Anaesthesia for breast surgery

Key points.

• •The prevalence of breast cancer is increasing.
• •Surgery can involve the primary removal of the lesion and reconstruction.
• •Preoperative assessment is paramount for allaying anxiety and identifying potential intraoperative issues.
• •Pectoral nerve blocks and serratus anterior block provide good analgesia for day-case procedures.
• •Ongoing research is investigating anaesthetic techniques and their effect on cancer recurrence.

Learning objectives.

By reading this article, you should be able to:

• •Explain the perioperative management of a patient for breast cancer surgery.
• •Summarise the types of breast cancer surgery and their uses.
• •Describe the common regional anaesthetic techniques that can be used for surgery.

Breast surgery is performed for a number of indications, including benign lump excision, drainage of abscess, or cosmetic procedures, but the most common indication is for breast cancer excision. The incidence of breast cancer has increased by almost 20% since the 1990s in the UK. It accounts for 12% of new cancer diagnoses and a quarter of all cancers in women. Breast cancer is also a leading cause of cancer death in women, second only to lung cancer. Breast cancer can be classified into different histological and molecular subtypes, which determines the prognosis and treatment (Table 1).

Table 1.

Histological and molecular subtypes of breast cancer. Luminal A cancers have a good prognosis and are frequently oestrogen (ER) and progesterone (PR) positive. Triple-negative breast cancer is ER, PR, and human epidermal growth factor receptor 2 (HER2) negative, and associated with a poorer prognosis than other molecular subtypes

Histological subtypes	Molecular subtypes
Preinvasive cancer (25%) Ductal carcinoma in situ (80%) Lobular carcinoma in situ (20%) Invasive cancer (75%) Invasive ductal carcinoma (80%) Invasive lobular carcinoma (10%) Other (10%)	Luminal A (40%) Luminal B (20%) HER2 positive (10–15%) Triple negative (15–20%)

Breast surgery types

Radical mastectomy, frequently performed 20 yr ago, is now rarely indicated in modern breast surgery. A number of landmark trials have proved the efficacy of breast-conserving treatment (BCT), such as wide local excision of the tumour in addition to radiotherapy or chemotherapy, in comparison to full mastectomy alone. This surgery requires a histological confirmation that a minimum margin (typically 5 mm) of normal tissue has been excised around the tumour. Contraindications to BCT include multifocal disease, inflammatory breast cancer, and prior radiation to the breast.¹

Approximately 30% of patients require full mastectomy because of personal choice or their unsuitability for BCT. Some patients wish to have prophylactic mastectomies for risk reduction surgery, which can be simple, skin-sparing, or nipple-sparing mastectomy. Radical mastectomy is reserved for tumours that invade the pectoral muscles.²

Sentinel lymph node biopsy

Axillary lymph node dissection (ALND) has now been largely replaced by the minimally invasive technique of sentinel lymph node biopsy (SLNB) for breast cancer staging. The sentinel lymph node is the first node or group of lymph nodes that drains from the primary cancer, and is therefore most likely to contain metastatic disease. Sentinel lymph node mapping is usually carried out with a combination of radioisotopes and dye injected near the tumour during surgery for removal of primary cancer. The lymph nodes (typically one to four) with the highest radioactive signals will then be removed.

SLNB has been found to be equally effective at predicting the status of axillary lymph nodes with far fewer adverse effects than ALND. These include lymphoedema (characterised by painful swelling of the ipsilateral upper limb), upper limb sensory loss, increased length of hospital stay, and prolonged time to recovery of normal activities.³ Women with positive SLNB may require subsequent ALND and further adjuvant treatment.

SLNB is not without perioperative risk. Isosulfan blue and Patent Blue V are two of the primary dyes used in SLNB; these have been associated with immunoglobulin E-mediated anaphylactic reactions. These anaphylactic reactions can range from urticarial rash only to hypotension requiring vasopressor support and even cardiac arrest.⁴ The overall risk of anaphylaxis has been estimated at 1%, and 0.17% for the more serious reactions. The recent publication of the National Audit Project 6 shows that Patent Blue V dye is the fourth most common cause of perioperative anaphylaxis.⁵ Methylene blue is potentially safer than the other blue dyes in terms of risk of anaphylaxis.⁶ However, interference with pulse oximetry and discolouration of skin and body fluids may occur, causing confusion in the postoperative setting.⁶

The anaesthetist should consider anaphylaxis to dye as a cause if there is an acute cardiovascular event during SLNB breast surgery. Development of the one-step nucleic acid amplification assay may allow the rapid detection of micrometastasis and could potentially provide an alternative to pathology for examining SLNB.⁷

Reconstruction

Breast reconstruction after tumour excision can take place immediately during the initial surgery or as a delayed procedure. Immediate reconstruction most commonly occurs in non-invasive cancers and risk reduction surgery. Reconstruction surgery can be performed using prosthetic or autologous material.

