(Health Day News) -- Many patients diagnosed with lung cancer -- as well as their family caregivers -- continue to smoke even though doing so may jeopardize their recovery and long-term health outcome, says a study sponsored by the U.S. National Cancer Institute.

Researchers report that nearly one in five recently diagnosed lung cancer patients continues to light up, which can make them feel guilty or socially stigmatized.
""The biggest obstacle is fatalism, the belief that it is too late to quit smoking so why bother,"" said Kathryn E. Weaver, study lead author and assistant professor of social sciences and health policy at Wake Forest Baptist Medical Center in Winston-Salem, N.C.
""There are benefits to be gained by quitting that have important implications for survival, response to treatments, and quality of life,"" she said.
The findings point to the need for family support, counseling and medication to help patients and/or family caregivers overcome their addiction and adopt healthy lifestyle choices, said Weaver.
The study was recently published in Cancer Epidemiology, Biomarkers & Prevention.
The researchers looked at 742 cancer patients and caregivers at multiple sites and found that 18 percent of smokers with lung cancer failed to quit after their diagnosis. Smoking is the leading cause of lung cancer.
Among a subset of smokers with colorectal cancer, which is not strongly associated with tobacco use, 12 percent of the patients continued smoking.
An even higher proportion of the patients' family caregivers also kept on smoking -- 25 percent of those caring for lung cancer patients and 20 percent of those caring for colorectal cancer patients, the researchers found.
Most of the caregivers were middle-aged females and were often spouses of the patients. In some cases, both the patient and the caregiver continued smoking.
If family caregivers see the cancer patient quit, they're more likely to quit themselves, Weaver said. But if either the patient or caregiver continues to smoke, it can trigger issues of guilt, stigma or blame, she added.
Continued smoking increases the likelihood of developing a secondary cancer and can interfere with treatment, the researchers say.
Another clinical reason to stop smoking, said Dr. Norman H. Edelman, chief medical officer of the American Lung Association, is that chronic obstructive pulmonary disorder (COPD) usually accompanies lung cancer, making it more difficult to breathe. Continued smoking exacerbates COPD, he said. Also, research has suggested that nicotine may be a co-promoter in generating lung cancer, so continual exposure to nicotine might work against chemotherapy treatments, Edelman said.
Given that more than 80 percent of some 200,000 lung cancer cases diagnosed annually in the United States are smoking-related, he said the complex dynamics of why so many smokers don't quit needs to be better understood.
Even patients highly motivated to stop for good often need substantial support, he added.
Weaver said the stressful period following diagnosis of lung cancer can create a ""teachable moment"" for physicians, nurses and other health care professionals to discuss smoking cessation with the patient and family members, and offer encouragement and resources to quit.
""My long term goal is to develop more effective interventions that can be delivered in the oncology setting, said Weaver.
Janine Cataldo, an assistant professor and researcher in physiological nursing and gerontology at the University of California San Francisco, is developing tools that measure the quality of life and impact of social stigma on lung cancer patients who continue smoking.
""For a smoker to have lung cancer and be unable to quit speaks to the power of nicotine addiction,"" said Cataldo. The average lung cancer patient is 55 years old and typically has tried and failed to quit smoking several times, she added. Continued smoking has serious repercussions for lung cancer patients, she said.
Patients may develop appetite loss, fatigue, cough or coughing up of blood, pain and poor sleep, said Cataldo. Self-esteem suffers too, and anxiety and depression may also develop, she said.
Cataldo is developing a six-month intervention that focuses on three key components: nicotine replacement therapy to ease withdrawal symptoms; a computerized calling system for monthly phone counseling and weekly follow-up; and creation of a smoke-free home environment.
""The immediate benefits of quitting smoking are easier breathing, increased circulation and improved efficacy of cancer treatments,"" said Cataldo. ""People find that once they quit, they have an increased joy of life, no matter how much they believed in the myth that they would miss cigarettes.""