Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR, China.
J Natl Cancer Inst. 2017 Dec 1;109(12). doi: 10.1093/jnci/djx115.
Tobacco smoking strongly increases risk of esophageal squamous cell carcinoma and moderately increases risk of esophageal adenocarcinoma. How smoking cessation influences esophageal cancer risk across histological subtypes, time latencies, and geographic regions is not clear.
Studies were systematically searched on Medline, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov. Pooled estimates of risk ratios (RRs) were derived using a random effects model. Cochran's Q test and I2 statistic were used to detect heterogeneity.
Among 15 009 studies, 52 fulfilled the inclusion criteria. Using nonsmokers as a reference, risk of esophageal squamous cell carcinoma was lower among former smokers (RR = 2.05, 95% confidence interval [CI] = 1.71 to 2.45) than among current smokers (RR = 4.18, 95% CI = 3.42 to 5.12). Compared with current smokers, a strong risk reduction was evident after five or more years (RR = 0.59, 95% CI = 0.47 to 0.75), and became stronger after 10 or more years (RR = 0.42, 95% CI = 0.34 to 0.51) and 20 or more years (RR = 0.34, 95% CI = 0.25 to 0.47) following smoking cessation. The risk reduction was strong in Western populations, while weak in Asian populations. Using nonsmokers as reference, the risk of esophageal adenocarcinoma was only slightly lower among former smokers (RR = 1.66, 95% CI = 1.48 to 1.85) than among current smokers (RR = 2.34, 95% CI = 2.04 to 2.69). The risk of esophageal adenocarcinoma did not show any clear reduction over time after smoking cessation, with a risk ratio of 0.72 (95% CI = 0.52 to 1.01) 20 or more years after smoking cessation, compared with current smokers.
Smoking cessation time-dependently decreases risk of esophageal squamous cell carcinoma, particularly in Western populations, while it has limited influence on the risk of esophageal adenocarcinoma.
吸烟会显著增加罹患食管鳞癌的风险，中度增加罹患食管腺癌的风险。戒烟对不同组织学亚型、潜伏期和地理区域的食管癌风险的影响尚不清楚。
系统检索了 Medline、Embase、Web of Science、Cochrane 图书馆和 ClinicalTrials.gov 中的研究。使用随机效应模型得出风险比（RR）的汇总估计值。使用 Cochran's Q 检验和 I2 统计量来检测异质性。
在 15009 项研究中，有 52 项符合纳入标准。与不吸烟者相比，曾经吸烟者罹患食管鳞癌的风险较低（RR=2.05，95%置信区间[CI]：1.71 至 2.45），而目前吸烟者的 RR 为 4.18（95%CI：3.42 至 5.12）。与目前吸烟者相比，戒烟 5 年以上RR 显著降低（RR=0.59，95%CI：0.47 至 0.75），10 年以上RR 进一步降低（RR=0.42，95%CI：0.34 至 0.51），20 年以上RR 降低更为显著（RR=0.34，95%CI：0.25 至 0.47）。这种风险降低在西方人群中较强，而在亚洲人群中较弱。与不吸烟者相比，曾经吸烟者罹患食管腺癌的风险略低于目前吸烟者（RR=1.66，95%CI：1.48 至 1.85）。与目前吸烟者相比，戒烟后时间依赖性地降低了食管腺癌的风险，戒烟 20 年以上的 RR 为 0.72（95%CI：0.52 至 1.01）。
戒烟时间依赖性地降低了食管鳞癌的风险，尤其是在西方人群中，而对食管腺癌的风险影响有限。
