Angiosarcoma is a cancer originating in the cells that line blood vessels and lymphatic vessels. It can develop anywhere but is most often found in the skin, breast, liver, and spleen. This cancer is aggressive and grows quickly. The tumors often appear as a bruised, purplish area on the skin that may grow over time and can bleed easily if bumped or scratched.
Angiosarcoma Incidence Rates
Angiosarcoma is exceptionally rare, diagnosed in approximately one to two people per million each year in the United States and Europe. It accounts for only 1% to 2% of all soft tissue sarcomas, which are themselves an uncommon category of cancer.
Approximately 60% of all cases are cutaneous, developing in the skin. The scalp is a particularly common location for these skin-based tumors, accounting for about 50% of cutaneous angiosarcomas. This still represents less than 0.1% of all head and neck tumors.
The cancer is also found in soft tissues, the breast, and the liver. Primary breast angiosarcoma, not linked to prior radiation, is rare, making up just 0.04% of all breast tumors. Angiosarcoma of the liver accounts for only 0.1–2.0% of all primary liver cancers. The incidence is higher in older adults, with a median diagnosis age of around 70, although it can occur at any age.
Associated Risk Factors and Demographics
One of the most well-documented risk factors is chronic lymphedema, a condition of persistent swelling caused by a compromised lymphatic system. This is seen in Stewart-Treves syndrome, where angiosarcoma develops in the arm of a patient who has undergone a radical mastectomy for breast cancer that included the removal of axillary lymph nodes.
Previous exposure to radiation therapy for other cancers is another risk factor. Radiation-associated angiosarcoma can develop in the treatment field years after therapy is completed, most frequently in women treated with radiation for breast cancer. The latency period can be as long as 23 years, and the cumulative incidence after breast radiation therapy is estimated to reach 1.4% after 20 years.
Exposure to certain industrial chemicals is also linked to an increased risk, though these scenarios are less common today. Vinyl chloride, a chemical used in the plastics industry, is a known carcinogen associated with hepatic angiosarcoma. Arsenic, once used in insecticides, has also been identified as a risk factor.
Demographically, cutaneous angiosarcoma of the head and neck predominantly affects older, fair-skinned adults, with a mean age of 73 years, and is more common in men. Its appearance on the scalp and face in this population suggests that long-term sun exposure and ultraviolet radiation may play a role in its development.
Prognosis and Survival Statistics
The prognosis for angiosarcoma is challenging due to its aggressive behavior and tendency to be diagnosed at a late stage, often after it has already spread. This results in a worse prognosis. The cancer cells can spread quickly through blood or lymph vessels to distant sites, most commonly the lungs and liver.
Overall five-year survival rates are between 20% and 40%, but these statistics vary based on several factors. The stage at diagnosis is a primary determinant; the 5-year survival rate for localized angiosarcoma can be as high as 81%. This rate drops to around 15% if the cancer has spread to distant parts of the body.
The location of the primary tumor also influences the outcome. Cutaneous tumors, especially small and superficial ones, may have a better prognosis than tumors deep within soft tissues or organs like the liver or heart. For instance, the median survival for visceral or deep soft tissue angiosarcoma can be as low as five months, while it can exceed 60 months for localized disease. Tumor size is another factor, with tumors larger than 5 cm being associated with a poorer outlook.