Receiving a desmoid tumor diagnosis can be overwhelming, and you’re likely wondering what this means for your (prognosis) outlook. Fortunately, desmoid tumors are benign (noncancerous) growths that rarely cause death. The biggest concern for many living with these tumors is that they cause uncomfortable symptoms.

In this article, we’ll discuss how desmoid tumors affect life expectancy and outlook. We’ll also cover the importance of following up with your oncologist (cancer care doctor) to make sure your desmoid tumor hasn’t progressed or returned.

Desmoid Tumors and Life Expectancy

Desmoid tumors are noncancerous growths that form in the body’s soft tissues. Also known as aggressive fibromatosis, these tumors may grow slowly or quickly. Desmoid tumors are rarely deadly, and many people live long, healthy lives with them. However, aggressive tumors can spread into nearby tissues, causing complications that may become life-threatening.

What Is the Life Expectancy With Desmoid Tumors?

Doctors typically use survival rates to talk about life expectancy with a disease. The survival rate refers to how many people with a disease are alive after a certain amount of time. It’s important to note that these statistics come from studies of dozens or hundreds of people with desmoid tumors. They can’t predict your exact outlook, but they can help you understand how well you may respond to a treatment.

Desmoid tumors are rare — in the United States, they’re diagnosed in just 900 to 1,500 people every year. As a result, few studies describe how desmoid tumors affect life expectancy. The National Cancer Institute notes that this makes it hard for doctors to determine survival rates accurately.

An older study from 1999 reported the survival rate with desmoid tumors over several years. The researchers found that the five-year survival rate was 96 percent. This means that after five years, 96 percent of the people in the study were still alive. The 10- and 15-year survival rates were 92 percent and 87 percent, respectively.

Factors That Influence Life Expectancy With Desmoid Tumors

Researchers have found that certain factors play a role in life expectancy with desmoid tumors. Your tumor location and size, as well as whether you have other conditions, can all affect your outlook with the disease.

Desmoid Tumor Location

Desmoid tumors affect the soft tissues found throughout your body, including:

• The abdominal wall or tissue surrounding the organs in your abdomen
• Mesentery (intra-abdominal tissues), which provide padding and blood vessels to the abdomen
• Extra-abdominal tissues, including the arms, chest wall, shoulders, and legs

The location of a desmoid tumor can affect your prognosis. For example, intra-abdominal tumors are most likely to cause severe complications. They may block the intestines or limit oxygen flow, killing the tissue.

Tumor Size and Symptoms

Doctors typically assign cancerous tumors a stage that refers to their size and spread. Staging is useful for determining a person’s outlook or prognosis for a specific type of cancer. However, there isn’t an official staging system for desmoid tumors, because they don’t spread or metastasize (spread) like cancerous tumors do.

Researchers have proposed a four-stage system for desmoid tumors. The Collaborative Group of the Americas on Inherited Colorectal Cancer (CGA-ICC) developed this system as a way to stage intra-abdominal tumors in people with familial adenomatous polyposis (FAP). This condition causes numerous polyps (abnormal growths) in the colon.

The CGA-ICC system takes into account symptoms, tumor size, and any complications. One study looked at 154 people with intra-abdominal desmoid tumors who also had FAP. After staging the tumors, the researchers found the five-year survival rates were:

• Stage 1 (no symptoms) — 95 percent
• Stage 2 (mild symptoms) — 100 percent
• Stage 3 (moderate symptoms) — 89 percent
• Stage 4 (severe symptoms) — 76 percent

The researchers also looked at other factors that affect life expectancy. Participants who had severe pain, a large tumor, and needed nutrition from an intravenous (IV) injection had a five-year survival rate of 53 percent.

Having Familial Adenomatous Polyposis

Between 10 percent and 15 percent of people living with FAP have desmoid tumors. FAP is an inherited condition caused by changes or mutations in the adenomatous polyposis coli (APC) gene. Those with APC mutations are at a higher risk of developing desmoid tumors. A form of FAP known as Gardner syndrome is associated with desmoid tumors.

The second most common cause of death with FAP is desmoid tumors. They account for 9 percent to 11 percent of deaths, according to Wolters Kluwer UpToDate.

Studies have investigated life expectancy and survival with FAP and desmoid tumors after treatment. A 2023 study looked at 45 people with desmoid tumors whose treatment included surgery, chemotherapy, and radiation. The authors reported that the median progression-free survival (PFS) was 23.4 years. This means half of the participants lived at least 23.4 years after their desmoid tumor treatment.

If left untreated, the median life expectancy with FAP is 42 years. This means that half of people with FAP live at least 42 years. If you’re living with FAP, it’s important to have regular checkups. Be sure to tell your doctor if you’re experiencing any desmoid tumor symptoms. Your doctor can run tests if they think you may have a desmoid tumor.

The Importance of Follow-Up Care

When living with desmoid tumors, it’s important to attend your follow-up appointments. These visits help your doctor monitor your disease so you can stay healthy. Some desmoid tumors return after treatment or grow larger. If they return to the same spot they were in before, it’s known as a local recurrence. Your doctor may perform more imaging tests to check for any new tumor growth.

If your desmoid tumor is progressing or has returned, your doctor may suggest trying another treatment option. Researchers continue looking for new ways to treat desmoid tumors. The U.S. Food and Drug Administration (FDA) recently approved nirogacestat (Ogsiveo) for treating desmoid tumors.

Clinical studies (studies that test the safety and effectiveness of drugs in people) have shown that nirogacestat improved PFS. This means that nirogacestat helped people live longer without disease progression or death. At this time, it’s not known if nirogacestat treatment affects life expectancy with desmoid tumors.

To learn more about treatments for desmoid tumor, talk with your doctor. They can help you manage your symptoms and boost your quality of life.

Talk With Others Who Understand

MyDesmoidTumorTeam is the social network for people with desmoid tumors and their loved ones. On MyDesmoidTumorTeam, members come together to ask questions, give advice, and share their stories with others who understand life with desmoid tumors.

Do you have other questions about how desmoid tumors affect life expectancy? Share them in the comments below, or start a conversation by posting on your Activities page.