Abstract
Background: Tobacco smoking is a leading cause of preventable cancer worldwide. This systematic review aims to synthesize and evaluate the existing literature on the relationship between smoking cessation, smoking reduction, and the risk of cancer, with a particular focus on lung cancer.
Methods: A systematic search of electronic databases was conducted to identify relevant studies published up to the knowledge cutoff date in September 2021. Eight studies meeting the inclusion criteria were selected for analysis. These studies encompassed diverse populations and methodologies, including cohort studies and population- based investigations.
Results: The findings reveal a consistent pattern across the included studies. Smoking cessation emerged as a highly effective strategy for reducing the risk of cancer, particularly lung cancer. Even individuals who quit smoking later in life experienced a substantial decrease in their cancer risk. Additionally, smoking reduction, although less effective than cessation, demonstrated a noteworthy impact, especially among heavy smokers. Reduction in the number of cigarettes smoked per day was associated with a decreased risk of all cancer, smoking-related cancer, and lung cancer. The results of this systematic review underscore the critical importance of smoking cessation as a primary strategy for mitigating cancer risk, aligning with broader public health objectives to reduce tobacco-related harm. While cessation remains the gold standard, smoking reduction can offer a pragmatic approach for those who are unable to quit immediately, particularly heavy smokers. The review also highlights the potential for personalized interventions based on age, smoking history, and histologic subtype to optimize smoking cessation efforts.
Conclusion: Smoking cessation and reduction represent crucial strategies for preventing cancer, particularly lung cancer. Public health campaigns and clinical interventions should prioritize smoking cessation support, emphasizing the long-term benefits of remaining smoke-free. By promoting these measures, we can significantly reduce the burden of tobacco-related cancers and improve public health outcomes. Further research is needed to explore the long- term effects of smoking behavior changes on cancer risk, considering diverse populations and histologic subtypes.

Key words: smoking cessation, Tobacco, smoking, cancer, cancer prevention.