It has been known that many lung cancer patients have stopped smoking before diagnosis, but that has been thought to be due to symptoms that they felt. Now, however, a study suggests that the ability to spontaneously stop may actually be an early sign of lung cancer, without there being any actual symptoms.
The study, published in the March issue of the Journal of Thoracic Oncology, the official journal of the International Association for the Study of Lung Cancer (and which is published by OT‘s publisher, Wolters Kluwer Health), was based on interviews with 115 lung cancer patients from the Philadelphia Veterans Affairs Medical Center, all of whom had been smokers.
Fifty-five (48%) had quit smoking before diagnosis, and only six of those (11%) had experienced symptoms of lung cancer by the time they quit. Patients with lung cancer who quit were as dependent on nicotine, when their smoking was at its highest point, as those who continued to smoke. Yet 31% reported quitting with no difficulty.
For comparison, the researchers, led by Barbara G. Campling, MD, Professor in the Department of Medical Oncology at Thomas Jefferson University, also interviewed patients with prostate cancer and those who had suffered a heart attack. The median interval between quitting smoking and lung cancer diagnosis was 2.7 years vs 24.3 years for prostate cancer and 10 years for a heart attack.
The team—which also included Bradley Collins, PhD; Kenneth Algazy, MD; Robert Schnoll, PhD; and Miu Lam, PhD—speculated, therefore, that spontaneous smoking cessation may be a presenting symptom of lung cancer, possibly caused by tumor secretion of a substance interfering with nicotine addiction.
Dr. Campling noted in a news release that the lung cancer patients often quit smoking with no difficulty, despite multiple previous unsuccessful quit attempts.
“The results should not encourage smokers to continue smoking,” she emphasized. “There is a danger that this study could be misinterpreted as suggesting that heavy smokers should continue smoking. All smokers must be strongly encouraged to stop.”
The simple observation that many patients with lung cancer quit smoking without difficulty before diagnosis has many implications, the team noted in their study. “Recognition of this phenomenon as a presenting symptom of lung cancer could result in earlier diagnosis of this common, highly lethal cancer, which is curable only when diagnosed at an early stage. An understanding of the biological basis of this phenomenon could lead to new strategies for smoking cessation.”