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Decision Making in the Surgical Management of Invasive Breast Cancer—Part 1: Lumpectomy, Mastectomy, and Contralateral Prophylactic Mastectomy

Decision Making in the Surgical Management of Invasive Breast Cancer—Part 1: Lumpectomy, Mastectomy, and Contralateral Prophylactic Mastectomy

Oncology (Williston Park). 31(5):359-368.
Table 1. Randomized Trials Comparing Mastectomy and Breast-Conserving ...
Table 2. Studies Evaluating the Role of MRI in Patients With Newly Dia...
Table 3. Evaluating the Role of Breast MRI in Patients With Newly Diag...

Several prospective randomized clinical trials conducted internationally have proven the safety and survival equivalence of breast-conserving surgery compared with mastectomy. Adjuvant radiation is routinely recommended following lumpectomy surgery to minimize the risk of local recurrence. Comprehensive breast imaging (including bilateral mammography with diagnostic views and ultrasound evaluation), in addition to clinical examination, is essential to rule out potential contralateral pathology and to optimally characterize the extent of disease. These studies are considered standard in the assessment of patient eligibility for lumpectomy. MRI of the breast remains controversial as an adjunct to determine candidacy for breast conservation, since MRI findings increase mastectomy rates without evidence of improved local control; prospective randomized clinical trials are underway to define the role of MRI in newly diagnosed breast cancer. Recently, the multidisciplinary oncology community has adopted a consensus guideline defining “no ink on tumor” as an acceptable microscopic margin at lumpectomy; however, post-lumpectomy imaging may be necessary to confirm complete removal of all cancer-associated microcalcifications, with clinical judgment exercised regarding re-excision for close margins. Contralateral prophylactic mastectomy is becoming increasingly common in the United States, and patients considering this option must be counseled about its lack of a survival benefit, its higher complication rate, and the fact that it is risk-reducing but not risk-eliminating.

General Concepts in Primary Management of Invasive Breast Cancer

Multiple international randomized clinical trials conducted between 1961 and 1989 confirmed the equivalence of overall survival outcomes between breast-conserving surgery and mastectomy for operable breast cancer (Table 1).[1-9] As shown by the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-06 trial, adjuvant radiation therapy (RT) does not have a significant impact on overall survival, but it reduces the risk of in-breast recurrence substantially.[1] Lumpectomy followed by contemporary whole-breast RT (WBRT) is associated with an average annual risk of subsequent in-breast cancer events ranging from 0.3% to 1%, and at 5 years local recurrences are therefore observed in 2% to 5% of cases. During the first 5 to 10 years of follow-up, most of these in-breast events are true local recurrences; the ongoing cumulatively increasing risks represent the progressively rising likelihood of developing a new primary breast cancer. Patients with hereditary susceptibility to breast cancer as a consequence of harboring a BRCA1 or BRCA2 mutation may have a risk of new primary breast cancer as high as 2% to 5% per year.[10,11] The chemoprevention and local control benefits conferred by the use of adjuvant endocrine therapies reduce the risk of new primary breast cancer by 50% for patients treated with tamoxifen, and by 70% for patients who receive treatment with aromatase inhibitors.[12] Notably, however, endocrine therapies only reduce the risks associated with hormone receptor (HR)-positive breast cancer, and carriers of BRCA1 mutations are at increased risk for developing triple-negative breast cancers (TNBCs; tumors that are negative for the estrogen receptor, the progesterone receptor, and human epidermal growth factor receptor 2), for which endocrine therapies are ineffective.

As shown in Table 1, several of the prospective randomized trials demonstrated rates of ipsilateral breast cancer events that were twofold to fourfold higher following lumpectomy and radiation, compared with the rates of chest wall failure following mastectomy. In general, local recurrence after mastectomy is perceived as being an indicator of biologically aggressive disease, and a harbinger of distant organ failure. In contemporary breast cancer management, patients who present with clinical features suggesting increased risk of chest wall recurrence are recommended to receive postmastectomy RT. Chest wall failures at 10 years are observed in more than 20% to 30% of patients with at least four metastatic axillary nodes, node-positive T3 disease, inflammatory breast cancer, and/or residual axillary metastases following neoadjuvant chemotherapy. Postmastectomy RT can reduce these rates by more than 50% and therefore is routinely recommended in these scenarios. Benefits of postmastectomy RT are less well defined in T1/T2 breast cancer associated with one to three positive axillary nodes, T3/node-negative breast cancer, and in patients presenting with axillary node–positive disease that is downstaged to node negativity by neoadjuvant chemotherapy.[13]

