inherited before birth, but can also arise in the setting of a recognized heritable cancer predisposition syndrome. E.g. neurofibromatosis, Li Fraumenis syndrome, etc.

What causes Sarcoma?

They occur mainly due to DNA mutations, which are usually acquired during life. Many of these acquired mutations may result from exposure to radiation or cancer-causing chemicals. In many cases, they occur for no apparent reason.

Where does Sarcoma usually start in the body?

In general, they occur throughout the body, but depending on the type, there is a predilection for certain sites eg you’ll find angiosarcoma occurs most commonly on face and scalp, but can also affect skin, liver, breast, and spleen tissue; whereas Ewings sarcoma and osteosarcoma most commonly affects long bones, GIST tumours will affect mostly the stomach and intestine.

How aggressive is Sarcoma, how fast does it spread and is it deadly?

"Agressiveness" is a very subjective term that may not best describe sarcomas. Firstly, sarcomas in general are quite rare & hard to detect and diagnose early. For a cancer patient, it is more dangerous to have a news of being diagnosed with sarcoma rather than carcinoma. This is due not only because of its rarity, but also due to the fact that sarcomas have widely variable behavior pattern, and progression and subsequent treatment may be influenced by variety of factors.

Some of these factors are grade, stage, and cancer biology in-toto, as determined by their molecular and gene profile characteristics (intrinsic). Sometimes they can be extremely aggressive, especially in a situation where the patient may have been compromised by poor immune status, age, co morbid conditions, “bad genes”, and location of the cancer (extrinsic factors).

In these situations the sarcomas can invade neighbouring tissues, and have high metastatic potential through the genes that determine their migration, invasiveness and angiogenesis. On the other hand, they may be more indolent and have a fairly good outlook, even if diagnosed very late.

Is Sarcoma a ‘silent killer’ (no symptoms) If not, what are the symptoms?

In comparison to aggressive cancers like ovarian cancer, which are indeed “silent killers”, sarcomas tend to grow and spread relatively slower. Delayed diagnosis is usually because the symptoms and signs are masked by the slow growth, absence of pain, being unable to feel them due to deep seated location, and other doctor-asociated and socioeconomic factors. However the high grade tumours can spread quickly to lymph nodes and through lymphatic and vascular channels.

What does a Sarcoma lump feel like? Is it like a breast cancer lump which is hard and defined?

A sign of adult soft tissue sarcoma is a lump or swelling in soft tissue of the body. A sarcoma may appear as a painless lump under the skin, often on an arm or a leg. Sarcomas that begin in the abdomen may not cause signs or symptoms until they get very big.

Soft tissue sarcomas are hard to spot, because they can grow anywhere in your body. Most often, the first sign is a painless lump. As the lump gets bigger, it might press against nerves or muscles and make you uncomfortable or give you trouble breathing, or both.

How is Sarcoma diagnosed?

A diagnosis of sarcoma is made by a combination of clinical examination by a doctor and imaging tests. Soft tissue sarcomas are hard to spot, because they can grow anywhere in your body. Most often, the first sign is a painless lump. It is confirmed by the results of a biopsy of the mass or lesion detected clinically. There is unfortunately no salvia, urine, stool or blood tests that can be used to diagnose a sarcoma. Tissue samples, obtained from either a biopsy or from an excised tumor, must be analyzed by a skilled pathologist who specializes in these rare cancers in order to render a diagnosis of sarcoma & histological sub type.

What treatment options are available for Sarcoma patients, and how effective are they?

Best treatment for sarcoma, is surgery if in early stage, or if it is of low grade (not likely to spread to other parts of the body). Most people diagnosed with a soft tissue sarcoma are cured by surgery alone.

More aggressive sarcomas are harder to treat successfully. It is more likely to be cured if all of the cancer can be removed by surgery. Those that are high grade and larger than 2 inches (5 cm) are often treated with a combination of surgery and radiation therapy. Radiation therapy or chemotherapy may be used before surgery to shrink the tumor and make removal easier. Hence the importance of multidisciplinary/multimodal treatment strategies in treating sarcomas.

What is the survival rate of sarcoma patients?

The overall 5-year survival rate for sarcoma is 65%. About 60% of sarcomas are found as a localized sarcoma. The 5-year survival rate for people with localized sarcoma is more than 80%.

Can we prevent ourselves from developing sarcoma?

At this time, there's no known way to prevent this cancer. The only way to reduce risk some soft tissue sarcomas is to avoid exposure to risk factors like radiation, certain chemicals like herbicides, dioxin, etc, whenever possible. Still, most sarcomas develop in people with no known risk factors. And for those people needing radiation therapy, there's usually little choice, but to accept the small but significant risk. It may also be a new norm in the future to know one’s genetic predisposition, eg whether there is a link with conditions such as neurofibromatosis, Li-Fraumenis syndrome, retinoblastoma gene. But for the moment, there are not a lot of genetic tests to accurately predict one’s risk of sarcomas. “It appears to be too rare a condition to worry about cost effective screening and detection strategies”.

Can Sarcoma be cured completely?

Sarcomas can be cured, as with most cancers, if patients present at an early stage, when surgical resection is feasible. If you look at the survival rates, you will notice the difference in survival based on stage. However there are other factors that determine the outcome, very important of these are grade of tumour, histological type of sarcoma, site of tumour, age and overall health, and so on. Quality of treatment also appears to play an important part, especially in the more advanced stages, as those that tend to do well are those that have access to multimodality treatment strategies.

Overall the 5 yr survival rate is about 65%
EER Stage 5-Year Relative Survival Rate
Localized 81%
Regional 57%
Distant 16%
All SEER stages combined 65%

Dr. Jayendran Dharmaratnam
Consultant Clinical Oncologist (Visiting)
Columbia Asia Hospital - Bukit Rimau

MBBS (India), FFR.RCSI (Radiotherapy) (Ireland)

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