Understanding Sarcoma: What to Know About Risks, Symptoms, and When to See a Doctor

Sarcoma refers to a broad group of cancers that start in the bones or in the tissue that connects, supports, and surrounds other body structures (soft tissue). Sarcomas account for about 15% of cancer diagnoses among children under the age of 20 and about 1% of adult cancer diagnoses.

Although sarcomas are rare, knowing the common symptoms and risk factors can help you feel more informed and confident when talking to your doctor.

Soft Tissue Sarcoma

Soft tissue sarcomas can grow in many parts of the body, including muscles, fat, tendons, nerves, blood vessels, and lymph tissue. There are more than 50 different types. In many cases, doctors don’t know exactly what causes them or how to prevent them. However, certain risk factors may increase your risk of developing soft tissue sarcoma:

• Previous radiation therapy for other cancers
• Cancer conditions that run in families, such as neurofibromatosis, Li-Fraumeni syndrome, retinoblastoma, and tuberous sclerosis
• Lymphedema (swelling due to fluid buildup) in the arms or legs for a long time
• Exposure to certain chemicals, such as vinyl chloride (used in plastics) and dioxin (most human exposure to dioxin is through meat and dairy products)
• Weakened immune system (such as HIV infection)

Common Symptoms

Sarcoma can often show up as a painless lump under the skin, usually on the arm or leg. If it starts in the belly (abdomen), you may not notice any symptoms until it gets larger and presses on nearby organs, nerves, or blood vessels, which may cause:

• Abdominal pain that gets worse
• Blood in vomit or stool
• Black, tarry stools

Bone Cancer

Bone cancer, also called osteosarcoma, typically affects the long bones in the arms or legs and is most common among children and young adults. Like soft tissue sarcoma, most cases of bone cancer happen without a clear cause; however, some things may increase your risk:

• Previous treatment with chemotherapy or radiation
• Genetic conditions, such as Li-Fraumeni syndrome, hereditary retinoblastoma, Rothmund-Thomson syndrome, Werner syndrome, Bloom syndrome, and Diamond-Blackfan anemia
• Paget disease of bone (more common in older adults)
• Changes in the RB1 gene, which is linked to some cancers

Although bone and soft tissue sarcomas are rare, staying alert to any unusual or ongoing symptoms, especially if you have known risk factors, is important. Many of the common signs of sarcoma are often caused by other conditions or injuries. But if symptoms don’t go away or worsen over time, don’t ignore them. Talking to your doctor early can make a big difference, leading to earlier treatment and better outcomes.