Mammography is an essential tool for monitoring conservatively treated breast cancer patients. Recognizing the distinctions between mammo-graphic appearance of the expected postsurgical, postradiation developments and that of recurrent carcinoma is critical for patient care.
Magnification mammography is useful after surgery to ensure complete excision of the malignant lesion. If the targeted lesion and all tumor-related calcifications are not clearly included on the specimen radiograph, or if there is discordance between the pathology results and the preoperative diagnosis, magnifications mammography can reveal the retained primary lesion or residual malignant calcifications. Postoperative magnification mammogra-phy is useful prior to radiation to ensure complete excision of the calcium-containing tumor. Unfortunately, mammography cannot definitively predict the histologic extent of tumors.
Mammography performed within the first few weeks after tumorectomy is often limited by the patient's discomfort, breast edema, post-surgical architectural distortion, and the presence of postoperative fluid collections (ie, seromas and hematomas) (Figure 3-27A). Postexcision changes frequently result in increased density that can obscure subtle residual malignant calcifications (Figure 3-27B).
Although these alterations regress and stabilize with time, they are accentuated and prolonged by subsequent radiation therapy.30,31
Mammography is important for long-term monitoring to evaluate for recurrent disease or new lesions in either breast. This should commence with a post-treatment baseline mammogram being performed within 3 to 9 months following tumor excision and completion of radiation therapy. Standard views may be supplemented with special projections to fully define post-therapy changes. Magnification mammography is particularly important when evaluating the breast for retained or recurrent malignant microcalcifications. Subsequent annual or more frequent mammograms should be obtained as indicated by clinical or radiographic evaluation. Comparison of the post-treatment mammo-grams to preceding studies is necessary to accurately assess radiographic changes following completion of therapy. Among the most common post-therapy changes are breast edema, skin thickening, postoperative fluid collections, scarring, fat necrosis, and calcifications.
The mammographic findings of skin thickening, irregular breast parenchyma, and breast edema following surgery and radiation are most prominent on the post-treatment baseline study and typically diminish over 2 to 3 years following conservative therapy.3032 Once mammo-graphic stability of the breast has been established, any increase in the architectural distortion or enlargement of the dense scar at the surgical site suggests the presence of recurrent tumor. Interrupted lymphatic drainage after extensive axillary node dissection may produce chronic breast edema. Recurrent edema with erythema may be a manifestation of infection (mastitis), inflammatory breast carcinoma, or recurrent breast cancer with lymphatic involvement. Postoperative fluid collections, such as hematomas or seromas at the lumpectomy site, present mammographically as high-density oval masses that may have ill-defined or spiculated margins (see Figure 3-27). These diminish in size as the fluid is resorbed over a period of 6 to 18 months.3031 If the fluid collection is enlarging or an abscess is suspected, ultrasonography can be used to evaluate the process further and to guide diagnostic needle aspiration.
Coarse, benign, dystrophic calcifications can develop several years after radiation and surgery. These calcifications frequently represent fat necrosis or occasionally calcified suture material in the surgical bed. Sometimes the developing benign calcifications have an indeterminate appearance necessitating tissue sampling. Occasionally fat necrosis can present as an irregular mass-like lesion that may simulate tumor recurrence.
The mammographic indications of tumor recurrence at the surgical site frequently develop between 2 to 3 years following conservative breast surgery.33 The development of increased
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