Prosthetic reconstruction can take place in either one- or two-stage procedures. Tissue expanders are placed under the pectoral muscles and gradually increased in size to create space for a future prosthesis. Prosthetic implants are generally silicone in nature.

Autologous reconstruction can take the form of either pedicled (rotational) flaps of tissue, which include skin, fat, and muscle with their accompanying vessels, or free flaps, which are harvested from the donor site and transferred to the breast for reconstruction.

The most commonly used pedicle flap is the transverse rectus abdominis myocutaneous (TRAM) flap. An ellipse of lower abdominal tissue is reflected along with perforating vessels into the defect of the breast. Latissimus dorsi (LD) flaps can also be used when TRAM flaps are not suitable, for example, in those at higher risk of flap failure secondary to diabetes or smoking. Pedicled flaps can involve long surgical times; increased operative blood loss, particularly if performed as immediate reconstruction; and severe acute postoperative pain.²

Regarding free-flap breast reconstruction, the deep inferior epigastric perforator (DIEP) flap spares the rectus abdominis muscle and solely uses skin and fat. The use of free flaps minimises the abdominal complications seen with the TRAM flap. Microsurgical anastomosis is required for this procedure, and there is a higher risk of flap failure caused by microvascular thrombosis.² These procedures are often prolonged (>8 h) and, like pedicled flaps, present a challenge in the management of severe postoperative pain. These procedures are usually performed in specialist centres.

Conduct of anaesthesia

Preoperative assessment

Patients for breast cancer surgery often have a high level of anxiety and contact with the anaesthetist before surgery may help allay some of their fears. It will also allow for the assessment and optimisation of their comorbidities, assessment of suitability for day-case surgery, and planning of regional anaesthesia and postoperative analgesia.

The patient's premorbid status, including adverse effects from any neoadjuvant hormonal, chemo-, or radiotherapy, should be considered. Neoadjuvant therapy can be used to reduce the size of locally advanced tumours and make initially inoperable cancers more amenable to resection. It is also used in those with inflammatory breast cancers and those who may wish to delay surgery if pregnant. Adjuvant chemotherapy is best timed within 90 days of surgery to improve outcomes.⁸ Many anaesthetic implications resulting from chemotherapy exist.⁹ Some chemotherapeutic agents (e.g. cyclophosphamide and doxorubicin) used in breast cancer can result in cardiac toxicity, including cardiomyopathy and prolongation of the QT interval. These events can occur at any stage after treatment, even years after the initial chemotherapy regimen.¹⁰ The patient should be assessed for symptoms of cardiac dysfunction before surgery, and investigations, such as ECG or echocardiography, may be required.

Haematopoietic adverse effects of neoadjuvant therapy, such as myelosuppression, can also occur; these manifest as perioperative anaemia, increased bleeding risk from thrombocytopaenia, and neutropaenia predisposing to sepsis.⁹ Identification and management of issues should occur before surgery. Myelosuppression usually reverses within 6 weeks of completion of chemotherapy. In the case of expected blood loss, the patient should have a sample sent for crossmatching of blood for transfusion.

Hormonal agents (e.g. tamoxifen or aromatase inhibitors) used in neoadjuvant treatment may be continued in the perioperative period. These include agents, such as the monoclonal antibody, trastuzumab (Herceptin), for human epidermal growth factor receptor 2-positive tumours. These agents can also be cardiotoxic and may increase the risk of perioperative venous thromboembolism (VTE).

In general, patients should continue to take regular prescribed medication, including aspirin, even on the morning of surgery. Exceptions include anticoagulant or antiplatelet therapy, which may need to be stopped for a minimum period to reduce the risk of perioperative bleeding. However, this risk should be weighed against the conflicting risk of thrombotic events that could result from temporarily withholding these therapies. Consultation with other relevant specialties may be required, with anticoagulant or antiplatelet ‘bridging’ therapy being an option where appropriate. In hypertensive patients, withholding angiotensin receptor blockers and angiotensin-converting inhibitors on the day of surgery reduces the risk of severe hypotension resulting from interactions with general anaesthetic agents.

Intraoperative management

Despite a formal preoperative assessment before the day of surgery, a majority of patients are acutely anxious. This should be addressed by discussion of anaesthesia and postoperative management, and prescription of premedication for anxiolysis if required.

