Mammographic findings after breast conservation therapy.

Breast conservation therapy for breast cancer involves lumpectomy or segmental mastectomy followed by radiation therapy. Masses, fluid collections, architectural distortion, scarring, edema, skin thickening, and calcifications are posttreatment findings that may mimic or mask local tumor recurrence. Despite the overlap between posttreatment changes and tumor recurrence, the two entities can usually be distinguished by the characteristic mammographic appearances of posttreatment sequelae and by comparing interval findings on successive studies. Postoperative masses and fluid collections slowly diminish in size and usually resolve by 1 year after surgery. Radiation-induced edema gradually resolves; increasing edema may be due to recurrent cancer. Postsurgical scarring usually appears as a poorly marginated soft-tissue mass with interspersed radiolucent areas. Recurrent cancer is usually seen as a mass with no central radiolucent areas. Pleomorphic and granular microcalcifications are important markers for recurrent cancer and can usually be distinguished from the thick, calcified plaques and elongated dystrophic calcifications associated with scarring.