Differential effects of serum from patients administered distinct anaesthetic techniques on apoptosis in breast cancer cells in vitro: a pilot study

In vitro and retrospective clinical studies suggest an association between anaesthetic technique during primary breast cancer surgery and cancer outcome. Apoptosis is an important step in the mechanism of breast cancer metastasis, but whether it is influenced by anaesthetic technique is unknown. Using serum from breast cancer surgery patients randomized to receive distinct anaesthetic techniques, we investigated its effect on apoptosis in oestrogen receptor (ER)-negative breast cancer cells in vitro. Women with biopsy-proven breast cancer were randomized to receive either propofol general anaesthesia with paravertebral analgesia (PPA) or standard sevoflurane general anaesthesia with opioid analgesia (SGA) in an ongoing, prospective clinical trial (NCT 00418457). Serum from a randomly selected subset of these patients (10 PPA and 10 SGA) who had donated 20 ml venous blood immediately before anaesthetic induction and at 1 h after operation was exposed to ER-negative MDA-MB-231 cells. Apoptosis was measured using ApoLive-Glo Multiplex Assay (TM). Exposure of MDA-MB-231 cells to postoperative serum of PPA patients resulted in higher luminescence ratio (apoptosis) than SGA patients, median (25-75%), 0.40 (0.35-0.43) compared with 0.22 (0.21-0.30), respectively (P=0.001). The luminescence ratio of postoperative serum from SGA was reduced compared with preoperative SGA 0.22 (0.21-0.30) compared with 0.3 (0.25-0.35) (P=0.045). Serum from patients given sevoflurane anaesthesia and opioids for primary breast cancer surgery reduces apoptosis in ER-negative breast cancer cells to a greater extent than serum from patients given propofol-paravertebral anaesthesia. Anaesthetic technique might affect the serum milieu in a manner that impacts cancer cell apoptosis, and thereby tumour metastasis.