The use of whole-breast irradiation to treat stage I and II breast cancer appears to be increasing the incidence of radiation-associated angiosarcoma (RAS) of the breast, and radiologists play a crucial role in diagnosing the disease, four Harvard-affiliated radiologists write in a discussion piece published ahead of print in the American Journal of Roentgenology.
Lead-authored by Allyson Chesebro, MD, of Dana-Farber Cancer Institute and Brigham and Women’s Hospital, the article points out that RAS is rare but, once established, aggressive.
It often first appears five to seven years after radiation therapy as swelling, rash, discoloration or thickening of the skin.
“Increased use of breast conservation therapy (BCT), consisting of lumpectomy and whole-breast irradiation … appears to have increased the frequency of RAS, reported as 0.04 to 0.16 percent and as high as 0.3 percent,” write Chesebro et al. “Because its appearance can mimic bruising and appear benign, the diagnosis of RAS is often delayed.”
They state that conventional breast imaging, including mammography and ultrasound, is not as sensitive as MRI for the detection of RAS.
“Radiologists must carefully review all examinations obtained after BCT for increasing skin thickening, which may be the only sign of RAS on mammography or ultrasound,” the authors write, adding that MRI shows skin enhancement, thickening, edema and, sometimes, parenchymal masses.
RAS treatment includes mastectomy with removal of all irradiated skin to decrease the risk of local recurrence.
“Despite treatment, the prognosis remains poor,” they write. “Metastases usually spread hematogenously, with the lungs being the most common site.”
Chesebro and colleagues maintain that radiologists play a key role in the follow-up of patients with and treated for RAS.
They strongly recommend CT for monitoring response to treatment and for identifying early signs of local recurrence or distant metastases.
“When evaluating patients with breast cancer who have been treated with breast irradiation,” the authors conclude, “the radiologist must remember RAS as a complication of radiation therapy that can manifest many years after initial treatment.”