Induction of anaesthesia should proceed by using monitoring standards as defined by The Association of Anaesthetists. Options include using i.v. or inhalation methods, and maintained using TIVA or a combination of inhalation and i.v. agents.

It is important to site i.v. cannulae in the contralateral arm to the surgery, particularly where axillary clearance is planned in order to avoid upper limb lymphoedema and optimise surgical access to the breast and axilla. Large-bore secure i.v. access is vital for administration of volume replacement or blood during prolonged procedures. After surgery, guidelines suggest avoiding the use of the ipsilateral arm for cannulation; however, evidence is lacking in support for this.11, 12

Haemodynamic monitoring includes invasive arterial pressure monitoring, depending on the procedure and the patient's co-morbidities. It is particularly important to consider if the patient has had cardiac complications from neoadjuvant therapy.

Shorter procedures may suit the use of supraglottic airway devices for airway management. Longer procedures, particularly where positioning other than supine is considered (e.g. for LD flap reconstruction), would be more suitable for airway management using tracheal intubation.

For those having procedures >30 min, temperature monitoring should be used and normothermia maintained.¹³ This is achieved most efficiently by using a convective forced air warmer, warmed fluids and increasing the ambient temperature.

For those having flap surgery, particularly free flaps, attention should particularly be paid to avoidance of hypothermia, hypovolaemia, and vasoconstriction in order to aid in perfusion of the flap during surgery.¹⁴ Adequate ventilation of the lungs with a normal PCO₂ and PO₂ will improve perfusion; it is imperative to avoid the excessive administration of i.v. fluids in order to reduce the incidence of postoperative tissue oedema.¹⁴

Positioning of the patient is also of prime importance. Often, breast procedures are carried out supine with the arm on the appropriate side abducted. Bilateral procedures can be performed with both arms abducted, in a ‘crucifix’ position. It is imperative to monitor the position of the arms to prevent any brachial plexus injuries caused by overstretching and misalignment of the neck and shoulder joints.

Patients for LD reconstruction may be placed laterally for a period and their position then changed during the procedure. This requires continuous vigilance from the anaesthetist, particularly regarding airway devices and i.v. access. Long procedures will also necessitate consideration of the types of pressure-relieving devices to be used for positioning, such as pressure-relieving jelly cushions and mattresses. It is also prudent to apply compression stockings for shorter procedures and sequential calf compression devices for longer procedures to reduce the risk of thromboembolism. Early postoperative VTE prophylaxis should also be considered because of the increased risk of thromboembolism in these patients.

The breast surgeon may request that the patient is positioned in a sitting position to assess for symmetry towards the end of the procedure. This can cause haemodynamic instability caused by pooling of blood and reduced venous return, which may require the use of vasopressors and fluid boluses.

Postoperative management

Patients who have had free-flap procedures will require general and flap monitoring in a high dependency unit for at least 24 h, with flap monitoring continuing over a number of postoperative days. Similar adherence to principles for intraoperative management of the flap should be continued in the postoperative period.¹⁴ Patients may also require a heated room to improve flap perfusion, depending on local practice.

Regular simple analgesics, such as paracetamol and NSAIDs, can complement the use of regional anaesthesia. Anti-emetics should be prescribed, and patients should be encouraged to mobilise early. A majority of patients undergoing minor procedures up to and including wide local excision with SLNB should be suitable for day-case surgery and may be discharged when established criteria are met.

Regional anaesthesia

Regional anaesthetic techniques, usually combined with general anaesthesia (GA), have become common in perioperative management of the patient for breast cancer surgery. The use of thoracic paravertebral, pectoral nerve blocks (PECS) I and II, and serratus anterior (SA) plane blocks are preferred techniques for breast surgery. Regional anaesthesia techniques provide an excellent postoperative analgesia, an opioid sparing, and reduction in postoperative nausea and vomiting (PONV).

Thoracic paravertebral block

The technique of thoracic paravertebral block (TPVB) has been well described.¹⁵ The technique allows for local anaesthetic (LA) to be injected into the paravertebral space, which is continuous with both the epidural and intercostal spaces. The clinician may perform a single shot, multiple-level injections, or placement of an indwelling catheter in the paravertebral space as part of the technique depending on the area to be targeted. For a mastectomy and axillary node dissection, one could consider performing the block at sites between T1 and T5. A single injection of 15 ml LA will usually produce a somatic block spread over three dermatomes, whilst multiple injections of 3–5 ml may be needed for larger spread of injectate.¹⁶

