The risk of in-breast recurrence (IBR) after mastectomy is approximately 4.9% at 5 years (3). This is independent of whether the mastectomy is done as a skin-sparing mastectomy (SSM) or nipple-sparing mastectomy (NSM). The median time for the appearance of clinically overt local recurrence (LR) is 2 to 4 years, depending on stage. Most recurrences occur on the skin/subcutaneous tissue not the muscle. Unfortunately, LR after mastectomy is rarely an isolated event with most eventually developing metastatic disease. Failure of mastectomy to prevent IBR may be related to the minimal yet irreducible percentage of residual breast tissue and lymphatics either in the skin flaps, or chest wall. Additional breast tissue can be found outside the confines of the mastectomy—above the clavicle, within the axilla, posterior to the anterior axillary line, and extending down on the abdominal wall through the inframammary fold.

An LR after breast-conserving surgery (BCS) may present in several different ways. Patients most commonly present with a new palpable mass or area of thickening in the breast or a new mass in the axilla. They may also present with small superficial skin nodules, measuring from 3 to 5 mm on the chest wall or an area of retraction in the skin or nipple. Patients may also be asymptomatic with only mammographic or sonographic evidence of malignancy (i.e., areas of architectural distortion, new microcalcifications, or masses). Tragically, patients can present with fungating masses in the area of a previous lumpectomy (Fig. 20-2). Patients who have undergone mastectomy with autologous reconstruction may also present in similar fashion with a palpable mass, skin nodules, areas of retraction, or new skin erythema. The differential diagnosis in this patient population can include the development of a recurrence, progressive fat necrosis, a chronic seroma, scar tissue, fibrocystic change, breast edema, and
idiopathic postmastectomy vasculitis (Fig. 20-3). Biopsy of the mass or skin lesion is critical to determine the nature of the lesion.

In terms of timing, an LR, RR, or secondary primary tumor can occur at any time after treatment. Patients with an LR or RR have a significantly higher risk of developing distant disease and poorer overall survival as compared to those without an LR or RR. Geurts et al. reviewed the nationwide population-based Netherlands Cancer Registry cohort of women who were treated with curative intent for breast cancer (4). They analyzed the occurrence and timing of both the first recurrence and subsequent recurrences in 9,342 patients. They also identified prognostic factors for both first and subsequent recurrences. Lastly, they identified consequence of these patterns for
surveillance. Recurrence occurred in 1,853 women (20%). A total of 1,343 (72%) patients first presented with a distal recurrence while 362 (20%) had LR and 148 (8%) had an RR. Subsequent recurrences were also most commonly distant (Fig. 20-4). They identified that most commonly patients locally recur during the second year after treatment. RR and distant recurrences rates remain relatively constant through 10 years of follow-up (Fig. 20-5A). The annual risk of LR peaked at 2 years (0.7% [95% CI 0.5 to 0.8]) and 8 years (0.4% [95% CI 0.2 to 0.5]). The annual risk of RR peaked at 2 years (0.3% [95% CI 0.2 to 0.4]) and then decline thereafter (Fig. 20-5B).