With the diagnosis of breast cancer indications, the type of therapy offered to a breast cancer patient is determined by the stage of the disease (Table 2). Survival rates for women diagnosed with breast cancer between 1983 and 1987 have been calculated based on Surveillance, Epidemiology, and End Results (SEER) Program data. Five-year survival for stage I patients is 94%, for stage IIa, 85%, and for stage IIb, 70%, while for stage IIIa patients 5-year survival is 52%, for stage IIIb, 48%, and for stage IV (distant disease), 18%.

The more recently utilized mastectomy is the skin-sparing mastectomy, which removes all breast tissue, the nipple–areola complex, and only 1 cm of skin around excised scars. There is a recurrence rate of less than 2% to 4% when skin-sparing mastectomy is used for T1 to T3 cancers. A total
(simple) mastectomy removes all breast tissue, the nipple–areola complex, and necessary skin. An extended simple mastectomy removes all breast tissue, the nipple–areola complex, necessary skin, and the level I axillary lymph nodes. The modified RM removes all breast tissue, the nipple–areola complex, necessary skin, and the level I and II axillary lymph nodes. The Patey modification of the modified RM also removes the pectoralis minor muscle, which permits complete dissection of the apical (level III) axillary lymph nodes. The Halsted RM removes all breast tissue, the nipple–areola complex, necessary skin, the pectoralis major and pectoralis minor muscles, and the level I, II, and III axillary lymph nodes. Currently, chemotherapy, hormone therapy, and radiation therapy for breast cancer have nearly eliminated the need for a Halsted RM.

Positioning: the patient is positioned on the operating table in the supine position for induction of general endotracheal anesthesia (Fig. 2). Rolled towels provide modest nonrestrictive elevation of the ipsilateral hemithorax and shoulder so that shoulder movement is not compromised. Positioning the patient at the edge of the operating table affords the surgeon and the surgical assistant ample access to the breast and axilla and avoids undue retraction on the pectoralis muscle groups or the brachial plexus. The ipsilateral breast, neck, shoulder, and hemithorax are prepped down to the operating table and across the midline of the chest. Folded towels are used to expose the prepped operative field, which includes the shoulder, lower neck, sternum, and upper abdominal musculature. The towels are secured in place with towel clips or surgical staples. In addition, the ipsilateral axilla, arm, and hand are fully prepared within the operative field and the arm is positioned on an arm board that is placed perpendicular to the operating field. While alternative methods exist for including the arm and hand in the operative field, isolation of the hand and forearm with an occlusive cotton dressing (stockinette) is preferred. The stockinette is secured in place by applying an elastic or cotton bandage distal to the ipsilateral elbow, thereby ensuring free mobility of the ipsilateral elbow, arm, and shoulder.

Prior to commencement of the procedure, the first surgical assistant is positioned cephalad to the shoulder of the ipsilateral breast, cephalad to the arm board (Fig. 2). This position permits the assistant to position the arm and shoulder and retract the pectoral muscles appropriately at the time of the axillary dissection. In an obese patient with large breasts, a second surgical assistant can be positioned on the contralateral side of the operating table to assist with exposure of the axilla during axillary dissection.

Incisions appropriate for cancers occupying various locations in the breast are shown in Figures 3 to 9. The elliptical incision of the breast skin incorporates the nipple–areolar complex and skin overlying the breast cancer en bloc with skin margins that lie 1 to 2 cm from the cephalad and caudad extents of the cancer.

With electrocautery or scalpel, flaps are developed that extend to the boundaries of dissection for the modified RM and include (a) the anterior margin of the latissimus dorsi muscle laterally; (b) the midline of the sternum medially; (c) the subclavius muscle superiorally; and (d) the caudal extension of the breast, which is 3 to 4 cm inferior to the inframammary fold, inferiorly (Fig. 10, inset). The skin edges are elevated at a right angle to the chest wall to adequately expose the superficial fascia (Fig. 10). Skin flaps include the skin and tela subcutanea and vary in thickness depending on body habitus (Fig. 11A). The appropriate dissection plane for skin flap elevation is deep to the subcutaneous vasculature and superficial to the vessels of the breast parenchyma. The surgeon elevates the skin flap with consistent thickness to avoid creation of devascularized subcutaneous tissues, which can contribute to wound seroma, skin necrosis, and flap retraction (Fig. 11B).

Following the development of skin flaps, the breast parenchyma and pectoralis major fascia is elevated from the underlying pectoralis major muscle in a plane parallel with the muscle bundles as they course from their medial origin (ribs 2 to 6) to their lateral insertion on the humerus (Fig. 11B). Perforating vessels from the lateral thoracic or anterior intercostal arteries, which are end arteries that supply the pectoralis major and minor muscles and breast parenchyma, are regularly encountered during elevation of the breast parenchyma and pectoralis major fascia. These vessels are individually identified and ligated with 2-0 or 3-0 nonabsorbable sutures. Elevation of the breast parenchyma and pectoralis major fascia is continued laterally until the lateral edge of the pectoralis major muscle and the underlying pectoralis minor muscle are exposed. The surgeon is aware of the anatomic location of the lateral neurovascular bundle in which the medial pectoral nerve (laterally placed with origin from the medial cord) courses to innervate the pectoralis
major and minor muscles. If possible, this nerve is preserved to prevent atrophy of the lateral head of the pectoralis major—a significant cosmetic and functional defect (Table 3).

