Surgical Procedures

Modified Radical Mastectomy

What is Modified Radical Mastectomy?
August 23, 2021
Christine Dauphine, MD, FACS

Student Authors: Brian Burbidge, Kaya Garringer, Calder Dorn, Matthew Zeller

Background Information:

Mastectomy is generally defined as the surgical removal of all breast tissue. There are several types of mastectomy that are differentiated by the level of invasiveness and the anatomical structures that are preserved post-operatively. 

Modified radical mastectomy, simple mastectomy, skin-sparing mastectomy, nipple-areola sparing mastectomy, and lumpectomy with axillary lymph node dissection are most often utilized in practice. 

Radical mastectomy is no longer used regularly in modern surgery, as it is more invasive and has not shown to improve long-term outcomes over other options. Reconstruction of the breast can be done either immediately post-mastectomy or delayed, depending on the type of mastectomy performed.

Modified radical mastectomy (MRM) involves removal of the breast, pectoralis major fascia, and axillary lymph nodes (levels I and II). MRM may or may not be followed by breast reconstruction at a delayed date. 

Simple mastectomy is similar to MRM but does not involve the removal of axillary lymph nodes. Compared to both MRM and simple mastectomy, a skin-sparing mastectomy aims to retain more of the natural skin of the breast to improve post-operative cosmetic outcomes. Nipple-areola sparing mastectomy maintains the dermal and epidermal layers of nipple and areola only, removing all other parts of the breast including ducts.  


Mastectomy is indicated for both invasive and non-invasive breast cancers, particularly when a breast-conserving surgery (lumpectomy) is not sufficient for treatment. The type of mastectomy is determined based on the individual diagnosis, the stage of cancer, and patient preference.  

  • Invasive breast cancer: Mastectomy is often indicated in non-metastatic breast cancer (early-stage or locally advanced stages), particularly if patients are not candidates for breast-conserving surgery
  • Ductal carcinoma in situ (DCIS): Pre-cancerous neoplastic lesions that are localized to the breast ducts and lobules may be treated with a mastectomy to prevent progression to invasive breast cancer
  • Other invasive breast lesions, including those caused by Paget disease 
  • Reduction of breast cancer risk with BRCA1/2 mutation (prophylactic)1

Procedure Description:

Modified radical mastectomy involves completely removing the breast tissue and associated fascia as well as the axillary lymph nodes.

Long-acting paralytic agents should be avoided to monitor intact motor nerve function during the procedure—skin sparing mastectomy yields the best cosmetic outcome2.

Key Anatomy:

  • Breast tissue
  • Glandular and fibrous tissue
  • Fatty connective tissue
  • Areola
  • Nipple
  • Cooper’s ligaments 

  • Axillary lymph nodes
  • Levels I, II, III
  • Level I nodes are lateral/inferior to the pectoralis minor 
  • Level II nodes are deep to the pectoralis minor
  • Level III nodes are medial/superior to the pectoralis minor
  • Muscles
  • Pectoralis major 
  • Pectoralis minor 
  • Serratus anterior 
  • Latissimus dorsi 
  • Subscapularis 
  • Pectoral fascia
  • Vasculature

  • Axillary vein
  • Subscapular vein
  • Cephalic vein
  • Brachial vein
  • Basilic vein
  • Thoracodorsal vein
  • Nerves
  • Long thoracic nerve
  • Thoracodorsal nerve
  • Brachial plexus


  • General surgical risks (Bleeding, Infection)
  • Risks specific to the procedure:
  • Seroma (varied results of seroma formation: incidence of 15.5%2, 8.4%3, 35%4) 
  • Skin flap necrosis - rates vary based on a study
  • 10.7% in skin-sparing procedures5, 11.2% in non-skin sparing procedures6, combined skin-sparing, and non-skin sparing, 14%7
  • Nipple necrosis, particularly in nipple-areola sparing mastectomies (5.9%8-15%9)
  • Pain, paresthesias (50%10)
  • Nerve injury
  • Long thoracic nerve → Winged scapula deformity
  • Thoracodorsal trunk → Weakened shoulder adduction 
  • Medial pectoral nerve → Pectoralis major atrophy
  • Intercostal brachial cutaneous nerve → Reduced sensation to the medial aspect of upper extremity & dysesthesias
  • Lymphedema (19.8% for a mastectomy with axillary lymph node dissection11)

Key Literature:

ACOSOG Z0011 Trial 12

  • A randomized control trial assessing the effect of axillary dissection on the survival of 856 women with invasive primary breast cancer, no palpable axillary lymphadenopathy, and a maximum of 1-2 sentinel lymph nodes with metastases. In addition to lumpectomy, irradiation, and systemic therapy, two groups were treated with either sentinel lymph node dissection or axillary lymph node dissection and followed for almost ten years to collect data on survival and recurrence of cancer.

No significant difference was found between the groups, indicating that routine use of axillary dissection does not improve overall survival in breast cancer patients. These results have greatly reduced the use of axillary dissection, which has been connected to significant morbidity in breast cancer management.

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