Sarcoma is a type of cancer that starts in connective tissues, the structural materials that hold your body together. Unlike the more common carcinomas, which develop in organs and glands, sarcomas grow in bone, cartilage, fat, muscle, blood vessels, nerves, and other supportive tissues. They account for only 1 to 2% of adult cancers, though they make up a larger share in children and young adults, representing 6 to 15% of cancers diagnosed before age 15.
Where Sarcomas Develop
Sarcomas fall into two broad categories based on where they start: soft tissue and bone. Soft tissue sarcomas are the more common group, with over 60 distinct subtypes that can form virtually anywhere in the body. They arise from fat, muscle, nerves, blood vessels, and the fibrous tissue that surrounds joints and organs. Bone sarcomas are less common and grow within the skeleton itself.
The most frequently diagnosed soft tissue sarcomas include liposarcoma (from fat cells), leiomyosarcoma (from smooth muscle, the type found in your uterus, stomach, and blood vessel walls), and undifferentiated pleomorphic sarcoma (a catch-all term for aggressive tumors that no longer resemble a specific tissue type). The main bone sarcomas are osteosarcoma, chondrosarcoma, and Ewing sarcoma. Each behaves differently, tends to appear at different ages, and responds to different treatments.
Bone Sarcomas and Who Gets Them
Osteosarcoma is the most common primary bone cancer. In young people, it typically develops near the ends of long bones during periods of rapid growth, especially around the knee (the lower thighbone or upper shinbone) and the upper arm. In adults, osteosarcoma more often appears in the spine or pelvis and is sometimes linked to prior radiation treatment or existing bone disease.
Chondrosarcoma forms in cartilage cells. It most often affects the long bones of the arms and legs but can also develop in flat bones like the pelvis, ribs, and shoulder blade. It tends to be a disease of middle-aged and older adults.
Ewing sarcoma stands apart because it usually strikes children and teenagers. It characteristically grows in the middle shaft of long bones rather than near the ends, and frequently involves the leg bones, pelvis, ribs, and spine.
Symptoms to Recognize
Soft tissue sarcomas often first appear as a painless lump. Because these lumps can grow deep beneath the skin, they may reach a significant size before anyone notices. Clinical guidelines flag a soft tissue mass for urgent evaluation if it is larger than 4 to 5 centimeters (roughly the size of a golf ball), is increasing in size, sits deep within the muscle rather than just under the skin, is painful, or has come back after being previously removed.
Bone sarcomas tend to announce themselves differently. The hallmark symptom is bone pain that intensifies over time, is not clearly tied to physical activity, and may wake you at night. Swelling or tenderness over the bone, difficulty using the affected limb, an unexplained limp, or a fracture that occurs without a clear injury are all warning signs. Because bone pain is common and usually caused by something benign, these cancers are sometimes initially mistaken for growing pains in teenagers or arthritis in adults.
Known Risk Factors
Most sarcomas develop without an identifiable cause, but a few risk factors are well established. Prior radiation therapy is one of the clearest. The risk increases in a dose-dependent way, particularly after high-dose radiation (above 10 Gy) received in childhood, and continues to climb with higher doses up to about 40 Gy. Long-term follow-up of Japanese atomic bomb survivors has also shown that even lower acute radiation doses can raise sarcoma risk at any age.
Several rare inherited genetic conditions significantly increase susceptibility. Li-Fraumeni syndrome, caused by mutations in a key tumor-suppressing gene, is one of the strongest links. In studies of Li-Fraumeni families, half of second sarcomas appeared in areas that had previously been treated with radiation, suggesting these individuals are especially sensitive to radiation’s effects. Other predisposing conditions include neurofibromatosis type 1, retinoblastoma, Werner syndrome, and familial gastrointestinal stromal tumor (GIST) syndrome. These genetic conditions are rare, though, and the vast majority of people diagnosed with sarcoma have no family history of the disease.
How Sarcoma Is Diagnosed
Diagnosis typically begins with imaging. MRI is the preferred tool for soft tissue masses because it shows the tumor’s relationship to surrounding muscles, nerves, and blood vessels in fine detail. CT scans and PET scans are also used, particularly to check whether the cancer has spread to the lungs or other distant sites.
Imaging alone cannot confirm a sarcoma. The gold standard for diagnosis is a biopsy, in which a small tissue sample is removed and examined under a microscope by a pathologist. This step is critical not just for confirming cancer but for identifying the specific subtype, which directly shapes the treatment plan. Many sarcoma centers now also perform genetic and molecular sequencing on the tumor to further refine the diagnosis and identify potential treatment targets.
Getting the biopsy right matters more than you might expect. An improperly placed biopsy can contaminate surrounding tissue and limit future surgical options. This is one reason specialists strongly recommend that biopsies be performed at or coordinated with a center experienced in sarcoma care.
Treatment Options
Surgery is the foundation of sarcoma treatment. The goal is to remove the entire tumor along with a margin of healthy tissue around it, while preserving as much function as possible. For tumors in the arms or legs, modern approaches combine surgery with radiation therapy to spare the limb. Amputation, once common, is now a last resort.
Radiation therapy is frequently used before or after surgery to reduce the chance of the cancer returning at the original site. When given before surgery, radiation fields and doses are generally smaller, which limits side effects. In rare situations where surgery would cause unacceptable damage to nearby organs or structures, radiation may serve as the primary treatment on its own.
Chemotherapy plays a more defined role in certain subtypes than others. It is a standard part of treatment for Ewing sarcoma and some high-grade bone sarcomas, but its benefit in most soft tissue sarcomas remains less clear. When chemotherapy is used for advanced or metastatic soft tissue sarcoma, a class of drugs called anthracyclines is typically the first choice. In clinical studies, chemotherapy given before surgery has produced tumor shrinkage in 17 to 32% of patients, with long-term survival rates reaching up to 64% at ten years in some trials.
Survival and Prognosis
Outcomes depend heavily on how far the cancer has spread at diagnosis. For soft tissue sarcomas that are still localized, meaning confined to the area where they started, the five-year relative survival rate is 83%. That number drops sharply to 17% when the cancer has spread to distant sites like the lungs. These figures, based on patients diagnosed between 2015 and 2021, underscore why early detection and proper initial management carry real consequences.
The specific subtype also matters. Low-grade sarcomas grow slowly and rarely spread, while high-grade tumors are more aggressive and more likely to metastasize. Tumor size, depth, and location all factor into the overall picture.
Why Specialized Care Matters
Sarcomas are rare enough that many general surgeons and oncologists encounter only a handful of cases over their careers. This rarity creates a real risk of misdiagnosis or suboptimal initial surgery. Studies have found that a large proportion of soft tissue sarcoma patients who first undergo surgery outside a specialized center end up needing more extensive follow-up surgery and radiation than the original tumor would have required. In some cases, poorly planned initial surgery has led to unnecessary amputations.
Specialized sarcoma centers bring together surgeons, oncologists, radiologists, and pathologists who work with these tumors routinely. A multidisciplinary team approach ensures the biopsy is done correctly, imaging is interpreted by radiologists familiar with sarcoma patterns, and treatment is planned with all available options on the table. For patients with bone sarcomas, these centers also coordinate rehabilitation with specialists who understand the unique recovery challenges of younger patients returning to work and daily life.