Clinical Trials and the Need to Incorporate Smoking Habits

Researchers at the Roswell Park Cancer Institute believe that cancer studies should take into account the tobacco and smoking habits of participants-something that rarely happens. Whether a trial participant uses tobacco products can affect cancer treatment, say the group of investigators.

Graham W. Warren, assistant professor in the department of radiation medicine at Roswell Park Cancer Institute, and colleagues assessed tobacco use in patients that were enrolled on 155 ongoing clinical trials. They found that most cooperative groups that coordinate these trials do not take smoking into account.

“Failure to incorporate standardized tobacco assessments into NCI-funded cooperative-group clinical trials will limit the ability to provide evidence-based cessation support and will limit the ability to accurately understand the precise effect of tobacco use on cancer treatment outcomes,” write the study authors.

Their research is published in the Journal of Clinical Oncology. The study is a collaboration with the psychiatry department at the Yale Cancer Center, the Hollings Cancer Center at the Medical University of South Carolina and the M.D. Anderson Cancer Center in Texas.

Smoking can cause cancer and has adverse effects on cancer patients, hindering treatment, making surgery more complicated, and lowering overall survival. Systematic integration of smoking cessation into oncology practice and incorporation of tobacco-use data from clinical trial participants has been proposed but is not entrenched into common practice.

“Tobacco use during cancer therapy reduces the effectiveness of treatments, increases the toxicity of those treatments, and ultimately causes more people to die from their cancer,” said Warren. “The lack of evidence-based tobacco assessment and cessation support limits our ability to accurately assess how tobacco use may affect clinical-trial outcomes and survival.”

Warren and colleagues assessed smoking patterns among patients enrolled in 155 National Cancer Institute (NCI) cooperative-group program clinical trials, making this research prospective, rather than retrospective. More than 100,000 patients are enrolled in these trials in various different tumor indications.

The researchers found that 45 of the 155 trials (29%) assess tobacco use. Only 32 specifically address current cigarrete use. Only 10 trials assess both current and prior tobacco use, but do not go into the detail of defining “tobacco use.” According to the study, none of the trials assessed the interest of participants to quit smoking or tobacco use in general, nor do the trials specify support smoking cessation. Only seven trials (4.5%) evaluated the smoking habits of patients as part of trial follow-up.

“Patients enrolled in cutting-edge research studies may not be receiving support to help them stop using tobacco. Evidence shows that cessation of tobacco use reduces incidence of heart disease and pulmonary disease and may improve cancer control,” Warren added.

The authors argue that incorporating a patient’s smoking history is important not only in patients with cancers that have a direct cause and effect of smoking such as lung and head and neck cancers, but for all tumor types. One important reason is smoking is known to be correlated with poor compliance with cancer treatment, according to three recent studies of breast cancer patients. Warren and colleagues believe that guidelines to monitor current and historic smoking patterns can be easily incorporated into clinical trial protocols. “Oncology research and patients enrolled in research trials may benefit from comprehensive assessment of tobacco status and subsequent increased knowledge about the effects of tobacco on treatment outcome,” the researchers conclude.

Reference

1. Peters EN, Torres E, Toll BA, et al. Tobacco Assessment in Actively Accruing National Cancer Institute Cooperative Group Program Clinical Trials. 2012 June 11. [Epub ahed of print]