Sarcoma is a type of cancer that develops in the bones or soft tissues like muscle, fat, blood vessels, or deep skin tissues. Sarcomas can occur at any age, but are most common in adults between the ages of 20-40 and children. There are over 50 different subtypes of sarcoma that are classified based on the type of cell or tissue they originate from. Some common types include:
- Osteosarcoma - Develops in the bones, usually around the knees, upper arms or thighs. It is the most common type of bone cancer.
- Ewing's sarcoma - A rare cancer that develops in bone or soft tissue, usually in the legs, arms, chest, pelvis or spine. It is more common in teenagers and young adults.
- Fibrosarcoma - Develops in fibrous connective tissues like tendons and ligaments. It can occur anywhere in the body.
- Liposarcoma - Originates in fat cells and is one of the most common types of soft tissue sarcoma. It usually develops in the thighs, hips or abdomen.
- Leiomyosarcoma - Develops in smooth muscle tissues like those found in the uterus, gastrointestinal tract or blood vessels.
- Rhabdomyosarcoma - A rare and aggressive cancer that develops in skeletal muscles during childhood and adolescence.
Sarcoma Symptoms
The symptoms of sarcoma vary depending on the location and size of the tumour but some common signs include:
- Painless swelling or lump - Sarcomas often presents as a painless swelling or lump that feels firm and may grow slowly over time.
- Bone pain - For bone sarcomas like osteosarcoma, the pain is usually worse at night or with activity and may be accompanied by swelling.
- Neurological symptoms - Sarcomas near nerves or the spinal cord can cause numbness, weakness or paralysis on one side of the body.
- Fatigue and weight loss - More advanced sarcomas can cause general fatigue, loss of appetite and unintentional weight loss.
- Fever - In rare cases, sarcoma may cause a fever if it is infected or has spread to other parts of the body.
Anyone experiencing persistent lumps, swelling, bone pain or other concerning symptoms should see their doctor for evaluation. Early detection greatly improves treatment outcomes for sarcoma.
Sarcoma Diagnosis
If a physical exam and patient history reveal concerning signs, the doctor will order tests to determine if the mass is cancerous and the specific type of sarcoma. This usually involves:
- Imaging tests - X-rays, CT scans or MRIs are used to examine the size, shape and location of the mass. They can also detect if it has spread.
- Biopsy - A small sample of the tumour is removed surgically and examined under a microscope by a pathologist. This is the only way to definitively diagnose sarcoma.
- Blood tests - Tests like a complete blood count and chemistry panel check for abnormalities that could indicate sarcoma or other health issues.
- Bone scan - Used if bone sarcoma is suspected to detect areas of abnormal bone activity throughout the skeleton.
- Genetic testing - Certain sarcoma subtypes have genetic risk factors that may be tested.
Staging the extent of the disease is also important for determining the appropriate treatment plan. Sarcomas are staged locally (tumour size/spread near site), regionally (spread to lymph nodes), or distantly (metastasized to other organs).
Sarcoma Treatment
A multidisciplinary team of surgeons, medical oncologists, and radiation oncologists will determine the best treatment options based on the type, stage and location of the sarcoma. The main treatment approaches are:
Surgery: Most sarcomas require surgery to remove the tumour. For some types, wide local excision may be sufficient but others may need more extensive surgery like limb salvage or amputation.
Chemotherapy: Powerful anti-cancer drugs are given systemically or directly into an artery to destroy any remaining sarcoma cells after surgery. It is also used for advanced or metastatic disease.
Radiation therapy: High-energy X-rays are used to kill cancer cells and shrink tumours. It may be given before or after surgery to further eliminate sarcoma cells.
Targeted drug therapy: For certain subtypes, newer targeted drugs that interfere with specific molecular pathways fueling cancer growth are being used.
A combination of these treatments gives the best chance of cure or long-term remission. Ongoing clinical trials also continue to improve sarcoma treatment outcomes. The prognosis depends on the stage, grade, and response to initial therapy.
Living with Sarcoma
For those in remission or with controlled disease, follow-up care involves regular medical exams and imaging to monitor for recurrence. A positive attitude and healthy lifestyle can help cope with the challenges of treatment and reduce cancer risk. Sarcoma survivors should know the signs of recurrence and report any new symptoms promptly to their doctor.
Support groups and counselling can help address emotional issues like fear, anxiety or depression. With early detection and multidisciplinary care, many sarcoma patients now have a good long-term prognosis. Advances in research also provide hope that more effective therapies will continue to emerge. With proper treatment and follow-up, living well with sarcoma is very possible.
Pathology and Histology of Sarcoma
When a biopsy sample is taken from a suspected sarcoma, it is examined under the microscope by a pathologist. The pathologist studies the appearance, structure and characteristics of the cells and tissues to determine the specific type of sarcoma.
Some key aspects they analyze include:
- Cell type - Identifying whether the cells originate from bone, fat, muscle or other connective/soft tissues helps classify the sarcoma subtype.
- Cell morphology - Features like cell shape, size, texture and internal structures provide clues about the cell lineage.
- Mitotic rate - Counting the number of actively dividing cells per area helps determine tumour grade and aggressiveness. Higher mitotic rates indicate faster growth.
- Necrosis - The presence of dead or degenerating cells in the tumour can indicate an advanced grade.
- Differentiation - Well-differentiated tumours resemble normal tissue cells more closely, while poorly differentiated cells have lost their normal appearance. Less differentiated sarcomas tend to have a worse prognosis.
- Invasiveness - How much the tumour cells have infiltrated surrounding tissues is also evaluated. More invasive sarcomas are higher grade.
Immunohistochemistry uses special stains on biopsy slides to highlight proteins expressed by the tumour cells. This helps identify specific markers that can confirm the sarcoma type. For example, rhabdomyosarcoma cells will stain positive for muscle markers.
Cytogenetic testing examines the tumour cells for any genetic abnormalities like translocations, amplifications or deletions. Certain chromosomal changes are diagnostic of particular sarcoma subtypes like Ewing's sarcoma or dermatofibrosarcoma protuberans.
By correlating the histologic appearance, immunostains and cytogenetics, the pathologist can provide a definitive diagnosis of the sarcoma subtype. This information guides prognosis and helps determine the most effective treatment approach.
Author
Dr. Maajid Mohi Ud Din Malik (M.Sc. Ph. D.)