Desmoid tumors are benign growths that develop in the connective tissues inside the body. Though they’re not considered cancerous, they can be invasive and grow into other, nearby parts of the body.

Desmoid tumors are rare. According to the National Organization for Rare Disorders (NORD), only 2 to 4 people out of 1 million are diagnosed with this type of tumor in the United States each year.

While these tumors can occur in any part of the body, they’re more common in the arms, legs, and abdomen. Where the tumor develops can determine a lot about how serious or life threatening the condition will be.

The life expectancy for people with desmoid tumors is good, but some factors can influence each person’s outcome. In this article, we explore more about the life expectancy for people with desmoid tumors, what influences life expectancy, and how often these tumors recur.

Desmoid tumors are rare. They’re also rarely fatal.

According to a retrospective review published in the American Society of Clinical Oncology, 96 percent of people with desmoid tumors are alive 5 years after diagnosis, 92 percent after 10 years, and 87 percent after 15 years.

There are three types of abdominal desmoid tumors, classified by where the tumor first forms:

  1. Abdominal tumors: These begin in your abdominal wall.
  2. Intra-abdominal tumors: These form in the tissue that connects organs with your abdomen.
  3. Extra-abdominal tumors: These occur in connective tissue found in other locations, such as the shoulders, upper arms, and thighs.

Certain types of desmoid tumors have lower survival rates. For example, people with abdominal and extra-abdominal desmoid tumors have typical life expectancies. But people with intra-abdominal desmoid tumors have lower survival rates.

In a 2012 study, participants with stage I and II intra-abdominal desmoid tumors had 95 and 100 percent 5-year survival rates. Participants with stage III tumors had 89 percent 5-year survival rates. That rate dropped to 76 percent for participants with stage IV intra-abdominal desmoid tumors.

This drop in life expectancy is likely the result of life threatening complications that are more common with advanced tumors. These complications include intestinal obstruction and sepsis.

While they aren’t always fatal, desmoid tumors can be painful. If they are large, they may cause pain, which can be severe. They can also grow into nearby tissues, organs, or other structures, like:

  • abdominal muscles
  • kidneys
  • lungs
  • blood vessels
  • nerves

The primary factors that influence life expectancy for people with desmoid tumors include:

  • Where the tumor is located. Intra-abdominal desmoid tumors are considered more serious and often lead to lower life expectancy. Desmoid tumors in the head and neck are also considered more serious and potentially life threatening.
  • How quickly the tumor is growing.
  • If the tumor is compressing any nearby structures. These might include the organs, nerves, or blood vessels.
  • Whether treatment can shrink or control the growth of the tumor.

Other factors in people with desmoid tumors can affect survival rates. These include:

One 2012 study found that the 5-year survival rate of people with stage IV intra-abdominal desmoid tumors with any of the above factors was 53 percent.

Because desmoid tumors are so rare, it’s difficult to know true life expectancies. Any survival rates or expectancy statistics are just estimates, and each person’s outlook varies for several reasons.

If you’ve received a desmoid tumor diagnosis, consider consulting with experts at a specialist sarcoma hospital. While desmoid tumors are considered benign, or noncancerous, the specialists who treat soft tissue cancers are often better equipped to handle your tumor, treatment, and outlook.

This care team or your doctor can help you understand your life expectancy and the outlook for your individual situation.

Removing desmoid tumors is very difficult. Surgery is not considered a first-line treatment because it can be a complicated undertaking.

Desmoid tumors also often recur, or come back, after surgery, even if the surgeon removes the tumor entirely. The Desmoid Tumor Research Foundation suggests that 25 to 60 percent of people who have surgery to remove a desmoid tumor will see a recurrence at or near the original site.

According to Orphanet, altogether, 70 percent of people with a desmoid tumor will see a recurrence. That’s why your care team may opt to leave the tumor in place if you are at a low risk. People with high risk may receive different treatment options.

Desmoid tumors are rare, benign growths in the connective tissues of the body. While they can occur anywhere, they’re more common in the arms, legs, and abdomen.

Life expectancy for people with this type of tumor is high. However, certain factors can influence each person’s individual life expectancy. Tumor size, stage, location, and complications may change the outlook. The treatment you receive will also have an impact on your outlook.

If you have received a desmoid tumor diagnosis, work with your doctor or medical team to understand your outlook and what it means for your life expectancy. Keep in mind that these tumors are rare, and they are also rarely fatal.