Smoking Relapse Prevention in Patients With Cancer

Effectiveness of a Cognitive Behavioral Therapy-Based Smoking Relapse Prevention Intervention Among Patients With Cancer at a Hospital in Vietnam

This randomized controlled trial will evaluate whether adding one-session structured cognitive behavioral therapy (CBT)-based relapse-prevention counseling to standardized brief relapse-prevention counseling improves smoking abstinence among patients with cancer who smoked cigarettes at diagnosis and have remained completely abstinent from diagnosis until enrollment. After written consent and baseline assessment, all participants will receive the same standardized brief relapse-prevention counseling. Participants will then be randomly assigned 1:1 to no additional study CBT or to one additional structured CBT-based relapse-prevention session. Follow-up will continue for 3 months after randomization at Campus 3 of Vietnam National Cancer Hospital in Hanoi, Vietnam.

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:

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

Exclusion Criteria:

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