Smoking and Complications After Cancer Surgery A Systematic Review and Meta-Analysis

IMPORTANCE Surgical cancer treatments may be delayed for patients who smoke over concerns for increased risk of complications. Quantifying risks for people who had recently smoked can inform any trade-offs of delaying surgery. OBJECTIVE To investigate the association between smoking status or smoking cessation time and complications after cancer surgery. DATA SOURCES Embase, CINAHL, Medline COMPLETE, and Cochrane Library were systematically searched for studies published from January 1, 2000, to August 10, 2023. STUDY SELECTION Observational and interventional studies comparing the incidence of complications in patients undergoing cancer surgery who do and do not smoke. DATA EXTRACTION AND SYNTHESIS Two reviewers screened results and extracted data according to the Meta-Analyses of Observational Studies in Epidemiology (MOOSE) reporting guidelines. Data were pooled with a random-effects model and adjusted analysis was performed. MAIN OUTCOMES AND MEASURES The odds ratio (OR) of postoperative complications (of any type) for people who smoke currently vs in the past (4-week preoperative cutoff), currently smoked vs never smoked, and smoked within shorter (2-week cutoff) and longer (1-year cutoff) time frames. RESULTS The meta-analyses across 24 studies with a pooled sample of 39 499 participants indicated that smoking within 4 weeks preoperatively was associated with higher odds of postoperative complications compared with ceasing smoking for at least 4 weeks (OR, 1.31 [95% CI, 1.10-1.55]; n = 14 547 [17 studies]) and having never smoked (OR, 2.83 [95% CI, 2.06-3.88]; n = 9726 [14 studies]). Within the shorter term, there was no statistically significant difference in postoperative complications between people who had smoked within 2 weeks preoperatively and those who had stopped between 2 weeks and 3 months in postoperative complications (OR, 1.19 [95% CI, 0.89-1.59]; n = 5341 [10 studies]), although the odds of complications among people who smoked within a year of surgery were higher compared with those who had quit smoking for at least 1 year (OR, 1.13 [95% CI, 1.00-1.29]; N = 31 238 [13 studies]). The results from adjusted analyses were consistent with the key findings. CONCLUSIONS AND RELEVANCE In this systematic review and meta-analysis of smoking cessation and complications after cancer surgery, people with cancer who had stopped smoking for at least 4 weeks before surgery had fewer postoperative complications than those smoking closer to surgery. High quality, intervention-based evidence is needed to identify the optimal cessation period and inform clinicians on the trade-offs of delaying cancer surgery.