Breast Conservation Failure: When to Do a Completion Mastectomy

Anita Mamtani

Hiram S. Cody, III

Among all present-day patients presenting with breast cancer, breast conservation therapy (BCT) is suitable for 70% to 80%, is attempted in most of those eligible, and succeeds in about 90% of these cases (1). Ten-year rates of ipsilateral breast recurrence (IBTR) in contemporary randomized controlled trials (RCTs) which have included systemic therapy are low, 6% for node-negative and 9% for node-positive disease (Table 11-1) and trending lower (2,3,4). The “textbook” treatment for IBTR—both historically and by current NCCN guidelines (5)—has been mastectomy for all, but with advances in breast imaging, radiotherapy (RT), and systemic therapy this may no longer be the case. Since the topics of case selection for BCT, margin assessment, axillary management, local recurrence, oncoplasty, RT and reconstruction are covered in detail elsewhere (see Chapters 6, 7, 9, 10, 12, 20, 26, 33, 34, Sections 1–3), we will focus specifically on treatment strategies for failed BCT.

Declining Rate of Events

The first generation of RCTs comparing mastectomy with BCT demonstrated equivalent long-term survivals but higher rates of locoregional recurrence (LRR) for BCT (6,7). In more contemporary RCTs—including systemic adjuvant therapy—local control for BCT and mastectomy are equivalent (4), as are the rates of survival following IBTR (8). Further, a meta-analysis comprising 53 RCTs of adjuvant chemo- and hormonal therapy (1990 to 2011) demonstrates that the number of LRRs as a proportion of all breast cancer events is declining as well, from 30% to 15%, independent of the receipt of RT or type of surgery (9). Therefore, BCT makes sense as initial treatment whenever possible.

TABLE 11-1 Rates of IBTR and Post-IBTR Survival in NSABP Randomized Trials of BCT Including Systemic Therapy

Trial	10-Year IBTR (%)	5-Year Survival After IBTR (%)
NSABP Trials of Node-Negative Patients B-13, 14, 19, 20, 23 (2)	6	76
NSABP Trials of Node-Positive Patients B-15, 16, 18, 22, 25 (3)	9	60

Immediate Indications for Mastectomy

Some patients who appear suitable for BCT will have unexpectedly extensive disease—not apparent on preoperative imaging—on final pathology. Although one (or more) reexcisions can achieve negative margins in a most cases, persistently positive margins or deteriorating cosmesis are a clear indication for mastectomy. Some patients will have received neoadjuvant therapy in an effort to downstage a tumor otherwise unsuitable for BCT, and require mastectomy based on an inadequate response to treatment. Some patients will have predisposition on the basis of prior RT for lymphoma, a strong family history, or a deleterious gene mutation, and elect mastectomy to minimize the risk of second breast events. Finally, a few patients who are otherwise suitable for BCT in every way will elect mastectomy for reasons of their own.

Diagnosis and Workup of IBTR

Following successful BCT, routine follow-up typically comprises physical examination, annual mammography, and—for patients with heterogeneously dense breasts—screening ultrasound. In this setting, most IBTR will be small lesions detected by imaging and diagnosed by image-guided core biopsy. MRI makes sense whenever the extent of the lesion is unclear on conventional imaging, and for patients with larger lesions a metastatic workup is indicated to exclude distant metastases, which are present in as many as half of patients with invasive IBTR. Patients
with large or inflammatory IBTR may be candidates for downstaging by neoadjuvant therapy prior to surgery. Finally, as for patients who present initially with stage IV disease, most patients with coincident IBTR and distant metastases respond sufficiently well to systemic therapy that only a small minority will ever need surgery (10).

Treatment of IBTR

The Ipsilateral Breast: Mastectomy

Historically, the only option for the treatment of failed BCT—in the absence of distant metastases—was mastectomy, and this makes sense whenever dictated by the extent of the breast recurrence or by a significant cosmetic defect from the earlier BCT procedure. In this setting there is a range of options for breast reconstruction and plastic surgical consultation should be considered for all patients with IBTR. Mastectomy without reconstruction is absolutely reasonable for any patient who is opposed to reconstruction, who is uncertain whether to proceed (delayed reconstruction is almost always feasible), or who has medical contraindications. On the other hand, reconstruction makes sense for any patient who is certain, and in this setting an immediate reconstruction is suitable for most. Tissue expanders (TEs) have the advantage of simplicity and a satisfactory result in about two-thirds of carefully selected patients, but with a history of prior RT, TEs are associated with higher complication rates, including skin flap necrosis, infection, implant loss, limited expansion, and capsular contracture, compared to other methods (11,12). Latissimus flap reconstruction has the morbidity of a more extensive procedure, including that of the donor site, and requires an implant to restore volume, but is associated with fewer early wound complications and a lower rate of capsular contracture (13). Free flaps—most commonly from the abdomen (“deep inferior epigastric perforator [DIEP]”)—require the greatest expertise, the most extensive surgery, and entail the morbidity of a large abdominal donor site, but appear to offer the best long-term patient-reported outcomes, especially for patients with a history of prior RT (14,15,16).

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