What are the impacts when a patient with cancer continues to smoke while being treated?

According to a 2014 United States Surgeon General’s report, the list is sobering. It can increase risks for secondary cancers or death. It can impair the effectiveness of cancer treatments. It can even make those treatments more toxic.

Now, researchers from the Medical University of South Carolina are attempting to associate a dollar figure: the financial impact that patients’ continued smoking has on the cost of cancer care. Their study appears in JAMA Network Open, an online-only open access general medical journal from the American Medical Association.

Using data from the same Surgeon General’s report, they developed an economic model that takes into account expected failure rates for patients undergoing first-line treatments for a variety of cancers; how those failure rates differ between smokers and non-smokers; and the costs of further treatment after a first-line therapy fails. They report “a potential $3.4 billion incremental cost of treating cancer failures associated with continued smoking among patients with cancer in the U.S. each year.”

“What’s novel about this study is that it’s taking a look at the economics behind continued smoking in cancer patients,” noted Dr. Vani Nath Simmons, Moffitt Cancer Center researcher and scientific director of its Cancer Center Cessation Initiative grant. The two-year $500,000 project funded through the National Cancer Institute’s (NCI) Cancer Moonshot Initiative will help Moffitt improve its process of providing patients with smoking cessation advice and connections to evidence-based treatment tailored to their specific needs. “We already have a great body of work showing the negative health effects associated with continuing to smoke while being treated for cancer,” said Simmons. “This shows the additional costs in terms of dollars. As we increase attention to cost savings in health care, some of these modifiable behaviors can be overlooked.  This draws attention to what patients can do to impact their health and the costs of care, and underlines the value of institutions ensuring there are resources available to help patients in these efforts.”

But others caution against taking those cost estimates too literally. Dr. Margaret Byrne, an associate member in Moffitt’s Health Outcomes and Behavior Program, holds a Ph.D. in economics.

She said the topic of costs associated with smoking while receiving cancer treatment is important and economic models can be a good approach to getting answers. “But how one sets up the models is critically important. In this study, the development of the model and range of inputs used is untethered from any specific cancer, treatment or population. All model inputs are allowed to take on a very large range of values. For example, first line treatment failure rates for non-smoking patients are allowed to range from 10-90 percent; and the increased risk of failure for smokers is allowed to range from 10-300 percent. Thus, the possible model ‘results’ are extremely broad, and completely dependent on the specific input values selected. Because of this underlying generality, specific results such as those presented in study abstract can be taken out of context, are subject to misinterpretation, and may be potentially misleading.”