When data from recent quitters and current smokers were compared, significant differences were found in risk of death among patients with mouth/pharynx cancer (hazard ratio [HR], 0.63; 95% CI, 0.49-0.81), lung cancer (HR, 0.90; 95% CI, 0.81-0.99) and thyroid cancer (HR, 0.33; 95% CI, 0.14-0.75).
When results were weighted according to cancer site distribution in Asia (HR, 0.86; 05% CI; 0.79-0.94) or in the world (HR, 0.87; 95% CI, 0.79-0.96), results were similar.
Dr Tabuchi noted that “harm of tobacco smoking is universal,” so these results should be considered regardless of geography and variety of cancer.
Of recent quitters, 85.1% ceased smoking within 1 year prior to cancer diagnosis. When this majority subset of recent quitters was compared to current smokers, the survival benefit was almost exactly the same, suggesting intervention for smoking at diagnosis could have a meaningful impact on survival.
“Since there is little difference in smoking duration between those who quit shortly before diagnosis and those who quit promptly after diagnosis, the findings from recent quitters may also be applicable to prompt post-diagnostic quitters,” wrote the authors.
“…this has a clinical perspective, suggesting a reversible effect of smoking in cancer patients; in other words, the present study indicates that patients who stop smoking immediately after cancer diagnosis may be able to decrease their risk of death, although this was an observational study and intervention is necessary to test this hypothesis.”
Intervention studies could address whether prompt cessation of smoking upon diagnosis of cancer improves survival and decreases mortality risk.
- Tabuchi T, Goto A, Ito Y, Fukui K, Miyashiro I, Shinozaki T. Smoking at the time of diagnosis and mortality in cancer patients: what benefit does the quitter gain? Int J Cancer. 2017 Jan 10. doi: 10.1002/ijc.30601 [Epub ahead of print]