What Is Soft Tissue Sarcoma?

“Soft tissue sarcoma.” ever heard this term before? If not, it may seem pretty complicated. The key to understanding any diagnosis is knowledge. Read on to find out more about soft tissue sarcomas and increase your knowledge. 

In the medical world, breaking down the terms in a name can give a clear indication of what something is. The suffix “oma” refers to cancer. Sarcoma refers to cancer of the connective tissue. Hence, “soft tissue sarcoma” is a cancer of the “soft” (non-bone) connective tissue like ligaments, vascular tissue and more.

Soft tissue sarcomas are rare, making less than 2% of the cancer diagnoses in the UK. In connection with the different types of connective tissue in the body, the types of soft tissue sarcomas are also diverse. Read on to learn more about the types, diagnosis, treatment and management of soft tissue sarcoma. Always refer to a qualified GP for a medical opinion! 

Overview

Soft tissue sarcoma is a type of cancer- a disease where a cell (known as  cancer cell) starts to divide rapidly and forms a mass of tissue called tumour. In general, sarcoma refers to different types of cancer  that begin in the connective tissue of the body. These may be either bone sarcomas or soft tissue sarcomas, which will l be explained in more detail throughout this article. Soft tissue sarcomas affect the connective tissue all over the body,such as muscle tissue, fat-storing (adipose) tissue, or cells supporting the digestive tract. Soft tissue sarcomas are rare since they account for less than 2% of cancer diagnoses. Since the cell types that can lead to this disease are very diverse, the symptoms, modality of treatment and recovery vary greatly.

Types of soft tissue sarcoma

Soft tissue sarcoma affects soft tissues of the body, which range from muscles and blood vessels to fat, tendons and joint linings. There are many types of soft tissue within the body, and therefore, there are many types of soft tissue sarcoma that develop from them. There are more than 50 types of soft tissue sarcomas and a few are discussed below: ¹  

1. Leiomyosarcoma - the most common type of soft tissue sarcoma in adults. These are tumours in smooth muscle tissue present all over the body (muscles responsible for involuntary actions)
2. Liposarcoma - derived from the word “lipid” meaning fat. These are sarcomas of fatty tissue and account for around 20% of overall soft tissue sarcoma cases. They generally occur on the stomach and the inner thighs
3. Fibrosarcoma - the site of origin of a fibrosarcoma is fibrous tissue, which is connective tissue found at the ends of bones and joints
4. Rhabdomyosarcoma - these are sarcomas developing from striated muscles (skeletal muscles) which are involved in voluntary movement
5. Synovial sarcoma - these are sarcomas where the original cell type involved in tumour formation is unknown. The cells don’t resemble any specific type of soft tissue
6. Angiosarcoma - this type of cancer arises from malignant cells within the walls of blood or lymph vessels
7. Kaposi’s sarcoma - this is also a type of tumour that arises in the vascular tissue and it is one of the few types of soft tissue sarcomas that are caused by viruses. Kaposiʼs sarcoma is caused by a viral infection with human herpesvirus 8 (HHV-8) in immunocompromised individuals²  

Causes of soft tissue sarcoma

Sarcomas most commonly occur in the arms and legs but, just like most types of cancer, their exact cause remains unknown. Sarcoma develops upon the rapid and unregulated division of malignant cancerous cells, which metastasise (spread and invade) other parts of the body creating complications. A normal cell may become a cancerous cell due to mutations within its genetic material (DNA) or due to environmental factors. Soft tissue sarcomas may have different causes depending on the cell type they develop from, the clinical course of the disease and the extent of malignancy (stage of cancer).³ 

Signs and symptoms of soft tissue sarcoma

The symptoms displayed by soft tissue sarcoma depend on the size and location of the tumour, which can be diverse due to the nature of the condition and the various types of sarcoma known to date. Swelling under the skin in the form of a lump, especially if it gets bigger over time, is the most common symptom. If this lump is present in the abdominal area, it might be accompanied by bloatting (the constant sensation of feeling full). If swelling is present around the lungs, it may result in shortness of breath and cough. 

In most cases, soft tissue sarcomas are asymptomatic and the indicators of the disease are mainly a result of the pressure applied by the growing tumour over nearby muscles and nerves.⁴

Management and treatment for soft tissue sarcoma

As soft tissue sarcomas are highly variable in location and the type of tissue affected, their treatment usually varies for Some approaches used for the treatment of soft tissue sarcoma are discussed below:

1. Surgery

Surgery is usually the most common course of action for soft tissue sarcoma. Usually, a surgeon aims to remove the entire tumour along with 1-2 cm of non-cancerous tissue around the tumour as a clear margin to reduce the chances of recurrence. The margin is analysed by microscopy to determine if further surgery is required. Surgery may be accompanied by medication and other types of treatment to prevent remission. ^5. 

