Background: Chronic smokers show differences in pain sensitivity compared to healthy non-smokers. Yet, no study to date has examined whether smoker status has an effect on postoperative pain.
Objective: We aim to examine a possible correlation between preoperative smoking and postoperative opioid dose based on the hypothesis that smokers would use higher doses of opioids to manage increased postoperative pain.
Study design: A retrospective observational cohort study.
Setting: The National Cancer Center in Korea.
Methods: We examined medical record data for patients who had undergone curative resection for either lung or esophageal cancer (lobectomy or bilobectomy for lung cancer or an Ivor Lewis operation for esophageal cancer) between January 1, 2006 and December 31, 2010. We examined the correlation between the total preoperative average number of packs per day multiplied by years of cigarette smoking (pack-years) and morphine equivalent daily doses administered to patients after surgery, considering each type of cancer both individually and together. Partial correlation and regression analyses were performed to determine the causality of a possible relationship between pack-years of cigarette smoking and postoperative opioid dose.
Results: A total of 1,129 patients (871 patients with lung cancer and 258 patients with esophageal cancer) were included in the final analysis. There was no significant correlation between total pack-years of cigarette smoking and postoperative opioid dose for lung cancer, esophageal cancer, or both cancer types combined (r = 0.042, -0.012, and 0.037, respectively). In the analysis of both cancer types combined, video-assisted thoracic surgery (VATS) was associated with an 11.1% decrease in opioid dose (β = -0.111, P = 0.003) and epidural analgesia was associated with a 7.2% increase in opioid dose (β = 0.072, P = 0.042).
Limitations: The retrospective design of this study is a limitation.
Conclusion: Our study did not observe a correlation between preoperative smoking and postoperative opioid dose in patients with lung or esophageal cancer.
Key words: Smoking, postoperative pain, opioid, lung cancer, esophageal cancer, analgesia.