Desmoplastic small round cell tumors (DSRCT) are a rare and aggressive type of cancer. It primarily affects adolescents and young adults, typically arising in the abdomen and pelvis. It is aggressive and tends to spread early in its development.
Understanding Desmoplastic Small Round Cell Tumors
DSRCT is a soft tissue sarcoma, a cancer forming in connective tissues like fat, muscles, tendons, and blood vessels. These tumors are characterized by small, round cancer cells interspersed within a dense, fibrous, or “desmoplastic” stroma. While DSRCT most commonly originates in the lining of the abdomen and pelvis, known as the peritoneum, it can also appear in other areas.
DSRCT’s defining characteristic is the EWSR1-WT1 gene fusion. This fusion results from a translocation between chromosome 11 and chromosome 22, where parts of the EWSR1 gene on chromosome 22 incorrectly join with the WT1 gene on chromosome 11. This rearrangement creates an abnormal protein, contributing to uncontrolled cancer cell growth. This unique gene fusion confirms a DSRCT diagnosis.
DSRCT often spreads to other parts of the body, such as the liver, lungs, lymph nodes, and bones, even before symptoms appear. This early spread complicates treatment. DSRCT’s rarity, with only around 200 cases reported since 1989, presents challenges in research and clinical experience.
Recognizing Desmoplastic Small Round Cell Tumors
Early symptoms of DSRCT are often non-specific or absent, making recognition challenging. As tumors grow, symptoms may include abdominal pain, swelling, nausea, vomiting, diarrhea, or constipation. Unexplained weight loss and fatigue can also occur. These general symptoms make early diagnosis difficult.
Diagnosis typically involves imaging techniques. Doctors use ultrasound, computed tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans to identify tumor size, location, and spread.
Definitive diagnosis relies on a biopsy, taking a tissue sample from the tumor. A pathologist examines this sample under a microscope for characteristic small, round cells and dense desmoplastic stroma. Specialized molecular testing confirms the EWSR1-WT1 gene fusion. Techniques like fluorescence in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR) detect this unique genetic rearrangement. Molecular confirmation distinguishes DSRCT from other similar tumors.
Treatment Approaches for Desmoplastic Small Round Cell Tumors
Treatment for DSRCT involves a multidisciplinary approach due to its aggressive nature and tendency for widespread metastasis. As DSRCT is often advanced at diagnosis, treatment plans combine several therapies.
Intensive systemic chemotherapy is a primary component of treatment. This involves multi-agent regimens, including cyclophosphamide, doxorubicin, vincristine, ifosfamide, and etoposide. Chemotherapy aims to kill cancer cells throughout the body, especially when tumors are large or have spread. While DSRCT can be sensitive to chemotherapy, regimens are intense and may have side effects.
Aggressive surgical resection, or cytoreductive surgery, is another important aspect of treatment. Surgery aims to remove as much visible tumor as possible. As DSRCT often presents with numerous abdominal tumors, complete surgical removal can be complex and extensive.
In some cases, hyperthermic intraperitoneal chemotherapy (HIPEC) may be performed immediately after cytoreductive surgery. During HIPEC, heated chemotherapy drugs circulate directly within the abdominal cavity to target remaining microscopic cancer cells. This localized approach maximizes the drug’s effect on abdominal tumors, minimizing systemic side effects. HIPEC is an option for select patients, particularly those without disease spread outside the abdomen.
Radiation therapy is used to target residual cancer cells after surgery or manage specific tumor sites. This therapy uses high-energy beams to destroy cancer cells, delivered externally or internally. Whole-abdominal radiation therapy has been explored for DSRCT, though its use is limited by potential toxicity to healthy tissues.
Beyond conventional therapies, targeted therapies and clinical trials are increasingly important. Researchers investigate new agents targeting DSRCT’s genetic and molecular characteristics, like pathways activated by the EWSR1-WT1 fusion protein. Novel treatments offer hope for improving outcomes.
Living with Desmoplastic Small Round Cell Tumors
Living with DSRCT involves managing a rare, aggressive cancer, requiring ongoing monitoring and follow-up. Due to its tendency to recur, regular imaging tests, such as CT scans, are recommended every three to six months to check for new tumor growth. This surveillance helps detect recurrence early, allowing timely intervention.
Specialized cancer centers and multidisciplinary teams play a significant role in the long-term care of individuals with DSRCT. These teams, comprising surgeons, oncologists, radiation oncologists, and supportive care specialists, collaborate to provide comprehensive, individualized treatment. Integrated care addresses physical, emotional, and psychological needs of patients and caregivers.
Research and clinical trials continue to be important avenues for improving outcomes for those affected by DSRCT. Given its rarity, ongoing studies are vital for discovering more effective treatments. Participation in these trials offers access to innovative therapies and contributes to understanding the disease.