Once elevation of the breast parenchyma and pectoralis major muscle fascia from the underlying pectoralis major muscle is completed, an incontinuity axillary lymph node dissection is performed (Figs. 12, 13). The investing fascia of the axillary space is sharply divided (Fig. 12), the pectoralis minor muscle is defined, and lymph nodes, which may lie between the pectoralis muscles (Rotter’s nodes), are cleared. As the axillary lymph node dissection proceeds, the loose areolar tissue of the lateral axillary space is elevated with identification of the lateral extent of the axillary vein in its course anterior and caudad to the brachial plexus and axillary artery (Fig. 12). (The axillary contents can also be removed in a medial to lateral direction.) The investing layer of the axillary vein is dissected sharply, with dissection allowing complete visualization of the anterior and ventral surfaces of the vein. Ligation and division of intervening venous tributaries is performed. Retraction of the superomedial aspect of the pectoralis major muscle exposes the lateral pectoral nerve, which originates from the lateral cord, and is protected to preserve innervation to the medial heads of the pectoralis major muscle (Figs. 12, 13, Table 3). Dissection continues medially on the anteroventral surface of the axillary vein and the loose areolar tissue at the juncture of the axillary vein with the anterior margin of the latissimus dorsi muscle is swept inferomedially to include the lateral group of axillary lymph nodes (level I, see Fig. 12). The intercostobrachial nerves are infrequently visualized, except for the superior trunk that commonly divides close to the chest wall and courses through the level II axillary lymph nodes that lie below the axillary vein. Generally, no attempt is made to salvage the superior trunk and branches of the intercostobrachial nerve (Table 3).

Preservation of the thoracodorsal artery and vein, located deep in the axillary space, is advocated and these structures are invested with loose areolar tissue and the axillary lymph nodes of the lateral and subscapular groups (Figs. 12, 13). The thoracodorsal nerve originates from the posterior cord medial to the thoracodorsal artery and vein and is visualized and protected along its variable inferolateral course en route to its innervation of the latissimus dorsi muscle. The lateral axillary lymph node group (Fig. 12) is retracted inferomedially and anterior to the thoracodorsal neurovascular bundle and dissected en bloc with the subscapular group of axillary lymph nodes (level I), which are medially located between the thoracodorsal nerve and the lateral chest wall. Dissection of the posterior contents of the axillary space exposes the posterior boundary of the axilla, allowing visualization of the heads of the teres major muscle laterally and the subscapularis muscle medially. Dissection then proceeds medially with extirpation of the central axillary lymph node groups (level II, see Fig. 12, inset). The superomedial aspect of the dissection
specimen can be identified with a metallic marker or suture to provide anatomic orientation for the pathologist. The surgeon continues the dissection en bloc to avoid separation of nodal groups and disruption of lymphatic vessels in the axilla. With medial dissection, the surgeon encounters the chest wall deep in the medial axillary space and is able to identify and preserve the long thoracic nerve (Bell’s respiratory nerve), which is constant in its location, anterior to the subscapularis muscle, and is closely applied to the investing fascial compartment of the chest wall. The long thoracic nerve is dissected from cephad to caudad longitudinal to course and it is completed at point of innervation of serratus anterior muscle (Figs. 12, 14). Damage to the nerve causes permanent disability with a “winged scapula” deformity secondary to denervation of the serratus
anterior muscle (Table 3). The axillary contents anterior and medial to the long thoracic nerve are then swept inferomedially with the dissection specimen. The surgeon ensures that the long thoracic and thoracodorsal nerves are completely visualized before dividing the inferior extent of the axillary dissection.

With the presence of level III lymphadenopathy, the Patey modification of the modified RM is employed to enhance locoregional control (Fig. 13). As the surgeon proceeds medially to complete dissection along the lateral margin of the pectoralis major muscle, abduction of the shoulder and extension of the arm along with finger dissection at the lateral margin of the pectoralis major muscle allows visualization
of the insertion of the pectoralis minor muscle on the coracoid process of the scapula. The Patey modification involves division of the tendinous portion of the pectoralis minor muscle (Fig. 12) near its insertion on the coracoid process with/without removal of the muscle, which permits access to the apical axillary lymph nodes (level III) and visualization of the full extent of the axillary vein as it courses beneath the pectoralis minor muscle to its confluence with the subclavian vein beneath the costoclavicular ligament (Halsted’s ligament).