Liposarcoma is a rare type of sarcoma (bone and soft tissue cancer) that develops from lipocytes (fat cells). It can occur in any part of the body, but is most commonly found in the muscles of the limbs (arms and legs) or in the abdomen. Liposarcoma is the most common type of soft tissue sarcoma in adults.
Liposarcoma is more common in males, and is generally diagnosed between the ages of 40-60. However, it can develop at any age. Paediatric cases of liposarcoma are generally diagnosed in a patients’ teen years or in their early 20’s.
Types of Liposarcoma
There are four types of liposarcoma, which are classified by their cellular appearance under the microscope, and the genetic mutations involved.
Well-differentiated liposarcoma
The well-differentiated subtype is the most common type of liposarcoma. This type generally forms in the limbs or in the retroperitoneum (a space located behind the abdomen that contains many important bodily structures such as the kidneys), and is often associated with a mutation on chromosome 12. It is usually low-grade and less aggressive than other types of liposarcomas.
Dedifferentiated liposarcoma
Dedifferentiated liposarcomas are the second most common subtype of liposarcoma. It often develops as the result of a well-differentiated liposarcoma, and usually occurs in the limbs or retroperitoneum. It tends to be more aggressive than the well-differentiated subtype, and has a higher metastasis rate.
Myxoid liposarcoma
Myxoid liposarcoma is a less common form of liposarcoma. It is often the result of a genetic mutation that affects chromosomes 12-16. Myxoid liposarcomas are more common in the paediatric age groups, and usually develops in the limbs. It is usually a low-grade cancer.
Round cell liposarcoma
Round cell liposarcoma is a high-grade form of myxoid liposarcoma. This type generally forms in the leg. This subtype is generally more aggressive and may have a less favourable prognosis.
Pleomorphic liposarcoma
Pleomorphic liposarcomas are the rarest form of liposarcomas. This subtype usually develops in the limbs, and is more common in older populations. It is often high-grade with high recurrence and metastasis rates, and often spreads to the lungs. It is associated with mutations in the RB (retinoblastoma) tumour suppressor gene.
Treatment
If liposarcoma is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health. In adult patients, your tumour will be staged and graded to help determine the best treatment option for you. There is currently no standard staging system for children with liposarcomas.
The treatment options for adults and children with liposarcomas are similar. These options may include:
- Surgery, potentially including:
- Partial or total tumour resection (depending on the location).
- Limb amputation (in extreme cases only).
- Radiation therapy.
- Chemotherapy.
- Targeted therapy.
- Immunotherapy.
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia Treatment Options page.
Risk factors
Some of the risk factors associated with liposarcoma include:
- Prior radiation treatment.
- A family history of cancer.
- Prior damage to the lymphatic system.
- Exposure to certain hazardous chemicals, such as vinyl chloride.
- Certain genetic syndromes.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Early symptoms
In the early stages of liposarcoma, there may be no signs of the disease. As the cancer progresses, some of the following symptoms may appear.
Symptoms of liposarcoma in the limbs include:
- A growing lump under the skin.
- Pain and swelling in the affected region.
- Weakness of the affected limb.
- Numbness in the affected region.
Symptoms of liposarcoma in the abdomen include:
- Abdominal pain, cramping and/or swelling.
- Loss of appetite/feeling full after little food.
- Constipation.
- Blood in stool.
- Black/tarry stool.
- Unexplained weight loss.
- Blood in vomit.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have a liposarcoma, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Imaging & blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-ray and/or ultrasound, depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
Biopsy
Once the location of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. Once a sample has been removed, it will be sent to a lab and analysed for cancer cells.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage liposarcomas have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.