A recent review showed that, whilst there was little effect on intra- and postoperative opioid consumption and PONV, patients receiving either both single-shot injections or placement of paravertebral catheters had less acute pain in the first 72 h after surgery.¹⁷ There is also a suggestion that the use of TPVB for acute postsurgical pain may protect against the development of chronic postsurgical pain after breast surgery at 6 months.¹⁷

Complications are infrequent with TPVBs, but there is the potential for intra- and postoperative hypotension secondary to epidural spread of LA. This usually responds to small amounts of vasopressor therapy, administered in small boluses as required. Horner's syndrome and inadvertent intravascular injection may also occur in approximately 2% and 0.5%, respectively. However, the most common complication is failure of technique (10–15%) regardless of the use of ultrasound or a landmark technique.¹⁷

Thoracic epidural anaesthesia

Thoracic epidural anaesthesia (TEA) can also be used for analgesia during and after breast surgery. However, because of its technical difficulty and high failure rate (20%), TEA has been largely superseded by the other techniques, but still retains a role for prolonged reconstruction procedures (e.g. TRAM, LD, or DIEP reconstruction) or in major bilateral surgery. Thoracic epidural also carries a higher risk of hypotension and is unsuitable for day-case procedures. In almost all cases, postoperative care of the breast surgery patient who has TEA should be provided in a high dependency unit.

Pectoral nerve blocks

PECS I and PECS II are interfascial plane blocks first described as recently as 2012.¹⁸ PECS I blocks the medial and lateral pectoral nerves, whilst the PECS II block targets the lateral branch of the intercostal nerve; other nerves blocked include the intercostobrachial and long thoracic nerves. PECS II allows blockade of the axilla and intercostal nerves, which permits a wider area of surgical incision to be covered.

PECS I and II blocks require ultrasound guidance. The ultrasound probe is placed below the lateral third of the clavicle in an oblique plane, and the needle is advanced to the tissue plane between the pectoralis major and minor muscles at the level of the third rib. The probe is adjusted to visualise the fourth rib, and the needle is redirected to the deeper plane between the pectoralis minor and SA muscle.¹⁸ LA (e.g. levobupivacaine) can be deposited; volumes of 0.2 ml kg⁻¹ deposited at PECS I and 0.4 ml kg⁻¹ at PECS II are suggested. Fig 1, Fig 2 detail the ultrasound images associated with PECS I and II, respectively. PECS I and II blocks have the benefit of being fast acting, and unlike the TPVB or TEA, do not produce sympathetic block.

Fig 1.

Pectoral nerve block I. Local anaesthetic is deposited in the plane between the pectoralis major and minor muscles at the level of the third rib in the area indicated. LA, local anaesthetic; PM, pectoralis major; Pm, pectoralis minor.

Fig 2.

Pectoral nerve block II. Local anaesthetic is deposited in the plane between pectoralis minor and serratus anterior muscles in the area indicated. LA, local anaesthetic; NS, needle shaft; Pm, pectoralis minor; R4, rib 4.

Unsurprisingly, small clinical trials have shown that women for breast surgery receiving PECS blocks in combination with GA have reduced postoperative pain and opioid requirements compared to those who received GA alone.¹⁸

More convincingly, an RCT comparing single-shot TPVB with PECS blocks in women undergoing mastectomy under GA showed that PECS blocks delivered prolonged analgesia and less opioid consumption than TPVB.¹⁹ The authors suggested that the addition of the PECS II component gives good axillary analgesia because it produces blockade of the long thoracic nerves, unlike the TPVB.¹⁹

SA plane blocks

This technique was described for breast anaesthesia in 2013. The authors theorised that blockade of the lateral cutaneous branches of the thoracic intercostal nerves from T2 to T12 would provide analgesia to the anterolateral chest wall.²⁰ LA is deposited, under ultrasound guidance with an in-plane technique, deep to the LD muscle and superficial to the SA muscle in the mid-axillary area at the level of the fourth or fifth rib (Fig. 3). Again, a dose of 0.2 ml kg⁻¹ of long-acting LA is suggested.

Fig 3.

Serratus anterior plane block. Local anaesthetic should be deposited deep to latissimus dorsi and superficial to serratus anterior muscles in the mid-axillary area at the level of the fourth or fifth rib. LD, latissimus dorsi; NP, needle point; R5, rib 5; SA, serratus anterior.

Both PECS and SA plane blocks provide an alternative to TPVB and thoracic epidurals. They may be more suitable for day-case procedures, as there is no risk of neuraxial block. They may be performed safely after induction of GA, in contrast to TPVB or thoracic epidural, which are usually done awake to minimise nerve injury. There is also no risk of Horner's syndrome as with the other regional methods. They are safe and performed easily under ultrasound guidance.

