The intervention to be studied is a smoking cessation program offered to newly diagnosed cancer patients at their first consultation for treatment at an oncological hospital department.

The theoretical basis for the smoking cessation program is motivational interviewing (MI), an established counselling method previously used in smoking cessation programs as well as in other behaviour change programs. MI is defined as "a directive, client-centred counseling style for eliciting behaviour change by helping clients to explore and resolve ambivalence" (Miller 1983, cited in a Cochrane report by Lindson-Hawley, N et al., 2015). The 2015 Cochrane review concluded that MI may help people to quit smoking, but underlined at the same time that there were huge variations in study quality and intervention implementations. To our knowledge, a MI-based smoking cessation program has to a very limited extent been tried in a hospital setting before.

The program includes a cessation kit with a few samples of different smoking cessation drugs (nicotine replacement therapy) and consists of at least four individual counselling sessions (30-60 min) and follow up as needed during six months with a trained smoking cessation counsellor. Counselling will take place at the hospital premises, in conjunction with scheduled cancer treatment sessions for the patients.

In the current study, two nurses or radiation therapists at each of the included hospitals will receive training in using MI in smoking cessation counselling. The Norwegian Directorate of Health's standard smoking cessation program based on MI will be modified to be appropriate for cancer patients in treatment. The Norwegian Cancer Society (NCS) will be responsible for the training and the adaptation of the program. NCS will cover on average a 50 percent position designated smoking cessation counselling at each cancer ward. Counselling (one to one counselling) will take place in connection with cancer treatment appointments, before or after (preferably before as patients might feel unwell or nauseas after treatment), except for the first appointment that will happen before cancer treatment starts. Each counselling session will last for approximately 30-60 minutes.

Inclusion Criteria:

• Newly diagnosed cancer patients
• Offered radiation, chemo or immuno therapy in a designated hospitals
• Current smokers or recent quitters (within the last six weeks)
• 18 years or older

Exclusion Criteria:

• Survival prognosis less than 12 months
• Suffering dementia or other mental illnesses