2. Radiotherapy 

This therapy involves killing cancerous cells with high-energy rays of light (most frequently X-rays). This may be used after surgery to kill any leftover cancer cells, or it may be suggested before surgery to reduce the tumour size to an operable limit in certain cases.⁶

3. Chemotherapy

Used for metastatic soft tissue sarcomas, chemotherapy drugs are administered intravenously or orally to attack cancer cells. In soft tissue sarcoma, a combination of anticancer drugs is used. In the case of limbs, drugs may be delivered to this specific site; this is called an isolated limb perfusion.⁷ 

4. Immunotherapy 

Immunotherapy is the process of priming someone’s immune system to recognise and kill malignant cells. Certain medications can “activate” the immune system towards recognising cancer cells. ⁸

Diagnosis

The main method of diagnosis for soft tissue sarcoma is biopsy. The exact procedure and type of biopsy depends upon the location and approximate size of the tumour. Common types of biopsy used for diagnosis are core-needle biopsy (where a tissue sample is collected using a wide needle), or incisional biopsy (where a lump of tissue is removed from the body for analysis). The tissue is then analysed by various techniques like FISH, microscopic analysis and antigen tests. Determination of the cancer stage for sarcoma is carried out post-diagnosis depending upon the extent of spread and size.⁹ 

Risk factors

Sarcomas are one of the rarest types of cancer, accounting for up to 2% of total cancer diagnoses in the UK. 

1. Age

As with most other types of cancer, the risk of developing a soft tissue sarcoma increases with age. Even though people of all ages can develop sarcomas, 40% of soft tissue sarcomas are diagnosed in patients aged 65 years and over. 

2. Radiotherapy treatment and radiation exposure

Radiotherapy treatment exposes a patient to large amounts of ionising radiation, which is a known mutagen (a physical or chemical agent  that increases the chances of mutation in one’s DNA or genes). This may affect healthy tissue during radiotherapy or other types of radiation exposure, which could cause mutations in oncogenes (cancer-related genes)  and lead to the development of cancer years down the road. 

The exact risk level depends on other factors like age, radiation dosage, and location of radiotherapy administration. This should not be used to discourage radiotherapy, although a <1% future risk of sarcoma needs to be balanced against the current risk for a malignant tumour. Always consult a qualified medical professional if you feel that a treatment risk is bothering you. 

3. Exposure to certain chemicals

Certain chemicals known as carcinogens can increase the rate of mutation in cells and potentially pose a risk for soft tissue sarcoma. This may be significant in people who are exposed to these chemicals daily in professional settings. These chemicals include iodine-131 and polychlorophenols.

4. Genetic factors

Some genetic conditions and genetic disorders significantly increase the chances of developing sarcoma. These conditions include neurofibromatosis, Li-Fraumeni Syndrome, retinoblastoma, among more. These are genetic disorders that increase the chances of mutations that could lead to the development of cancerous lesions.  

5. Lowered immunity

A few viruses are known to cause soft tissue sarcomas in individuals with compromised immunity (immunocompromised individuals). This may be due to someone suffering from other diseases such as AIDS, or taking medications called immunosuppressants following an organ or graft transplant. 

HHV8 (Human Herpes Virus 8) can cause Kaposi’s sarcoma in such individuals. Epstein Barr Virus has also been linked to leiomyosarcoma.¹⁰ 

FAQs

How can I prevent soft tissue sarcoma

There is no way to prevent soft tissue sarcoma directly. However, maintaining a healthy lifestyle and staying vigilant towards any growing lumps or swellings can help. If you are suffering from any genetic disorder that causes a predisposition towards soft tissue sarcoma, or have undergone significant radiotherapy treatment, seek advice from a qualified medical professional to practice the best preventative practices.

How common is soft tissue sarcoma

Accounting for  2% of all cancer diagnoses, approximately 4300 new soft tissue sarcoma cases are diagnosed in England per year.¹¹ 

What can I expect if I have soft tissue sarcoma

The symptoms can range from a growing lump in the affected area, to having a feeling of fullness in the area around the lump. Depending upon the exact type of sarcoma, the r course of treatment and outcomes may vary greatly.

When should I see a doctor

If you are developing a persistent and/or growing lump on any part of your body, especially if it has reached a size of 5cm or more, refer to a GP as soon as possible!¹² 

Summary

Soft tissue sarcoma is a cancer of the soft connective tissue of the body- it can occur in ligaments, muscle cells, cells of the vascular tissue (blood and lymph vessels) and even fatty tissue. Owning to the diverse cell types that can lead to soft tissue sarcoma, more than 50 types have been discovered and the number is increasing constantly. Being a rare form of cancer, it doesn’t show any distinctive symptoms- it usually presents as a constantly growing lump or swelling anywhere on the body. Diagnosis is carried out by collecting samples from the suspected tissue via biopsy and carrying out a wide range of tests on it (FISH, immunohistological analysis etc.). The exact cause of soft tissue sarcomas remains unknown; however, a few genetic diseases increase the chances of developing one. Immunocompromised individuals or those suffering from HIV/AIDS are at risk for Kaposi’s Sarcoma. It is usually treated via surgical removal supplemented with radiotherapy, chemotherapy and immunotherapy.