Surgery is an important treatment modality for the majority of solid organ cancers. Unfortunately, cancer recurrence following surgery of curative intent is common, and typically results in refractory disease and patient death. Surgery and other perioperative interventions induce a biological state conducive to the survival and growth of residual cancer cells released from the primary tumour intraoperatively, which may influence the risk of a subsequent metastatic disease. Evidence is accumulating that anaesthetic and analgesic interventions could affect many of these pathophysiological processes, influencing risk of cancer recurrence in either a beneficial or detrimental way. Much of this evidence is from experimental in vitro and in vivo models, with clinical evidence largely limited to retrospective observational studies or post hoc analysis of RCTs originally designed to evaluate non-cancer outcomes. This narrative review summarises the current state of evidence regarding the potential effect of perioperative anaesthetic and analgesic interventions on cancer biology and clinical outcomes. Proving a causal link will require data from prospective RCTs with oncological outcomes as primary endpoints, a number of which will report in the coming years. Until then, there is insufficient evidence to recommend any particular anaesthetic or analgesic technique for patients undergoing tumour resection surgery on the basis that it might alter the risk of recurrence or metastasis.

Breast cancer recurs in 20% of patients following intended curative resection. In vitro data indicates that amide local anaesthetics, including lidocaine, inhibit cancer cell metastasis by inhibiting the tyrosine kinase enzyme Src. In a murine breast cancer surgery model, systemic lidocaine reduces postoperative pulmonary metastases. We investigated whether the additional administration of bosutinib (a known Src inhibitor) influences lidocaine’s observed beneficial effect in this in vivo model. Female BALB/c mice (n = 95) were inoculated with 25,000 4T1 cells into the mammary fad pad and after 7 days the resulting tumours were excised under sevoflurane anaesthesia. Experimental animals were randomized to one of four treatments administered intravenously prior to excision: lidocaine, bosutinib, both lidocaine and bosutinib in combination, or saline. Animals were euthanized 14 days post-surgery and lung and liver metastatic colonies were evaluated. Post-mortem serum was analysed for MMP-2 and MMP-9, pro-metastatic enzymes whose expression is influenced by the Src pathway. Lidocaine reduced lung, but not liver metastatic colonies versus sevoflurane alone (p = 0.041), but bosutinib alone had no metastasis-inhibiting effect. When combined with lidocaine, bosutinib reversed the anti-metastatic effect observed with lidocaine on sevoflurane anaesthesia. Only lidocaine alone reduced MMP-2 versus sevoflurane (p = 0.044). Both bosutinib (p = 0.001) and bosutinib/lidocaine combined (p = 0.001) reduced MMP-9 versus sevoflurane, whereas lidocaine alone did not. In a murine surgical breast cancer model, the anti-metastatic effects of lidocaine under sevoflurane anaesthesia are abolished by the Src inhibitor bosutinib, and lidocaine reduces serum MMP-2. These results suggest that lidocaine may act, at least partly, via an inhibitory effect on MMP-2 expression to reduce pulmonary metastasis, but whether this is due to an effect on Src or via another pathway remains unclear.

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). 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

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