The Association Between Smoking Status and Breast Cancer Recurrence: A Systematic Review

PURPOSE: To determine whether smoking status (active/passive) affects recurrence events after breast cancer (BC) diagnosis among women. METHODS: A comprehensive literature search of MEDLINE, Cochrane Central, EMBASE, and Web of Science databases on smoking status and BC outcomes retrieved 5,940 articles. After reviewing the inclusion and exclusion criteria, we selected 14 articles for a full review and synthesis. RESULTS: Five studies were cohort retrospective, 6 were case-control, 2 were prospective cohort studies, and 1 was a secondary analysis of a randomized control trial. Among the 8 articles that focused on active smoking, 6 showed an increased risk of BC recurrence, and 2 showed no evidence of such an association. Studies that examined former smokers found little evidence of an increased risk of BC recurrence. This association may be dose-dependent. CONCLUSION: Given the current evidence, although limited, active smokers should quit smoking after BC diagnosis as trends indicate a positive association between active smoking and BC recurrence. More robust evidence is needed to assess such associations and examine the outcomes of quitting smoking in such patients.