Desmoplastic Small Round Cell Tumor (DSRCT) is a rare and aggressive cancer classified as a soft tissue sarcoma. It arises from the body’s connective tissues, like muscle and fat, and is characterized by small, round tumors seen under a microscope. These tumors most commonly develop within the abdominal or pelvic cavity on the tissue lining known as the peritoneum.
The tumors can grow quickly and may spread to nearby organs such as the liver, bladder, and colon. Due to its rarity, with only a few hundred cases documented since it was first identified in 1989, establishing a standard of care has been a challenge for the medical community.
Identifying DSRCT Sarcoma
The initial signs of DSRCT are often subtle and can be mistaken for other conditions. Many individuals do not experience symptoms until the tumors have grown to a significant size. A frequent first indicator is abdominal swelling or a hard, palpable mass in the abdomen, which may be accompanied by severe pain.
As the tumors grow and press on surrounding organs, other symptoms may develop. These can include changes in bowel habits, such as constipation or difficulty passing gas, and urinary issues. Some individuals may also experience nausea, vomiting, and a lack of appetite, which can lead to unexplained weight loss. These non-specific symptoms are often initially misdiagnosed.
The patient profile for DSRCT is specific. The cancer most commonly affects males, who are about four times more likely to be diagnosed than females. The age range is also narrow, with most cases occurring in adolescents and young adults between 10 and 30 years old. In rare instances when DSRCT occurs in females, its symptoms can be mistaken for ovarian cancer.
The Diagnostic Process
Confirming a DSRCT diagnosis involves a multi-step process. Healthcare providers start with a physical examination to feel for masses in the abdomen and take a detailed health history. Following this, imaging tests are ordered to visualize the abdomen and pelvis. Scans like Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and PET scans help locate tumors, determine their size, and assess if the cancer has spread.
While imaging provides a clear picture, a definitive diagnosis is made through a biopsy. This procedure involves taking a small tissue sample from a tumor for a pathologist to examine under a microscope. The cells of a DSRCT have a characteristic small, round appearance.
The most conclusive step is genetic testing on the tumor tissue. DSRCT is caused by a specific chromosomal mutation where the EWS gene fuses with the WT1 gene. This EWS-WT1 gene fusion is not an inherited trait but an acquired change that occurs during a person’s lifetime. Identifying this unique genetic marker allows pathologists to definitively distinguish DSRCT from other similar-looking cancers.
Multimodal Treatment Strategies
The treatment for DSRCT is complex, requiring a combination of different therapeutic approaches known as multimodal therapy. Because the tumors are often widespread at diagnosis, a single treatment method is insufficient. This combined strategy attacks the cancer from multiple angles to improve the chances of controlling the disease.
The first step is often intensive chemotherapy. Patients receive a powerful combination of several chemotherapy drugs, sometimes called the P6 protocol, to shrink the tumors before surgery. This initial phase of treatment is designed to make the subsequent surgery more effective by reducing the tumor burden.
Following chemotherapy, the next step is cytoreductive surgery. The objective of this extensive operation is to physically remove all visible tumors from the abdominal cavity. This surgery is often combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC), where heated chemotherapy drugs are washed through the abdomen to kill any remaining microscopic cancer cells.
Radiation therapy is another component of the comprehensive treatment plan. It uses high-energy x-rays to target and destroy any remaining cancer cells. This may involve delivering radiation to specific tumor sites or treating the entire abdomen. This multifaceted approach forms the foundation of treatment for this cancer.
Prognosis and Current Research
The outlook for individuals diagnosed with DSRCT is challenging, as it is an aggressive cancer. Survival rates have historically been low, with some studies indicating a five-year survival rate between 15% and 38%. The prognosis can be more favorable for patients whose tumors are localized and have not spread. However, the disease frequently returns after treatment has concluded.
Despite the difficult prognosis, ongoing research offers promise. Scientists are investigating new ways to combat DSRCT, with a focus on developing targeted therapies. These experimental treatments are designed to specifically attack the EWS-WT1 fusion protein, the underlying driver of the cancer, to stop the cancer cells from growing and dividing.
Clinical trials are underway to evaluate these novel targeted drugs, as well as other emerging treatments like immunotherapy. Immunotherapy aims to harness the body’s own immune system to recognize and fight cancer cells. Researchers are also exploring new chemotherapy combinations and refining surgical techniques. These efforts are a source of hope for developing more effective strategies.