Angiosarcoma, from the CureRays guide library.

Angiosarcoma is a rare, aggressive cancer of the cells that line blood and lymph vessels; treatment combines surgery, radiation, and chemotherapy, and it can arise in skin previously treated with radiation or in long-standing lymphedema.

What it is.

Angiosarcoma is a rare and aggressive cancer that develops from the cells lining blood vessels and lymph vessels — the channels that carry blood and lymph fluid through the body. Because these vessels run everywhere, angiosarcoma can arise almost anywhere, but it most often appears in the skin, particularly on the scalp and face of older adults, where it can look like a bruise that does not heal, a raised purple area, or swelling. It can also develop in the breast, liver, spleen, heart, or deep soft tissues. Two important situations deserve special mention: angiosarcoma can arise years after radiation therapy was given to an area for another cancer (for example, in the breast or chest wall after breast cancer treatment), and it can develop in an arm or leg affected by long-standing lymphedema — chronic swelling, often after lymph node surgery. Angiosarcoma tends to grow quickly, can spread to other parts of the body, and may involve a wide area of tissue with edges that are hard to define, which makes it challenging to treat. Because it is rare and complex, care is best delivered by a specialized sarcoma team. Treatment usually combines surgery to remove the tumor, radiation, and chemotherapy, tailored to where the cancer is and how far it has spread.

How radiation treats it.

Radiation therapy uses focused high-energy beams to damage the DNA inside cancer cells so they can no longer grow and divide. In angiosarcoma, radiation plays a major role because of one defining feature of this cancer: it often spreads microscopically far beyond what can be seen or felt, with edges that are difficult to define. This is especially true of angiosarcoma of the skin, such as on the scalp. As a result, even when a surgeon removes the visible tumor, cancer cells can remain in the surrounding tissue, leading to a high chance of the cancer coming back locally. Radiation addresses this by treating not just the tumor site but a generous surrounding area, catching hidden disease the eye and the scalpel can miss. It is most often given after surgery to lower the risk of return, but it can also be the primary treatment when a tumor cannot be removed or when a patient cannot undergo surgery, sometimes combined with chemotherapy to improve control. Because angiosarcoma frequently occurs in challenging locations — the curved surface of the scalp, the breast or chest wall (including areas that were irradiated years earlier for another cancer), or a swollen limb — careful planning matters. Modern techniques such as intensity-modulated radiation shape the dose around these complex areas, while electron beams can treat skin disease at a controlled depth, sparing deeper healthy tissue. Treating an area that has had previous radiation requires special expertise to balance effectiveness against the limits of tissue that has already received a dose. The radiation oncologist designs each plan to cover the wide area angiosarcoma puts at risk while protecting surrounding healthy tissue as much as possible.

The ways we can treat it.

Wide-field external-beam radiation. Because angiosarcoma — particularly of the skin — spreads microscopically beyond its visible edges, radiation often covers a generous area around the tumor to catch hidden disease, delivered with shaped beams to control the cancer while limiting harm to healthy tissue.

Radiation after surgery (adjuvant). Following removal, radiation treats the surgical bed and surrounding at-risk tissue to reduce the high chance of local recurrence that angiosarcoma carries.

Definitive radiation when surgery isn't possible. For tumors that cannot be removed or in patients who cannot have surgery, higher-dose radiation, sometimes combined with chemotherapy, is used to control the cancer.

Intensity-modulated and electron-beam techniques. Intensity-modulated radiation shapes the dose around complex areas like the scalp, while electron beams can treat skin disease at a controlled depth — both help cover broad at-risk areas while sparing deeper healthy tissue.

Questions we hear often.

Why does radiation cover such a large area? Angiosarcoma, especially in the skin, often extends microscopically well beyond what can be seen or felt, with edges that are hard to define. Treating only the visible tumor would leave hidden cancer behind, so radiation deliberately covers a generous surrounding area to catch those cells and reduce the high chance of the cancer returning locally.

Can angiosarcoma be caused by previous cancer treatment? In some cases, yes. A form of angiosarcoma can develop years after radiation was given to an area for another cancer, such as the breast or chest wall after breast cancer treatment. This is uncommon, but it is one reason any new bruise-like or non-healing change in a previously treated area should be checked promptly.

Why is care at a specialized center important? Angiosarcoma is rare, aggressive, and complex, with treatment that usually combines surgery, radiation, and chemotherapy in carefully coordinated sequence. An experienced sarcoma team is best equipped to plan this combination, handle challenging locations or previously irradiated tissue, and offer access to clinical trials.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.