What is a Desmoid Firbomatosis?
Desmoid tumors (also called desmoid fibromatosis) are benign fibrous growths that occur rarely in the general population (5 to 6 per 1 million per year) but frequently in one of the familial cancer predisposition conditions known as familial adenomatous polyposis (FAP) or Gardner syndrome, affecting between 3.6% and 20% of patients.
About 2% of all desmoids arise in patients with FAP. Desmoids may occur in any musculoaponeurotic tissue structures of the body, although they tend to be in extremities and spinal areas in the general population and in the abdomen in FAP. Sporadic desmoid tumors are more common than those associated with familial adenomatous polyposis.
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What is FAP?
Familial adenomatous polyposis: A genetic disease characterized by the presence of numerous precancerous polyps in the colon and rectum. The polyps usually begin to form at puberty, and colon cancer almost always develops later in life. Abbreviated FAP. FAP is inherited as an autosomal dominant trait. Most people who receive the gene manifest the disease, although the expression of FAP can vary markedly from person to person. The gene that is mutated in FAP is the APC (adenomatous polyposis coli) gene on chromosome 5. Surgery is often necessary to remove the colon in order to prevent the development of cancer. A milder type of familial adenomatous polyposis has been identified that is inherited in an autosomal recessive manner. This is referred to as autosomal recessive familial adenomatous polyposis and is caused by mutations in a different gene known as MUTYH. Also known as familial polyposis, familial polyposis coli.
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Desmoid Tumors are Rare
In the United States, approximately 900 people are diagnosed with desmoid tumors every year. This means that out of a million people approximately 2 – 4 people are diagnosed with desmoid tumors each year. Experts believe that the numbers are likely to be far greater because of the difficulty in correctly diagnosing this disease. Because of inconsistent and inaccurate reporting procedures, accurate statistics about the number of desmoid tumor cases have not been kept. Individuals between the ages of 15 and 60 are most often affected, but this disease can occur in anyone. The average age is 30’s to 40’s. They are slightly more common in women than in men (2:1), and there is no significant racial or ethnic distribution.
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How is Desmoid Fibromatosis Treated?
If you are diagnosed with a desmoid tumor it is recommended that (if possible for you and allowed by your insurance) you be evaluated in a hospital with experts in sarcoma. These hospitals are usually designated as NCCN (National Comprehensive Cancer Network) centers but not all NCCN centers have expertise in sarcoma. Before making an appointment it is good to know whether they have experts in sarcoma. Ideally, patients with desmoid tumors should be evaluated by a multi-disciplinary team which includes surgeons, medical oncologists, radiation oncologists, geneticists and nurses.
Here are a list of possible treatments:
Observation or “waiting and watching.” Desmoid tumors display a wide range of behaviors. This can range from shrinking spontaneously without any intervention, to remaining stable or growing rapidly. In some circumstances, it is reasonable to just watch the tumor carefully with images and/or physical examination. How often you need scans and/or physical exams during a “wait and watch” period will vary for each situation and your treating physician will discuss this with you.
Surgery. Historically, most people with desmoid tumors underwent some form of surgery. Over the last few decades, it is increasingly being recognized that these tumors have a high risk of returning even with surgery. While statistics may vary, about 25 to 40 percent of patients who undergo surgery can have a local recurrence (return at or near the original site). The goal of surgery is to remove the entire tumor and minimize the risk of recurrence. Scientific research has shown that some types of desmoid have much higher risk of recurrence after surgery than others.
Radiation Therapy. Radiation therapy may be an effective option for a few patients in special circumstances. The dose and duration of radiation is highly variable and your radiation oncologist will discuss that with you. Both the short-term and long-term side effects from radiation should be carefully considered. In general, many sarcoma experts do NOT recommend radiation out of the concern for developing a new (aggressive) cancer due to the radiation. In conclusion, the decision to undergo radiation is a complex one and needs to be discussed carefully.
Thermal ablation. Thermal ablation does not use radiation but rather heat or cold to kill the desmoid tumor. This is an emerging technique where needles are inserted into the tumor and thermal waves are used to heat or freeze the tumor. High-frequency ultrasound is another technique which uses ultrasound waves to destroy the tumor. These techniques are only suitable for certain types of desmoid tumors. Overall, this is a relatively new technique and the experience to date is limited to a few centers, and the long-term results are not yet known. In conclusion, the decision to undergo ablation (hot, cold or ultrasound) is a very technical and complex one and needs to be discussed carefully with the interventional radiologist. Only a few highly specialized centers have expertise in treating desmoid tumors using these techniques.
Medical Therapy. There is no single accepted medical treatment for desmoid tumors. Based on your medical health and nature of your desmoid tumor, your medical oncologist will discuss with you the best options for you. Numerous reports of individual cases show shrinkage or stabilization of tumor size or at least improvement in symptoms after a very wide variety of treatments. Chemotherapy is a chemical drug that is usually injected in the veins. A few chemotherapies that are commonly used include: doxorubicin, Doxil (liposomal doxorubicin), dacarbazine, methotrexate, vinorelbine and vinblastine. These are toxic chemotherapies that can have a wide range of short and long term side effects. There have also been anecdotal reports of using sulindac (non-steroidal anti-inflammatory) or anti-hormonal agents such as tamoxifen, however the true efficacy of these drugs has not been fully investigated in clinical trials. A new class of agents called tyrosine kinase inhibitors (e.g. sorafenib) has shown benefit in desmoid tumors by shrinking the tumors or slowing down the growth. These are pills taken by mouth at home.
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