A desmoid tumor is a growth located in your connective tissue. This is the tissue that gives flexibility and strength to areas of your body like your bones, muscles, and ligaments. These tumors can occur in any part of your body.
Desmoid tumors are similar to scar tissue in that they’re fibrous. Since they don’t spread to other areas of the body, they’re not generally thought of as cancerous. However, they can invade the surrounding tissue aggressively and be very difficult to surgically remove. Desmoid tumors often recur, even after they’ve been completely removed.
Desmoid tumors are considered to be sporadic because it’s unclear what causes the majority of cases. Most desmoid tumors have a particular gene mutation called beta catenin, but experts aren’t sure what causes the gene to mutate.
A small number of desmoid tumors are caused by a genetic condition called familial adenomatous polyposis (FAP). People with the mutations causing FAP are prone to having hundreds of polyps in their intestines and often go on to develop colon cancers.
Desmoid tumors usually affect tissue that is easily moved and elastic. Due to their location, a tumor often exists for a long time before it’s discovered. It’s usually only noticed when it’s grown large and pushed aside the surrounding tissues.
The symptoms of desmoid tumors can vary greatly and are dependent upon the tumor’s size and location, and how far it’s spread. For this reason, each person with a desmoid tumor can experience the symptoms differently, but some of the most common symptoms are:
- swelling or a lump that isn’t painful
- soreness or pain (caused when the tumor is compressing muscles or nerves)
- pain in the bowels (caused by obstruction)
- difficulty using the area of your body that has been affected, such as your legs, feet, arms or hands.
The treatment of desmoid tumors is complicated. If you’re diagnosed with one, it’s best for you to be evaluated by experts in sarcoma to determine the appropriate course of treatment for you.
So little is known about desmoid tumors and there is currently no cure, so people who are affected are often asked if they will participate in clinical trials.
When possible, desmoid tumors will be surgically removed. The procedure will usually take between three and five hours. Recovery typically takes a month or less.
However, there is a high rate of recurrence with surgery alone. Twenty-five to 40 percent of affected individuals who have surgery can have a local recurrence, which is a return of the tumor at or near the original site.
The aim of surgery is to remove the entire tumor and minimize the risk of a recurrence. Your doctors will analyze your risks and decide whether recurrence is likely for you. If you are low risk for recurrence, surgery is usually your best option. But if you are high risk, this may not be the case.
Surgery is usually difficult and sometimes even impossible for desmoids in the abdomen. The decision to operate is a complicated one and will need to be carefully considered by a multidisciplinary team of doctors and surgeons at a specialist sarcoma hospital.
Where surgery is not an option, there are alternative methods of treatment to consider, particularly for tumors in the intestines, nerves, organs, or blood vessels.
Radiotherapy is a good option for many people who are unable to have surgery. It can also be used in addition to surgery or chemotherapy. Radiotherapy usually lasts for 6 to 8 weeks, but evidence that the tumor has shrunk can take months or even years to show. Radiotherapy is often not an option for tumors that occur within the abdomen because of the size of the area that needs to be treated and the risk of radiation damage to vital organs. There is also a risk in some cases that radiotherapy will cause other cancers. Treatment options should be discussed carefully with your medical team.
Radiofrequency ablation is a new technique where needles are inserted into the tumors and radiofrequency waves are conducted through the needles to heat the tumor intensely. It has led to some desmoid tumor shrinkage, but this method has only been used minimally, and the long-term results are as yet unknown.
Chemotherapy is a chemical drug that will usually be injected into the veins. There are many different varieties, and most will have wide range of short- and long-term side effects.
There are some specialist sarcoma centers that are determined to understand desmoid tumors and find a cure. There are several new treatments being studied and a number of anecdotal reports of different treatments having positive effects. There is no single medical treatment accepted for desmoid tumors.
The most common complication of desmoid tumors is local recurrence, which happens in around 70 percent of cases.
Life expectancy depends on the type of tumor and where it’s located. It’s usually positive for people with abdominal and extra-abdominal tumors, but less so for people with intra-abdominal tumors due to the complications that can arise. Repeated surgeries can cause further complications that are associated with higher risks of fatality.
The outlook for people who develop desmoid tumors can vary greatly and depends upon the size and location of the tumor, as well as the chosen course of treatment.