SAN FRANCISCO — An unusual pattern of sudden, effortless smoking cessation in long-term smokers may herald the onset of lung cancer in a small subgroup of patients, researchers reported at the World Conference on Lung Cancer.
It has been well documented that lung cancer patients often stop smoking shortly before their diagnosis, with the assumption that symptoms such as shortness of breath, coughing, or pain create a strong motivation for behavior change.
Now a pilot study suggests that in certain lung cancer patients—even some with long-term smoking histories and significant nicotine addiction—smoking cessation occurs in the absence of symptoms or even a focused effort to quit.
“This has led us to speculate that in some cases, spontaneous smoking cessation may be a presenting feature of lung cancer, possibly caused by tumor secretion of a factor interfering with nicotine addiction,” said Dr. Barbara Campling, a medical oncologist with the University of Pennsylvania in Philadelphia.
In a study conducted at the Philadelphia VA Medical Center, 115 smokers and former smokers diagnosed with lung cancer were compared to 200 smokers and former smokers with prostate cancer (101) or MI (99).
Former smokers with prostate cancer had quit smoking an average of 23 years before their diagnosis; for MI, the average interim was 10 years.
But smoking cessation was a more recent event for lung cancer patients, occurring an average of 2.7 years before diagnosis.
Further comparisons among former smokers revealed striking differences among the three groups.
“In the general population, you would expect that those who succeeded in quitting smoking would be those who smoked less and were less severely addicted,” she said at the meeting sponsored by the International Association for the Study of Lung Cancer. “That is exactly what we found in patients with prostate cancer and myocardial infarction.”
In contrast, current and former smokers with lung cancer had similar levels of cumulative tobacco exposure and identical median scores on a scale measuring severity of addiction, scoring 7 on a scale of 0 (“Didn't even think about it”) to 10 (“The hardest thing I've ever done”).
Surprisingly, many of these lung cancer patients reported they had quit smoking with ease and with no symptomatic “alarm bell” that compelled them to stop.
Among the 55 patients who quit smoking before being diagnosed with lung cancer, 49 (89%) were reportedly asymptomatic at the time.
Nearly a third (17 of 55) reported quitting “with no difficulty” (0 on a scale of 0-7), even though they were moderately to severely addicted to nicotine based on the Fagerström Test for Nicotine Dependence.
“The way some of these patients stop smoking is really quite peculiar,” Dr. Campling said. A typical patient was “someone who had smoked a pack of cigarettes a day for 50 years and wakes up one day and forgets to light a cigarette … [and then] realizes they don't need it anymore.”
Dr. Campling and her associates hope their findings will be followed up with a long-term, prospective study of smokers to identify any unusual patterns of smoking cessation that may precede a diagnosis of lung cancer. In the meantime, she suggested that clinicians pay attention to any highly unusual pattern of smoking cessation in a long-term, heavy smoker, just as they would a sudden loss of appetite.
Dr. Campling and her associates reported no financial disclosures with respect to their study.
'The way some of these patients stop smoking is really quite peculiar.'
Source DR. CAMPLING