What Are Desmoplastic Small Round Cell Tumors?

Desmoplastic small round cell tumors (DSRCT) are a type of rare, soft tissue sarcoma. This type of cancer usually begins in the abdomen or pelvis, and does not respond well to treatment. The majority of patients (90 percent) are Caucasian males between the ages of 10 and 30.

What Causes DSRCT?

Experts do not know what causes DSRCT; however, they believe a genetic abnormality involving chromosomes 11 and 22 may play a part in this cancer.

What Are the Signs and Symptoms of DSRCT?

DSRCT has few early warning signs. The cancer affects people who are otherwise healthy. The tumor can grow to a large size and coat the inside surface of the abdomen before a person notices it.

The main symptom of DSRCT is a solid mass in the abdomen. Other symptoms include:

• Belly cramps
• Continued belly pain
• Constipation
• Unexplained weight loss
• A painful lump in the belly button

DSRCT almost always begins in the abdomen. In more than 40 percent of patients, it can spread to the liver, lymph nodes, lungs, bones and other parts of the body.

How Common Is DSRCT?

DSRCT is a very rare cancer. Therefore, patients who have it should be treated at a comprehensive sarcoma center with experts in the field of radiation oncology, surgery and oncology who have experience and expertise in diagnosing and treating this disease.

How Is DSRCT Diagnosed?

A physical exam, biopsy and imaging tests are done to diagnose DSRCT. A small piece of the tumor is removed during a needle biopsy or surgical procedure. A specialist then examines the tissue under a microscope to check for DSRCT.

Imaging tests are done to find out the precise size and position of the tumor, and to see whether the cancer has spread.

Imaging tests might include:

• Magnetic resonance imaging (MRI)
• Computed tomography (CT)
• A chest CT
• Positron emission tomography (PET), a test that measures important body functions and also can show whether the cancer has spread

What Are the Stages of DSRCT?

Staging of DSRCT is based on the size of the tumor and whether it has spread to lymph nodes or distant sites in the body. If the tumor has not spread, it is considered to be localized. Metastatic DSRCT means the tumor has spread past nearby tissues to lungs or other organs.

How Is DSRCT Treated?

The doctor may recommend surgery to remove as much of the tumor(s) as possible. Because these tumors grow in and around other organs, it usually is not possible to remove the entire tumor this way. Most patients need to have other therapies after their surgery. The medical team may offer some or all of the following treatments:

• Traditional radiation therapy
• Proton therapy, which the doctor may recommend in special cases. Proton therapy is a type of radiation therapy that targets the tumor while avoiding organs and healthy tissue. This means fewer short-term and long-term side effects from radiation. Cincinnati Children’s is one of only a few pediatric hospitals in the country that offers proton therapy.
• High doses of chemotherapy to shrink the tumor(s) and prevent new ones from forming. This therapy may require the use of rescuing stem cells, which serve as an internal repair system for the body. Stem cell rescue involves removing stem cells from the blood between chemotherapy cycles and freezing them. After very high dose chemotherapy, the doctor thaws and injects the stem cells back into the body, where they begin forming new, healthy blood cells.
• A two-step surgical procedure called hyperthermic intra-peritoneal chemotherapy (HIPEC). This involves removing as much of the tumor as possible, then delivering highly concentrated, heated chemotherapy drugs directly to the abdominal area. This therapy is for patients whose cancer is located in the abdominal cavity.
• Maintenance therapy, which may be an option after an initial round of treatment. It can involve giving chemotherapy or “molecularly targeted therapy,” which uses drugs or other substances to interfere with specific molecules that allow cancer to grow and spread.
• One of several targeted tumor ablation techniques, which kill tumors

Doctors often schedule treatments as close together as possible to counteract the fast growth of DSRCT. Follow-up imaging tests can help monitor how the cancer is responding to treatment.

DSRCT often does not respond well to treatment. In some situations, the doctor may recommend participating in a clinical trial at Cincinnati Children's.

What Is Outlook for People with DSRCT?

DSRCT is unlikely to be cured in the majority of patients. However, complete surgical resection by an experienced sarcoma surgeon has been shown to improve time to relapse and potentially provide cure in a subset of patients.