Neoadjuvant Chemotherapy Does Not Decrease the Dose Requirement of Propofol for Inducing the Loss of Consciousness in Patients with Breast Cancer: A Prospective Study

Abstract

Background: Neoadjuvant chemotherapy can cause certain damage to patients’ physiological function. Therefore, we suspected that the sensitivity to propofol would also be altered by neoadjuvant chemotherapy. We aimed to compare the ED50 for inducing loss of consciousness (LOC) in patients with and without preoperative neoadjuvant chemotherapy. Methods: Sixty-two patients were randomized to receive neoadjuvant chemotherapy (group N) or not (group C) 10 to 15 days before elective modify radical mastectomy. The up-down method was used to determine the ED50 of propofol. Patients in each group received an initial dose of 4.0 μg/mL of propofol and a variable dose (increments or decrements) of 0.4 μg/mL of propofol based on the effective or ineffective response of the prior patient. The effective dose of propofol for induction of LOC in 50% patients was calculated and compared. Results: The EC50 and 95% confidence intervals (95%CI) of propofol in the two groups were 3.27 μg/mL (95%CI, 3.09～3.43 μg/mL) and 3.33μg/mL (95%CI, 3.19～3.47 μg/mL) for patients undergoing elective modified radical mastectomy with and without neoadjuvant chemotherapy respectively. Thus, there was no difference in the EC50s between the two groups, P = 0.55. Conclusions: Under the condition of this study, we found the EC50s of propofol for induction of LOC were 3.27 and 3.33 μg/mL for patients undergoing elective modified radical mastectomy in the presence or absence of neoadjuvant chemotherapy. We do not recommend reducing the dose of propofol for induction of LOC in patients with neoadjuvant chemotherapy.