Alcohol Drinking Cessation and the Risk of Laryngeal and Pharyngeal Cancers: A Systematic Review and Meta-Analysis

Objective
To evaluate the effect of alcohol cessation on the risk of developing laryngeal and pharyngeal cancers, combining available evidence in the scientific literature in a meta-analysis.
Methods
A systematic literature review was conducted, and a meta-analysis was applied on the retrieved studies. The generalised least squares method was used to estimate the trend from dose-response data to assess changes in the risks of laryngeal and pharyngeal cancers after drinking cessation.
Results
A total of 9 case-control studies were included in the meta-analysis (4 and 8 estimates for laryngeal and pharyngeal cancers, respectively). On average, alcohol drinking cessation was associated with a 2% yearly reduction in the risk of developing laryngeal and pharyngeal cancers. There was a considerable heterogeneity between the studies of pharyngeal cancer, but this was mostly due to two studies. The increased risk of laryngeal and pharyngeal cancers caused by alcohol was reversible; the time periods until the risks became equal to those of never drinkers were 36 (95% CI 11–106) and 39 (95% CI 13–103) years, respectively. Moreover, 5 years of drinking cessation was associated with a reduction of around 15% in the alcohol-related elevated risk of laryngeal and pharyngeal cancers.
Conclusion
Although a long time period is required to completely eliminate the alcohol-related elevated risk of laryngeal and pharyngeal cancers, a substantial risk reduction can be seen in the short term (5–10 years), and drinking cessation should therefore be encouraged to reduce the incidence of these cancers.

研究目的：通过荟萃分析（meta-analysis）整合现有科学文献中的证据，评估戒酒行为对喉癌及咽癌发病风险的影响。
研究方法：本研究开展系统文献回顾，并对检索到的研究进行荟萃分析。采用广义最小二乘法（generalised least squares）从剂量反应数据中估算趋势，以评估戒酒后人喉癌与咽癌发病风险的变化。
研究结果：本次荟萃分析共纳入9项病例对照研究（case-control studies），其中喉癌、咽癌相关的效应量估计值分别为4项和8项。平均而言，戒酒可使喉癌与咽癌的发病风险每年降低2%。咽癌相关研究间存在显著异质性，该异质性主要源于两项研究。酒精暴露所致的喉癌与咽癌发病风险升高具有可逆性：当发病风险降至与终生不饮酒者相当的水平时，所需的戒酒时长分别为36年（95%置信区间[CI]：11~106年）与39年（95%CI：13~103年）。此外，戒酒5年即可使酒精相关喉癌与咽癌的升高风险降低约15%。
研究结论：尽管完全消除酒精相关喉癌与咽癌的升高风险需要较长时长，但在短期（5~10年）内即可观察到风险的显著降低，因此应倡导戒酒以降低这两类癌症的发病率。