Self-determination Plus Instant Messaging for Smokers With Cancer

Objective: To test the efficacy of a self-determination theory-based intervention plus instant messaging to help smokers with cancer quit smoking. Hypothesis to be tested: Subjects who are allowed to choose their quit schedule and receive regular instant messaging about smoking cessation will show a significantly higher biochemically validated quit rate than those who receive only brief advice to quit immediately. Design and Subjects: An RCT will be conducted to 1448 smokers with cancer attending the outpatient clinics of five major acute care hospitals in Hong Kong for medical follow-up. Instruments: A structured questionnaire will be used to assess subjects\' smoking history and demographic and clinical characteristics. EQ-5D-5L will be used to measure subjects\' quality of life. Interventions: The intervention group will receive brief advice and will be invited to choose their own quit schedules (immediate or progressive) in the outpatient clinics. They will receive instant messaging about smoking cessation during the first 6-month follow-up period. The control group will receive brief advice to quit smoking immediately in the outpatient clinics, and will receive a placebo intervention during the first 6-month follow-up period. Subjects in both groups will receive leaflets on smoking cessation.