Simple advice has a small effect on cessation rates. Assuming an unassisted quit rate of 2 to 3%, a brief advice intervention can increase quitting by a further 1 to 3%. Additional components appear to have only a small effect, though there is a small additional benefit of more intensive interventions compared to very brief interventions.
Brief physician-initiated quit-smoking strategies for clinical oncology settings: a trial coordinated by the Eastern Cooperative Oncology Group.
Although tobacco use by cancer patients increases the risk of relapse, diminishes treatment efficacy, and worsens quality of life, about one third of patients who smoked before their diagnosis continue to smoke. Because patients have regular contact with oncologists, the efficacy of a physician-based smoking cessation treatment was evaluated.
                Cancer patients (n = 432) were randomly assigned to either usual care or a National Institutes of Health (NIH) physician-based smoking intervention. The primary outcome was 7-day point prevalence abstinence at 6 and 12 months after study entry.
                At the 6-month follow-up, there was no significant difference in quit rates between the usual care (11.9%) and intervention (14.4%) groups, and there was no significant difference between the usual care (13.6%) and intervention (13.3%) groups at the 12-month follow-up. Patients were more likely to have quit smoking at 6 months if they had head and neck or lung cancer, began smoking after the age of 16, reported at baseline using a cessation self-help guide or treatment in the last 6 months, and showed greater baseline desire to quit. Patients were more likely to have quit smoking at 12 months if they smoked 15 or fewer cigarettes per day, had head and neck or lung cancer, tried a group cessation program, and showed greater baseline desire to quit. Finally, there was greater adherence among physicians to the NIH model for physician smoking treatment for patients in the intervention versus the usual care group.
                While training physicians to provide smoking cessation treatment to cancer patients can enhance physician adherence to clinical practice guidelines, physician smoking cessation interventions fail to yield significant gains in long-term quit rates among cancer patients.