Abstract
BACKGROUND: Breast cancer (BC) is the most frequent cause of cancer death in women. The thoracic pectoral nerve (PECS) block has been described as the gold standard analgesic modality for BC surgery. It has been previously reported that PECS is associated with decreased BC recurrence post-mastectomy. Although several anesthetic drugs and techniques are used in surgical oncology, their effects on the behavior of cancer cells are yet to be known and the key question of whether the anesthetic technique affects cancer outcome remains unresolved. OBJECTIVES: Since anesthetic drugs and techniques and post-operative pain may affect BC recurrence, this study aimed to determine whether the anesthetic choice and technique, PECS II block, affects in vitro apoptosis of the MDA-MB-231 BC cell line. METHODS: Twenty-two female BC patients, 20 to 75-years-old, with the same pathologic grades were included in this study. The patients were randomly divided into two groups. The first group received propofol general anesthesia (PGA) associated with PECS and the second group received standard PGA. Blood was sampled pre and post-operation from all patients. The sera were isolated and then exposed to the MDA-MB-231 human BC cell line. The mean percentage of apoptosis indices was analyzed by flow cytometry using Annexin V-fluorescein isothiocyanate 24 hours after treatment with patients' sera. RESULTS: A significant decrease was seen in the mean viability percentage of BC cell line in the PECS group, besides a significant increase in the mean percentage of necrosis and late apoptosis indices compared to the control group after exposure to sera collected from patients post-operation. Intra-group analysis of the control group showed that the exposure of the tumoral cell to post-operation sera resulted in a significant increase in the mean percentage of necrosis and late apoptosis index compared to pre-operation sera exposure. In the PECS group, the exposure of the tumoral cell to post-operation sera resulted in a significant increase in the mean percentage of cell viability and late apoptosis index compared to pre-operation sera exposure. CONCLUSIONS: In conclusion, anesthesia and BC surgery may induce apoptosis indices in the MDA-MB-231 human BC cell line. We also found that sera collected from PECS II block patients with BC could induce more apoptosis in the MDA-MB-231 cell line compared to collected sera from systemic analgesia alone after BC surgery.