Liposarcoma is cancer that starts in the fat cells. It is a type of soft tissue sarcoma.
A liposarcoma can grow anywhere but most often develops in the abdomen or limbs.
Liposarcoma is among the most common soft tissue sarcomas. The American Cancer Society (ACS) estimate that around 12,750 people in the United States will receive a diagnosis of soft tissue sarcoma in 2019.
They also predict that there will be around 5,270 deaths from soft tissue sarcomas in the same year.
As liposarcomas are rare, a cancer doctor, or oncologist, will often refer people with liposarcoma to another specialist.
In this article, we look at liposarcoma, the symptoms, and how doctors treat this type of cancer, plus give pictures of the disease.
A liposarcoma is a rare form of tissue cancer. Adults most often develop liposarcomas, but, in rare cases, they may occur in children.
People may confuse liposarcomas with fatty deposits of tissue, or lipomas, which are not cancerous. It is extremely rare for an existing noncancerous lipoma to become cancerous. Instead, most liposarcomas occur due to a new tumor.
The treatment plan and outlook for liposarcomas depend on the type. Also, some liposarcomas grow slowly and are easy to remove, while others grow quickly and can spread to other organs.
The symptoms of a liposarcoma depend on the location of the tumor.
Liposarcoma in the arms or legs may cause pain, swelling, or weakness in the affected limb.
In the abdomen, a liposarcoma can grow in the retroperitoneum, or membrane covering the abdominal organs. When this occurs, a person may have symptoms that include:
- weight gain
- stomach pain or swelling
- constipation or bloody stool
- problems urinating
A liposarcoma may not cause any symptoms at all until it is large enough to press on neighboring organs. This pressure may cause pain, swelling, or disrupt the function of nearby organs, such as the lungs, liver, or other abdominal organs.
Liposarcomas occur when previously healthy cells develop errors in their genetic code, or DNA, and start to multiply quickly.
While the exact cause for this change is unclear, liposarcoma typically develops in males from 50–65 years of age.
Risk factors for all types of soft tissue sarcomas include:
- a history of radiation to the abdomen or another body part
- a history of genetically related cancer
- exposure to cancer causing chemicals
- damage to the lymphatic system
Doctors have not linked lifestyle choices, such as smoking or poor diet, to a heightened risk for liposarcomas.
Next, the doctor will perform a biopsy to test a sample of the tissue.
Because liposarcomas are rare, it is important that an experienced, specialist surgeon removes the tumor. A pathologist can identify the cells that characterize liposarcomas after the removal of the tumor.
After confirmation of a liposarcoma, doctors will probably categorize the tumor into one of four subtypes.
The main types of liposarcoma include:
- Well-differentiated: This is the most common type. The cells tend to be slow growing or low grade and closely resemble fat cells.
- Myxoid/round cell: These are intermediate to high grade tumors that have a distinct, circular pattern of cancer cells. High grade tumors tend to spread more quickly than low grade types.
- Pleomorphic: This is the rarest but most aggressive form of liposarcoma.
- Dedifferentiated: This is a high grade type. It develops from a tumor that initially displayed low grade cancer cells.
Knowing the type of cell can help a doctor identify how well the tumor will respond to chemotherapy, as well as allow them to determine the outlook.
Treating a liposarcoma often depends on its type and location.
Often, the first step is to remove the tumor surgically, along with a wide margin of healthy cells.
A tumor will sometimes be in a location where a surgeon cannot remove all cancerous cells because doing so could harm nearby organs.
Similarly, surgery may not be effective as the only course of treatment if cancerous cells have spread from the tumor to other locations.
A doctor may recommend radiation therapy after surgery to destroy any remaining cancer cells. Radiation can also help a doctor shrink the tumor before surgery.
Although a doctor can request chemotherapy to destroy cancerous cells, it is not usually effective for low grade liposarcomas.
Chemotherapy targets fast growing cells. Low grade liposarcomas may not grow quickly enough for chemotherapy to work.
The U.S. Food and Drug Administration (FDA) have approved two chemotherapy drugs that they call orphan drugs to treat liposarcomas.
Orphan drugs are medications for rare disorders that have fewer than 10,000 cases a year that doctors have diagnosed.
Examples of these medications include:
- eribulin mesylate (Halavan)
- trabectedin (Yondelis)
The FDA have approved these treatments for liposarcomas that have spread. They have also approved them for when surgery will be dangerous or ineffective, and a liposarcoma has failed to respond to previous chemotherapy regimens.
The ACS do not have specific survival rates for liposarcoma. The likelihood of surviving for 5 years beyond a liposarcoma diagnosis will also depend on the type, stage, and method of treatment. According to Memorial Sloan Kettering Cancer Center, the survival rate for people with high grade liposarcoma is under 50%.
The survival rate indicates how likely a person is to live for a certain length of time after diagnosis. The ACS calculate these for the overall category of soft tissue sarcomas.
If a soft tissue sarcoma does not spread from its original site, a person has a 5-year survival rate of 81%. With the most aggressive soft tissue sarcomas, this reduces to 16%.
Many liposarcoma tumors are recurrent, meaning that they return after treatment.
Doctors will recommend frequent follow-up testing to make sure that a person's cancer has not come back. Examples of these tests may include imaging scans, such as an MRI, and physical exams.
Many medical and research centers are working to develop drugs to treat liposarcomas. Ideally, this research will provide new treatment regimens that can help extend the life expectancy of a person with this type of cancer.
Is it hard to find a liposarcoma specialist?
Liposarcomas are rare, so it may be difficult to find a doctor outside of a large medical or research center that has seen many of these cases.
You can consult your physician or oncologist for a referral or recommendation to a specialist or contact a large medical or research center that may be more likely to have doctors that specialize in diagnosing and treating sarcomas.Yamini Ranchod, PhD, MS Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.