What Is DSRCT?

One thing to hold onto: rare does not mean alone. Take this at your own pace. There is a community that has walked this exact road, and you will find them at the end of this page.

Desmoplastic small round cell tumor (DSRCT) is an extremely rare and aggressive cancer. It is classified as a sarcoma, meaning it develops in the body's connective and supportive tissues. In most cases, DSRCT begins on the lining of the abdominal and pelvic cavity, and for many at diagnosis it may have already spread to nearby organs and lymph nodes.

DSRCT most often affects adolescents and young adults, and is significantly more common in males than females. Because it tends to grow silently in the abdomen, it is frequently diagnosed at an advanced stage.

Initial symptoms

DSRCT often fills in the spaces between organs and structures, and the early signs are ordinary enough to be mistaken for almost anything. Most people arrive at diagnosis after weeks or months of something that did not add up.

• Abdominal pain, or swelling and distension that keep getting worse
• Feeling full quickly, loss of appetite, or unexplained weight loss
• Nausea, vomiting, or a change in bowel habits
• Fatigue that does not lift with rest
• A mass that can be felt through the abdominal wall
• Fluid building up in the abdomen, called ascites

These are also the symptoms of far more common and far less serious conditions, and DSRCT tends to appear in people who are young and otherwise healthy. It is usually attributed to something else first. That is part of why diagnosis is so often delayed until the disease is advanced.

Presentation

Exactly where DSRCT originates from is still unknown, but it is often found in the omentum or the lining of the abdominal cavity. It frequently appears as many tumors (in some cases hundreds) scattered throughout the abdominal cavity and pelvis. Many also present with disease that has metastasized (spread) to the lymph nodes, liver or bones at diagnosis.

DSRCT was first identified and described in medical literature in 1989 by pathologists Gerald and Rosai. It is one of the youngest named cancers in oncology, which contributes to the limited overall research and disease information available.

Every case of DSRCT is defined by a specific chromosomal change: a fusion of two genes called EWSR1 and WT1. This is called the EWSR1-WT1 gene fusion, and it occurs on chromosomes 11 and 22.

This fusion acts like a switch stuck in the "on" position. It drives the body to overproduce proteins that push the tumor to grow and help it build its own blood supply. This single change is the engine of the disease, which is why so much DSRCT research aims directly at it. Finding the fusion is also how the diagnosis is confirmed.

The name of the disease reflects what it looks like in pathology: "desmoplastic" refers to the dense, fibrous tissue surrounding the tumor cells; "small round cell" describes the appearance of the cancer cells themselves.

DSRCT is confirmed with a biopsy, a small sample of tumor tissue that a pathologist examines. Under the microscope its cells look like small round blue cells, and several other cancers look much the same. That is why appearance alone is not enough. The diagnosis is only certain once a lab finds the EWSR1-WT1 fusion, the specific pairing of genes that defines the disease.

It is often called something else first

Because DSRCT is rare and looks so much like more familiar cancers, many patients are given another diagnosis before it is sorted out. Before DSRCT is confirmed, it is often first thought to be one of these:

• Ewing sarcoma
• Rhabdomyosarcoma
• Neuroblastoma
• Wilms tumor
• Lymphoma
• Small cell carcinoma

This is why the molecular test matters so much. It is the difference between a diagnosis that looks right and one that is right.

DSRCT is rare. That much is true. According to the NIH (National Institute of Health), DSRCT has an overall age-adjusted incidence rate of about 0.3 cases per million people.

You may have come across a number more specific - that there are only about 200 cases of DSRCT. That number is wrong, and it does real harm. It traces back to outdated reviews that looked at earlier SEER data. SEER is a national cancer registry that is still collecting information today; those reviews just came from a time when the tools to recognize this disease and the ways to treat it looked nothing like they do now. It was never an accurate count, and it has been repeated ever since. The reality is that far more than 200 people are diagnosed with DSRCT globally every year. In fact, its recorded incidence in the US has climbed roughly thirtyfold as recognition improved. The disease did not become more common. We got better at finding it.

There are no standardized treatment guidelines for DSRCT. Large clinical trials are hard to run for an ultra-rare cancer, because the patients are geographically scattered, which makes it difficult to bring enough of them into one study. Current treatment is guided by expert consensus and the published experience of high-volume sarcoma centers.

For most patients treatment is multimodal and aggressive, combining chemotherapy, surgery, and radiation rather than relying on any one of them. Research published in 2022 found that patients who received surgery combined with both chemotherapy and radiation had better survival outcomes than those who received surgery and chemotherapy alone.

Medications, doses, and timing vary from patient to patient. There is no one plan that fits all in DSRCT treatment. Our patient journey guide walks through what treatment actually involves, phase by phase, and our surgery guide covers the operation in depth.

DSRCT is an aggressive disease. Despite treatment, many patients will experience recurrence and far too many will ultimately die of this disease.

This is hard to sit with, and we do not want to minimize it. Much of what is known about outcomes reflects a time when less was understood about this disease and there were fewer drug options. Research is opening new directions that did not exist even a few years ago.

Long-term, disease-free survivors do exist, and most reached that through aggressive, multimodal treatment. While there is much opportunity to improve treatments and patient quality of life on treatment, and many people far outlive the expectations they were given at diagnosis.

DSRCT is considered a pediatric cancer, even though most patients are teenagers, young adults, or sometimes older adults. This can be confusing. The classification has nothing to do with the age of the patient. It has everything to do with the biology of the tumor.

Cancer type is determined by biology, not by who gets it

Adult cancers usually build up over decades, from accumulated damage and exposures. Pediatric cancers work differently. They tend to come from a single error early in development, one event that switches on genes that should have gone quiet. DSRCT fits that pattern almost entirely. It is driven by the one EWSR1-WT1 fusion, not by the pile-up of mutations behind adult cancers. So even when it turns up in a 35-year-old, the cancer is behaving like something that went wrong in early development, not something caused by decades of adult life.

Other cancers follow the same pattern

DSRCT is not unusual here. Ewing sarcoma, rhabdomyosarcoma, and medulloblastoma are all classified as pediatric even though they regularly appear in adults, because the biology of the tumor sets the category, not the age of the patient. Most DSRCT patients are diagnosed in their teens and twenties, though the range runs from childhood into the 50s and beyond. That range does not change what the tumor is.

A DSRCT diagnosis is rare enough that most oncologists will never see a case in their career. Talking to someone who has been through it is different from talking to someone who has only read about it.

The DSRCT Initiative hosts two ongoing virtual peer support groups for patients, caregivers, and those who have lost someone to this disease:

• ›
  An active-case peer support group for patients and caregivers currently navigating diagnosis or treatmentSign up for this group
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  A grief support group for those who have lost a loved one to DSRCTSign up for this group

The medical information on this page comes from published research and decades of lived experience within the DSRCT community. If you would like to see the specific studies behind it, they are all here.