Print this page Close window


Largest Such Study Finds Smoking Increases Risk of Developing Second Smoking-Related Cancer

 

Authors

  1. Brophy Marcus, Mary

Article Content

Lung, bladder, kidney, and head and neck cancer survivors who smoked before their first cancer diagnosis have up to a five-times higher risk of developing a second smoking-related cancer compared with survivors who never smoked, a large study has shown.

  
Figure. No caption a... - Click to enlarge in new windowFigure. No caption available.

For the study, published online ahead of print in the Journal of Clinical Oncology (doi.10.1200/JCO.2014.56.8220), a team led by Meredith S. Shiels, PhD, MHS, a research fellow in the Infections and Immunoepidemiology Branch of the National Cancer Institute, analyzed data from five large prospective epidemiologic cohort studies that included 15,084 patients: 2,552 with stage 1 lung cancer; 6,386 with bladder cancer; 3,179 with kidney cancer; and 2,967 with head and neck cancers.

 

The five studies that the data were drawn from were the following:

 

* National Institutes of Health-AARP Diet and Health Study;

 

* Agricultural Health Study;

 

* Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study;

 

* Iowa Women's Health Study; and

 

* Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

 

 

Shiels noted in an interview that prior to this research, most of the data on smoking and risk of second cancers among cancer survivors involved smaller studies. "Our study is the largest to date to examine these associations, and the first I'm aware of to look at prediagnostic smoking behaviors and second cancer risk among bladder and kidney cancer survivors," she said.

 

A total of 866 second primary smoking-associated cancers were diagnosed among the survivors, and those who smoked 20 or more cigarettes a day prior to their cancer diagnoses had an up to five-fold higher risk of developing a second smoking-associated cancer compared with survivors of the same cancers who never smoked.

 

* The findings also showed, more specifically, that in those who smoked cigarettes before their first cancer diagnosis:

 

* Stage I lung cancer survivors were 3.3 times more likely to develop a second cancer;

 

* Bladder cancer survivors were 3.7 times more likely to develop a second cancer;

 

* Head and neck cancer survivors were 4.5 times more likely to develop a second cancer; and

 

* Kidney cancer survivors were 5.3 times more likely to develop a second cancer.

 

 

There was still an increased risk for those who smoked fewer than 20 cigarettes a day or who had quit before their first cancer diagnosis compared with never-smokers, but the risks dropped the longer it had been since quitting.

 

New Light

Asked for his perspective for this article, Damon Vidrine, DrPH, MS, Associate Professor of Behavioral Science at the University of Texas MD Anderson Cancer Center, said the study sheds some new light on smoking-related second cancers.

 

"We probably suspected this would be the case, but to my understanding, this is first time we've seen empirical evidence that shows it. I think it's meaningful. It certainly adds to our understanding that smoking is bad and that it is not site specific. It affects sites all over the body," he said.

 

The authors concluded their study by noting that a recent survey of American Society of Clinical Oncology members found that only 58 percent of providers always advise their patients to quit smoking and only 39 percent usually provide treatment or refer patients for treatment for tobacco dependence. Yet, research suggests cigarette smoking is still common in cancer survivors, even among those diagnosed with tobacco-related cancers. Shiels and her 13 coauthors write that this may be because patients do not realize they are at a higher risk for complications, second cancers, and death if they keep smoking.

 

"For those currently smoking at the time of diagnosis, there is still a lot to be gained from quitting," said Vidrine, who added that there is evidence that suggests that quitting at the time of diagnosis increases survival and decreases adverse treatment outcomes.

 

Shiels noted that the number of cancer survivors in the U.S. is growing due to increased survival after many cancer diagnoses, and understanding of risk factors for second cancers is therefore crucial.

 

"We've known for 50 years that smoking causes cancers-there's a huge body of important literature showing that. So it's really important for health care providers to emphasize in general that anybody who is a smoker can benefit from quitting, including cancer survivors, given the increased risk of developing a second smoking-related cancer."

 

Graham Warren MD, PhD, Chair of ASCO's Tobacco Cessation Subcommittee, said in a statement: "As doctors, we want to give our patients the best chance at long-term survival as possible. This study is a reminder for us to aggressively support and encourage tobacco cessation at every step of the way, and should be a wake-up call for all smokers to take the necessary steps to quit."

 

Resources

Stephanie Land, PhD, Director of the NCI's Tobacco Control Research Branch and Behavioral Research Program, said that doctors can help patients by providing counseling and cessation medication, or by suggesting they call 1-800-QUIT-NOW, or visit http://www.smokefree.gov, or similar resources.

 

In addition, information from ASCO notes that the Society is committed to educating its members and providing resources to help patients quit using tobacco. For example, the Society has a policy statement that specifically urges integrating tobacco cessation into clinical care (OT 8/25/13 issue), as well as a detailed guide to help patients quit using tobacco. All the resources are available at http://www.asco.org/tobaccocessationguide.