Smoking Relapse Prevention in Patients With Cancer

Smoking cessation after a cancer diagnosis is clinically important, but initial abstinence may not be sustained. This study is a randomized, two-arm, parallel-group superiority trial evaluating the incremental effect of structured CBT-based relapse-prevention counseling when added to standardized brief relapse-prevention counseling. Eligible participants smoked cigarettes at cancer diagnosis and have remained completely abstinent, without even a puff, from diagnosis until enrollment.

After eligibility confirmation, written informed consent, and baseline assessment, every enrolled participant will receive one standardized individual face-to-face brief relapse-prevention counseling session lasting approximately 3-5 minutes, adapted from the 5A framework for people who are already abstinent. Only after this common counseling is completed will the SNOSE allocation envelope be opened and the participant randomized 1:1. The control arm receives no additional study CBT. The intervention arm receives one additional individual structured CBT-based relapse-prevention session lasting approximately 20-30 minutes.

A participant randomized to the intervention arm may decline the CBT session without being reassigned or rerandomized. The refusal and reason, if provided, will be recorded; outcome follow-up will continue if the participant agrees, and the participant will remain analyzed in the originally randomized arm under ITT.

Participants will be followed for 3 months after randomization. The primary outcome is self-reported 7-day point-prevalence cigarette abstinence at Month 3. CSS-21 and a separate nicotine-withdrawal assessment are administered only at Month 3. The study will enroll the prespecified target of 498 participants (249 per arm).

Inclusion criteria

• Aged 18 years or older.
• Diagnosed with cancer.
• Was smoking combustible cigarettes at the time of cancer diagnosis.
• Has remained completely abstinent from cigarette smoking from the time of cancer diagnosis until study enrollment, without smoking even a puff.
• Provides written informed consent to participate in the study.

Exclusion criteria

• Have a medical, psychiatric, cognitive, hearing, speech, or other condition that prevents effective communication or meaningful participation in the counseling intervention or study assessments.
• Are not expected to be contactable or able to complete the planned follow-up assessments.
• Are currently using other combustible tobacco products, such as waterpipe tobacco, shisha/hookah, cigars, or pipes.
• Are currently participating in another structured smoking-cessation intervention or clinical trial that could materially affect the study outcomes.