Transversus thoracic plane block

The transversus thoracic plane block involves placement of LA bolus between the transverse thoracic muscle and the internal intercostal muscle at the level of the fourth and fifth ribs, anteriorly, at the costosternal junction (Fig. 4). This block aims to anaesthetise the anterior branches of the intercostal nerves T2–6 providing analgesia for the internal mammary region, and is optimally used to supplement PECS I and II blocks with additional medial analgesia for breast surgery.²¹ Injection of 15 ml levobupivacaine 0.15% was suggested by the authors.²¹

Fig 4.

Transversus thoracic plane block. Local anaesthetic should be deposited in the plane between the transversus thoracis muscle and the internal intercostal muscle at the level of the fourth or fifth rib. IC, internal intercostal muscle; Pl, pleural; R4, rib 4; R5, rib 5; TT, transversus thoracis muscle.

LA infusion analgesia

This involves placement of a catheter in the surgical wound, through which a LA solution is infused by active pumping mechanisms, typically at a rate of 4–10 ml h⁻¹.

Unsurprisingly, this provides better analgesia than placebo, but there are little data comparing its efficacy to regional block techniques. One such study recently showed that a combination of LA infusion analgesia with PECS I and PECS II blocks results in better analgesia over the first 24 h after surgery compared with either technique alone.²²

Anaesthesia and breast cancer recurrence

Mortality from breast cancer is rarely from the primary tumour itself, but rather from recurrence, which develops in about 30% of cases. Whilst most women with breast cancer receive surgical excision of the tumour, microscopic minimal residual cancer deposits remain despite an optimum surgical technique. This minimal residual cancer may either wither or flourish into subsequent metastasis, depending on a number of conflicting factors active in the perioperative period, including anaesthetic technique.

Although some retrospective analyses and a considerable body of laboratory studies suggest that anaesthetic technique might influence cancer recurrence, only a prospective, randomised trial can prove a causal relationship. Delivering these trials is expensive and challenging, because their primary endpoint is cancer-disease-free survival, and therefore, requires many years of meticulous follow-up of patients' progress.²³

One such multicentre international trial (clinical trial reference number: NCT00418457) has been ongoing for almost a decade and has randomised >2000 women with primary breast cancer to receive either inhalation anaesthesia with opioid analgesia or propofol TIVA with paravertebral regional anaesthesia. It will report shortly. Opioids have already demonstrated an ability to inhibit the function of natural killer cells and stimulation cancer cell proliferation by promoting angiogenesis and tumour cell signalling pathways.²⁴

The wider issue of whether the anaesthetic technique during cancer resection surgery affects the oncological outcomes has generated great interest worldwide. A collaboration amongst interested clinicians, scientists, and industry is supported by the EU and is open for membership (EU COST Action 15204 ‘Euro-Periscope’).²⁵

Conclusion

Breast cancer is the commonest cancer amongst women and one of the leading causes of cancer death. Most surgery in appropriately selected patients is suitable for day-case management. Prolonged surgery may be required for mastectomy with or without primary reconstruction. These techniques can be associated with large blood loss.

An appropriate preoperative assessment is the key. The anaesthetist should be aware of the potential benefits of regional anaesthesia techniques in reducing postoperative pain and opioid use. An ongoing research will clarify the effect of anaesthetic and analgesic technique on oncological outcomes.

Declaration of interest

The authors declare that they have no conflicts of interest.

MCQs

The associated MCQs (to support CME/CPD activity) will be accessible at www.bjaed.org/cme/home by subscribers to BJA Education.

Biographies

Aislinn Sherwin BSc (Physiotherapy) FCAI MCAI is the fellow in oncoanaesthesia and specialty registrar in anaesthesia at the Mater University Hospital, Dublin.

Donal Buggy MD MSc DME FRCPI FFSEM FCAI FRCA is consultant in anaesthesia at Mater University Hospital, and Professor of Anaesthesia & Perioperative Medicine at University College Dublin. He is a clinician scientist researching the influence of perioperative interventions on postoperative patient outcomes, and chairman of EU COST Action 15204 ‘Euro-Periscope’, a collaborative network of researchers in Europe investigating the potential influence of anaesthesia and analgesia on cancer outcomes. Professor Buggy is an elected member of the Council of the College of Anaesthetists of Ireland, and Chairman of the CEPD-Education committee. He is an editorial board member of BJA and is also a member of the research committee of the European Society of Anaesthesiologists.

Matrix codes: 1D02, 2A03, 3A03