An overview on sarcomas – A diverse group of rare cancer

Sarcomas are a diverse group of rare cancers that arise from mesenchymal cells, which are found in connective tissues throughout the body. They can develop in bones (osseous sarcomas) or soft tissues (soft tissue sarcomas), each with distinct characteristics and management approaches. This discussion will focus primarily on soft tissue sarcomas (STS)

Types and Classification: Soft tissue sarcomas encompass over 50 histological sub types, each with unique biological behaviours and clinical implications

Common types include:
• Leiomyosarcoma: Arises from smooth muscle cells, commonly found in the uterus, gastrointestinal tract, or blood vessels.
• Liposarcoma – Originates in fat cells, most often occurring in the limbs or retro peritoneum.
• Undifferentiated Pleomorphic Sarcoma (UPS) – Formerly known as malignant fibrous histiocytoma, UPS is a high-grade tumour with no specific tissue differentiation.
• Synovial Sarcoma – Typically affects joints, tendons, or bursae, often in young adults.
• Rhabdomyosarcoma – Primarily found in children and adolescents, arising from skeletal muscle cells.
• Fibrosarcoma – Arises from fibroblasts, commonly found in deep soft tissues.
• Bone sarcomas – These are rare cancers that develop from cells of the bone. They primarily affect children, adolescents, and young adults but can occur at any age. The two main types are osteosarcoma and Ewing sarcoma.
• Osteosarcoma – Arises from bone-forming cells and often occurs in the long bones of the arms and legs, particularly around the knee. It is the most common primary bone cancer and typically affects adolescents during growth spurts.
• Ewing Sarcoma – Arises from primitive nerve tissue in bone marrow and mainly affects children and young adults. It commonly arises in the pelvis, thigh bones, ribs, and upper arms.

Epidemiology and Risk Factors – Soft tissue sarcomas are rare, accounting for less than 1% of adult malignancies. They can occur at any age but typically affect adults in their 50s-60s.
• Risk factors include genetic predispositions (e.g., Li-Fraumeni syndrome, neurofibromatosis type 1), prior radiation therapy, and certain environmental exposures (e.g., chemicals like vinyl chloride).

Clinical Presentation – Soft tissue sarcomas often present as painless masses or swelling, which may grow rapidly or remain stable for extended periods. Symptoms depend on the tumour’s location and size, potentially causing pain or functional impairment as they enlarge and compress adjacent structures.

Diagnosis and Staging – Diagnosis involves imaging studies such as MRI or CT scans to assess tumour size, location, and involvement of nearby structures. Definitive diagnosis requires biopsy, typically performed with a core needle or through surgical excision, to obtain tissue for histopathological examination. Staging determines the extent of disease spread, guiding treatment decisions.

Treatment Strategies- Management of soft tissue sarcomas is complex and requires a multidisciplinary approach involving surgical oncologists, medical oncologists, radiation oncologists, and pathologists.
• Surgery- Primary treatment aims for complete surgical resection with negative margins to achieve local control. Limb-sparing techniques are preferred to preserve function whenever possible
• Radiation therapy- Used as adjuvant therapy post-operatively to reduce local recurrence risk or pre-operatively to shrink tumours and facilitate surgical resection.
• Chemotherapy- Certain sub types (e.g., high-grade sarcomas) benefit from chemotherapy to control micro-metastatic disease or shrink tumours before surgery.
• Targeted Therapy and Immunotherapy- Emerging treatments like tyrosine kinase inhibitors (e.g., pazopanib) & immunotherapies (e.g., checkpoint inhibitors) are being explored in clinical trials for specific subtypes resistant to conventional therapies.
• Prognosis- Prognosis varies widely depending on tumour sub type, grade, stage at diagnosis, and treatment response. Localized tumours have better outcomes than those with metastasis. Long-term surveillance is crucial due to the risk of recurrence, which can occur years after initial treatment.

Conclusion – Soft tissue sarcomas present significant challenges due to their rarity, histological diversity, and complex treatment algorithms. Advances in understanding tumour biology and treatment modalities continue to improve outcomes, emphasizing the importance of personalized, multidisciplinary care to optimize survival and quality of life for patients with these challenging malignancies.

 

This article is written by Dr. Neelesh Reddy, Consultant – Medical Oncologist, Manipal Hospital Yeshwanthpur