Mastectomy

Overview:

  • Most commonly indicated for breast cancer excision
  • Often combined with chemotherapy and/or radiation therapy
  • Variations include:
  1. Breast lumpectomy – breast-conserving treatment with wide local excision for a benign, solid mass or Stage I and II breast cancer with adjuvant radiation therapy and lymph node biopsy
  2. Modified radical mastectomy – local management of Stage II breast cancer in certain situations, or Stage III breast cancer. Removes breast tissue and axillary lymph nodes but does not resect pectoral muscles, while radical mastectomy does
  3. Simple/total mastectomy – removes breast tissue only
  • May also be combined with axillary lymph node dissection or sentinel lymph node biopsy, which uses dye or radioisotope injection to identify drainage from the tumor

Summary of Procedure:

Position:

  • Supine with ipsilateral arm abducted 90 degrees

Incision:

  • Modified Radical or Radical Mastectomy: large sub-mammary incision, possible drain placement
  • Partial mastectomy: small incision on breast
  • Axillary dissection: vertical incision in axilla

Special instruments:

  • Sentinel lymph node dissection may require methylene blue which can cause brief interference with pulse oximetry when injected. Other dyes may cause anaphylaxis.

Antibiotics:

  • Cefazolin for mastectomy unless significant allergy to cephalosporins
  • Check with surgeon for antibiotics for lumpectomy

Surgical time:

  • Lumpectomy – 1 hour
  • Mastectomy – 2 hours

Estimated Blood Loss:

  • 50 – 200mL

Postoperative care:

  • PACU and ward

Complications:

  • Chronic incisional pain
  • Hematoma or seroma
  • Brachial plexus injury from positioning
  • Nerve damage to intercostobrachial nerve (axillary and upper arm sensory deficit), thoracodorsal nerve (weakened shoulder abduction), long thoracic nerve (‘winged’ scapula)

Pain score:

  • 3-6/10

Anesthesia Concerns:

  • Preoperative chemotherapy: doxorubicin chemotherapy may cause cardiomyopathy; other chemotherapy may cause anemia
  • Metastatic breast cancer: may go to CNS with neurologic deficits or bone with hypercalcemia
  • Neuromuscular blockade may prevent identification of long thoracic nerve during axillary dissection

Recommended management:

Preoperative evaluation and optimization

  • Assess for comorbidity from chemotherapy, metastasis, or other disease
  • Baseline Hgb advised for patients with cancer or prior chemotherapy: if Hgb > 10g/dL then GXM is not necessary
  • Encourage oral clears intake until 2 hours before surgery
  • Preoperative PO paracetamol 1g, if available
  • Patients with chronic pain may receive gabapentin 300g

Intraoperative anesthetic technique

Monitoring:

  • Standard monitors

Access:

  • 1 PIV – avoid any access or BP cuff on the same side as the mastectomy especially with lymph node dissection

Blood and fluid requirements:

  • Minimal to moderate blood loss
  • NS/LR @ 3-5mL/kg/hr

Induction:

  • Standard induction based on comorbidities; consider suxamethonium or low dose atracurium for intubation

Airway:

  • Lumpectomy – LMA may be used
  • Mastectomy – ETT, avoid long-acting NMBs with axillary dissection

Analgesia:

  • If PECS I and PECS II blocks are performed (mastectomy only, not lumpectomy), they may be done directly after intubation prior to surgical start. Anatomy may be distorted, or dressing may interfere with block performed at the end of the case. PECS does not interfere with identification of nerves
    • 20mL 0.5% bupivacaine between serratus and pec minor muscle (PECS II)
    • 10mL of 0.5% bupivacaine between pec major and minor muscles (PECS I)
    • For bilateral mastectomy use 0.25% bupivacaine
  • Erector spinae plane block (T5 level, 20mL 0.25% bupivacaine) or retrolaminar block (T3 and T5 level, 15mL each 0.25% bupivacaine) are acceptable alternatives
  • Analgesia with block (preferred), paracetamol, diclofenac, and low-dose morphine

Maintenance:

  • Propofol infusion or TIVA may reduce risk of PONV

Emergence:

  • PONV prophylaxis with dexamethasone and ondansetron
  • Full reversal of NMB, if given

Critical events

  • Avoid PIV on side of axillary dissection
  • Avoid long-acting NMB for axillary dissection

Complications

  • PONV risk is moderate to high

Postoperative management

  • Multimodal pain management including regional block, scheduled oral ibuprofen and oral paracetamol
  • Breast lumpectomy may go home same day

References:

  1. Sherwin. Anesthesia for Breast Surgery. BJA Education. 2018. link