Modified Radical Mastectomy

Christine Dauphine, MD, FACS
Content Author:
Brian Burbidge , Kaya Garringer , Calder Dorn , Matthew Zeller
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Background Information: 

Mastectomy is defined as the surgical removal of all breast tissue within the breast. 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-areolar sparing mastectomy, and lumpectomy with or without sentinel lymph node biopsy 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 breast (including the skin and nipple), 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, skin sparing mastectomy aims to retain more of the natural skin of the breast to improve post-operative cosmesis. Nipple-areolar sparing mastectomy maintains the dermal and epidermal layers of nipple and areola only, removing all other parts of the breast including the 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.  Specific pathology treated with mastectomy:

  • 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 mastectomy to prevent progression to invasive breast cancer
  • Other invasive breast lesions, including those caused by Paget disease 
  • BRCA1/2 mutation (prophylactic)ⁱ

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
  • Musculature
  • ~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 (innervates serratus)
  • ~Thoracodorsal nerve (innervates latissimus)
  • ~Brachial plexus


General surgical risks:

  • Bleeding
  • Infection

Risks specific to procedure:

  • Seroma (varied results of seroma formation: incidence of 15.5%³, 8.4%⁴, 35%⁵) 
  • Skin flap necrosis - rates vary based on study
  • ~10.7% in skin-sparing procedures², 11.2% in non-skin sparing procedures⁶, combined skin-sparing and non-skin sparing, 14%⁷
  • Nipple necrosis, particularly in nipple-areolar sparing mastectomies (5.9%8-15%⁹)
  • Pain, paresthesias (50%ⁱ⁰)
  • Nerve injury and associated long term effect
  • ~Long thoracic nerve → Winged scapula deformity
  • ~Thoracodorsal trunk → Weakened shoulder adduction 
  • ~Medial pectoral nerve → Pectoralis major atrophy
  • ~Intercostal brachial cutaneous nerve → Reduced sensation to medial aspect of upper extremity & dysesthesias
  • Lymphedema (19.8% for mastectomy with axillary lymph node dissectionⁱⁱ)

Key Literature:

  • ACOSOG Z0011 Trialⁱ²
  • ~A randomized control trial assessing the effect of axillary dissection on survival of 856 women with invasive primary breast cancer, no palpable axillary lymphadenopathy, and maximum 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 10 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 who meet the criteria of those in the study. These results have greatly reduced the use of axillary dissection, which has been connected to significant morbidity in breast cancer management. 

Additional resources: 


  • Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice by Courtney M. Townsend Jr. JR. MD
  • Atlas of General Surgical Techniques: Townsend, Evers

Online resources:

  1. Domchek SM, Friebel TM, Singer CF, Evans DG, Lynch HT, Isaacs C, et al. Association of risk-reducing surgery in BRCA1 or BRCA2 mutation carriers with cancer risk and mortality. JAMA. 2010 Sep 1;304(9):967-75. doi: 10.1001/jama.2010.1237. PMID: 20810374; PMCID: PMC2948529.
  2. Carlson GW, Bostwick J 3rd, Styblo TM, Moore B, Bried JT, Murray DR, Wood WC. Skin-sparing mastectomy. Oncologic and reconstructive considerations. Ann Surg. 1997 May;225(5):570-5; discussion 575-8. doi: 10.1097/00000658-199705000-00013. PMID: 9193184; PMCID: PMC1190797.
  3. Woodworth PA, McBoyle MF, Helmer SD, Beamer RL. Seroma formation after breast cancer surgery: incidence and predicting factors. The American surgeon. 2000;66(5):444-450. 
  4. Boostrom SY, Throckmorton AD, Boughey JC, Holifield AC, Zakaria S, Hoskin TL, Degnim AC. Incidence of clinically significant seroma after breast and axillary surgery. J Am Coll Surg. 2009 Jan;208(1):148-50. doi: 10.1016/j.jamcollsurg.2008.08.029. Epub 2008 Oct 2. PMID: 19228516.
  5. Hashemi E, Kaviani A, Najafi M, Ebrahimi M, Hooshmand H, Montazeri A. Seroma formation after surgery for breast cancer. World J Surg Oncol. 2004 Dec 9;2:44. doi: 10.1186/1477-7819-2-44. PMID: 15588301; PMCID: PMC543447.
  6. Robertson SA, Jeevaratnam JA, Agrawal A, Cutress RI. Mastectomy skin flap necrosis: challenges and solutions. Breast Cancer (Dove Med Press). 2017 Mar 13;9:141-152. doi: 10.2147/BCTT.S81712. PMID: 28331365; PMCID: PMC5357072.
  7. Matsen CB, Mehrara B, Eaton A, Capko D, Berg A, Stempel M, Van Zee KJ, Pusic A, King TA, Cody HS 3rd, Pilewskie M, Cordeiro P, Sclafani L, Plitas G, Gemignani ML, Disa J, El-Tamer M, Morrow M. Skin Flap Necrosis After Mastectomy With Reconstruction: A Prospective Study. Ann Surg Oncol. 2016 Jan;23(1):257-64. doi: 10.1245/s10434-015-4709-7. Epub 2015 Jul 21. PMID: 26193963; PMCID: PMC4697877.
  8. Headon HL, Kasem A, Mokbel K. The Oncological Safety of Nipple-Sparing Mastectomy: A Systematic Review of the Literature with a Pooled Analysis of 12,358 Procedures. Arch Plast Surg. 2016 Jul;43(4):328-38. doi: 10.5999/aps.2016.43.4.328. Epub 2016 Jul 20. PMID: 27462565; PMCID: PMC4959975.
  9. Agha RA, Al Omran Y, Wellstead G, Sagoo H, Barai I, Rajmohan S, Borrelli MR, Vella-Baldacchino M, Orgill DP, Rusby JE. Systematic review of therapeutic nipple-sparing versus skin-sparing mastectomy. BJS Open. 2018 Dec 19;3(2):135-145. doi: 10.1002/bjs5.50119. PMID: 30957059; PMCID: PMC6433323.
  10. Tasmuth, T., von Smitten, K., Hietanen, P., Kataja, M., & Kalso, E. (1995). Pain and other symptoms after different treatment modalities of breast cancer. Annals of Oncology, 6(5), 453–459.
  11. Miller, C. L., Specht, M. C., Skolny, M. N., Horick, N., Jammallo, L. S., O’Toole, J., … Taghian, A. G. (2014). Risk of lymphedema after mastectomy: Potential benefit of applying ACOSOG Z0011 protocol to mastectomy patients. Breast Cancer Research and Treatment, 144(1), 71–77.
  12. Giuliano AE, Ballman KV, McCall L, et al. Effect of Axillary Dissection vs No Axillary Dissection on 10-Year Overall Survival Among Women With Invasive Breast Cancer and Sentinel Node Metastasis: The ACOSOG Z0011 (Alliance) Randomized Clinical Trial. JAMA. 2017;318(10):918–926. doi:10.1001/jama.2017.11470.