Along with improvements in surgical management of the breast in patients with cancer, surgical management of the axilla has evolved significantly, with less invasive approaches available in select patient populations. Lymphatic mapping with sentinel lymph node (SLN) biopsy has emerged as the preferred strategy for assessing nodal status.[14] Plastic surgeons have developed a broad array of reconstruction options for mastectomy patients, as well as techniques to restore symmetry in selected patients who have undergone lumpectomy with or without RT. Multidisciplinary breast oncology in the 21st century combines the expertise of breast imaging specialists; pathologists; and medical, surgical, and radiation oncologists to offer optimized systemic therapy and surgical management with the least disfigurement.

Potential Advantages of Breast-Conserving Surgery vs Mastectomy

Multiple studies have documented rising rates of mastectomy in the United States among breast cancer patients who are candidates for lumpectomy; there has also been an increase in the number of patients undergoing contralateral prophylactic mastectomy (CPM), despite the lack of definitive evidence that this procedure confers a survival advantage.[15] Patient choice must be respected as an essential element of quality of life; however, given these changing patterns of care, surgeons must carefully communicate to the individual patient all of the appropriatebreast cancer treatment options and confirm that they are understood.[16,17] Indeed, breast-conserving surgery generates definitive staging information without “burning any bridges” and has other advantages compared with a potentially premature decision to pursue mastectomy.

For example, lumpectomy in conjunction with axillary surgery as the initial treatment plan provides the patient and multidisciplinary team with definitive histopathologic information regarding the primary tumor and lymph nodes. The status of the axillary lymph nodes in particular can have a significant downstream impact on other surgical treatment decisions. Patients who undergo lumpectomy and are shown to have metastatic disease in one or two SLNs can usually be spared from undergoing a completion axillary lymph node dissection (ALND). Results from the American College of Surgeons Oncology Group Z0011 trial demonstrated that completion ALND provides no advantage in clinical outcomes to such patients,[18] with observed equivalence of locoregional control likely related to adjuvant irradiation of the lower (undissected) nodal basin of the breast. In contrast, patients for whom mastectomy is planned usually do require completion ALND if SLN metastases are present, since knowing the fully quantified extent of nodal metastatic disease will enable clinicians to determine whether RT will be necessary following mastectomy.[14] Furthermore, node-positive mastectomy patients are often discouraged from pursuing immediate breast reconstruction because some plastic surgeons are unwilling to accept the risk of potential irreversible damage to the reconstructed breast caused by postmastectomy radiation.

Therefore, performing an initial lumpectomy and SLN biopsy preserves more options, namely:

• Patients found to be node-negative can pursue mastectomy (if strongly desired) and immediate reconstruction free of concerns regarding postmastectomy RT.

• As described previously, patients with limited nodal metastases can avoid completion ALND and need not face the prospect of mastectomy without immediate reconstruction.

• Mastectomy with immediate reconstruction remains an option as elective prophylactic surgery following completion of the acute multimodality cancer treatment protocol.

The multidisciplinary management team must clarify several aspects of breast cancer care that are commonly misunderstood by newly diagnosed patients. Often, patients are under the mistaken impression that mastectomy is a more “aggressive” approach to treating their cancer, simply because it represents more extensive surgery. Similarly, patients often assume that mastectomy provides a guarantee that they will never have to deal with breast cancer again, or that undergoing this surgery will help them to avoid needing chemotherapy. These misperceptions will not necessarily be verbalized, so it is incumbent upon the clinician to clearly communicate the following facts to the patient:

• Survival is equivalent for breast-conserving surgery and mastectomy.

• Mastectomy does not eliminate the risk of local recurrence or new primary cancer.

• Chemotherapy recommendations are independent of the decision to pursue mastectomy vs lumpectomy.

• RT may still be indicated following mastectomy.

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