Modified Radical Mastectomy: Surgical Steps
Modified radical mastectomy involves complete removal of breast tissue with preservation of the pectoralis major muscle, combined with level I and II axillary lymph node dissection. 1
Pre-Operative Requirements
Confirm absence of distant metastases before proceeding - a metastatic screen is mandatory as modified radical mastectomy should only be performed in non-metastatic disease. 1
Surgical Technique
Incision and Skin Flap Development
- Create an elliptical incision encompassing the nipple-areola complex and any previous biopsy sites, extending from the sternal border medially to the latissimus dorsi laterally. 2
- Develop superior and inferior skin flaps to expose the entire breast tissue from the clavicle superiorly to the inframammary fold inferiorly, and from the sternal border to the latissimus dorsi. 2
- Maintain flap thickness to preserve blood supply while ensuring complete removal of breast tissue. 1
Breast Tissue Removal
- Preserve the pectoralis major muscle entirely - this is the defining feature distinguishing modified radical from radical mastectomy. 2
- Remove all breast tissue from the pectoralis major fascia, working from medial to lateral. 2
- The pectoralis minor muscle may be either resected or preserved depending on the extent of axillary dissection required. 2
Axillary Lymph Node Dissection
Standard dissection includes level I and II nodes (lateral and posterior to pectoralis minor). 3
- Identify and preserve the long thoracic nerve (innervates serratus anterior) and thoracodorsal nerve and vessels (supply latissimus dorsi). 3
- Dissect lymph nodes from the axillary vein inferiorly, working lateral to medial. 3
- For level III dissection (when apical nodes are involved): Split the pectoralis major muscle 2 cm inferior to the clavicle to expose the subclavian region, then perform skeletonized dissection along the subclavian vein. 3
- Protect pectoralis branches of the thoracoacromial artery and lateral cutaneous branches of intercostal nerves to reduce postoperative complications including upper limb numbness and muscle atrophy. 3
Hemostasis and Closure
Achieve meticulous hemostasis - this is the single most important factor in preventing hematoma formation, which creates interpretation difficulties on physical exam and mammography. 4
- Do not routinely place drains in breast tissue as they do not effectively prevent hematomas and may worsen outcomes; allow the cavity to fill with serum for better cosmetic results. 4
- Close in layers, approximating the skin flaps without tension. 2
Post-Operative Management
If lymph node involvement is confirmed, chest wall and regional lymph node radiotherapy (internal mammary chain, infra- and supraclavicular) is mandatory. 1
Critical Contraindications
- Presence of distant metastases - systemic therapy must be completed first (minimum 4-6 months) before considering surgery in stage IV disease. 5
- Extensive tumor involvement of the skin or inflammatory breast cancer. 6
- Never perform immediate breast reconstruction in the presence of risk factors for locoregional recurrence or if it would jeopardize administration of adjuvant treatments. 1