Trajectory of smoking behaviour during the first 6 months after diagnosis of lung cancer: A study from Taiwan.

AIMS To identify different classes of change pattern/ trajectory of tobacco smoking behaviour after diagnosis of lung cancer using multi-wave data and to explore factors associated with the class membership. DESIGN This is a multi-wave observational study. METHODS Smoking behaviour data were collected at diagnosis and then every month for 6 months from 133 newly diagnosed people with lung cancer who had recently quit smoking or continued to smoke at diagnosis. These patients were recruited from three medical centres and data were collected from May 2014 to January 2017. Smoking behaviour was assessed based on patients' self-reports on whether they smoked during the last month (yes/no) for a total of seven times. Mixture latent Markov model and logistic regression were used to analyse data. RESULTS Two latent classes of smoking trajectory were identified among recent quitters or current smokers of people with lung cancer, namely "perseverance for abstinence" and "indecisive for abstinence." Patients who were younger age (OR = 0.95, p = 0.026), exposure to second-hand smoke (OR = 3.35, p = 0.012) and lower self-efficacy for not smoking (OR = 0.96, p = 0.011) were more likely to belong to the class of "indecisive for abstinence." CONCLUSIONS Heterogeneous classes of smoking trajectory existed in newly diagnosed people with lung cancer. The risk factors associated with a less favourable smoking trajectory can be incorporated into tailored smoking-cessation programs for patients newly diagnosed with lung cancer. IMPACT The dynamic trajectory of smoking behaviour had not been adequately explored among newly diagnosed people with lung cancer. Two classes of smoking trajectory and the predictors associated with the class membership were identified. These findings suggest that the diagnosis of cancer is a teachable moment for smoking cessation. Patients with younger age, lower self-efficacy of not smoking and exposure to second-hand smoke at home need special attention.