A study sponsored by the US National Cancer Institute shows that one in five lung cancer patients continue to smoke, even after their diagnosis. A number of family caregivers also fail to kick the habit once the person they’ll be caring for is diagnosed with the sometimes deadly disease. The biggest emotional obstacles faced by those who choose to continue smoking are feelings of guilt or social stigmatism.

“The biggest obstacle is fatalism, the belief that it is too late to quit smoking so why bother”, said Kathryn E. Weaver of the Wake Forest Baptist Medical Center in Winston-Salem, North Carolina. “There are benefits to be gained by quitting that have important implications for survival, response to treatments, and quality of life”, she said. In order to be able to quit, patients and care givers both will need the support of their family, medication, counseling, or some combination of the three.

In the study, which was later published in Cancer Epidemiology, Biomarkers & Prevention, examined 742 patients and care givers in multiple locations and found that around 18% of smokers with lung cancer failed to kick the habit post-diagnosis. They also found that only 12% of smokers with colorectal cancer, which isn’t strongly associated with tobacco, continued to smoke after they became diagnosed.