Definition and Overview
Liposarcoma is the most common type of adult soft tissue sarcoma (cancer of connective tissues). The disease, which originates in fat cells of deep soft tissues, can develop in any part of the body but more than 50% of cases are found in the thigh and about 25% involves the abdominal cavity. The most commonly affected individuals are adults between the ages of 40 and 60. Although this type of cancer is relatively rare (it accounts for just 1% of all cancers), it is known to be difficult to treat because it is usually diagnosed when it has already progressed to its advanced stages.
The four main types of liposarcoma are:
Well-differentiated liposarcoma - The most common subtype of the disease. It is commonly painless and tends to grow and change slowly. It is mostly found in the limbs or retroperitoneum and occasionally in the mediastinum or spermatic cord. It is characterised by the presence of a soft and fleshy mass.
Pleomorphic liposarcoma - This is the rarest subtype and is a high-grade tumour. Pleomorphic means that the cells inside the tumour all look different in shape and size under a microscope.
Myxoid liposarcoma - An intermediate to high-grade tumour that accounts for about 35% of all liposarcomas. It is often observed in adults between the ages of 30 and 50.
Dedifferentiated liposarcoma - This occurs when a low-grade liposarcoma changes and transforms into a high-grade tumour.
One of the things that make liposarcoma different from other types of cancer is that they are less likely to spread (metastasise) to other parts of the body. However, it is common for them to recur in the same site following successful treatment.
Causes of Condition
Liposarcoma is very rare, affecting just one person for every fifty thousand people. Because of this, studies about the condition are very limited. Although its causes are yet to be determined, there are reports of liposarcoma patients developing the tumour following an injury. However, scientists have ruled out trauma as well as benign lipomas as causes of the condition.
During the early stages, patients do not notice any liposarcoma symptoms besides a painless, deep-seated mass in their soft tissue. When the disease progresses, and the tumour grows, it puts pressure on surrounding structures causing pain, functional disturbance, and other symptoms, such as:
Kidney failure (if the tumour is compressing the kidney)
Limited range of motion in the limbs
Varicose veins enlargement
Who to See and Types of Available Treatments
Diagnosing liposarcoma cancer begins with a thorough physical exam. If the lump is at least 5cm in size, is firm, deep-seated, and fixed to underlying structures, imaging tests are performed to gather more information. These tests include magnetic resonance imaging (MRI) scan and x-ray followed by a needle or surgical biopsy, which provides adequate details enough for an experienced radiologist to confirm a liposarcoma diagnosis as well as determine the stage and extent of the disease.
Low-grade means that the tumour is slow-growing, less likely to spread, and less aggressive.
Intermediate-grade means that the tumour is slightly more aggressive.
High-grade means the tumour is fast growing, very aggressive, and is more likely to spread to other parts of the body.
Stage 1 - Low-grade and localised cancer (has not spread to other parts of the body)
Stage 2 - Localised tumour that is slightly larger than stage 1 liposarcoma tumour
Stage 3 - Localised high-grade tumour
Stage 4 - Cancer that has spread to other parts of the body
Just like other types of cancer, the complete surgical removal of the tumour is often recommended to patients with liposarcoma. The goal is to remove the cancer along with a wide margin of healthy tissue around it. If the tumour is located in the arms or legs, surgeons perform a procedure called limb-sparing surgery to spare the involved limb. However, in about 5% of cases, amputation becomes necessary to cure the condition and restore the patient to a functional life.
Radiation therapy is also a mainstay in liposarcoma treatment. It is performed to ensure that no cancer cells have remained following surgery and to minimise the risk of recurrence. It involves the use of high-energy radiation beams to kill cancer cells. The therapy can be performed either before or after surgery. If performed before any surgical procedure, its goal is to reduce the size of the tumour so it can be safely removed.
Chemotherapy, on the other hand, is recommended in patients with an increased risk of recurrence and those suffering from metastatic liposarcoma. Chemotherapy drugs that have yielded favourable results include US FDA-approved trabectedin and eribulin mesylate.
Liposarcoma prognosis is based on the disease’s subtype. The five-year survival rates are as follows:
Well-differentiated liposarcoma - 100%
Myxoid liposarcoma - 88%
Pleomorphic liposarcoma - 56%
Patients are scheduled for several follow-up appointments following the successful surgical removal of liposarcoma. They are required to undergo a series of tests despite the absence of symptoms of liposarcoma to detect metastasis. These tests include CT and MRI scans as well as a chest x-ray.
In the case of recurrence, it is important for patients to undergo treatment as soon as possible. Treatment for recurring liposarcoma is the same as with primary cancer and may involve surgery, chemotherapy, and radiotherapy. Secondary cancers can recur in the same site or other parts of the body such as the brain or liver.
Patients may also elect to participate in clinical trials using newest drugs and other alternative treatment methods.
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Skubitz KM, Cheng EY, Clohisy DR, Thompson RC, Skubitz AP. Differential gene expression in liposarcoma, lipoma, and adipose tissue. Cancer Invest. 2005. 23(2):105-18.
Tayal S, Classen E, Bemis L, Robinson WA. C-kit expression in dedifferentiated and well-differentiated liposarcomas; immunohistochemistry and genetic analysis. Anticancer Res. 2005 May-Jun. 25(3B):2215-20.