A scientific report published on September 24, 2015 in the EBioMedicine journal by researchers from the Harvard T.H. Chan School of Public Health indicated that for people who smoke, there is nearly double the chance of developing small cell cancer of the lung when the patient has already been diagnosed with COPD compared to smokers who did not suffer from COPD.

COPD, also known as chronic obstructive pulmonary disease, is a condition that mainly affects the airways of the lungs and is a progressive illness that features cough, wheezing, tightness in the chest, the production of large amounts of thick phlegm, and shortness of breath. The main cause of COPD is smoking, although other factors such as prolonged exposure to chemical fumes, air pollution, or dust can cause the disease as well.

Small cell carcinoma is a cancer of the lungs that is considered the deadliest form of lung cancer, as it has a very low survival rate and it does not respond to the usual treatment methods of surgery, radiation therapy, and chemotherapy. Small cell cancer of the lung is not as common as other lung cancers, and while patients with the disease often respond to treatment at the onset of their diagnosis, the cancer often recurs within a year.  Those with extensive small cell cancer of the lung survive only 9-11 months following the diagnosis of the disease.

What researchers ultimately are seeking to discover is whether or not the early treatment of COPD can make a difference between patients developing small cell cancer of the lung or avoiding it. To this end, researchers in the study evaluated 24 previous case-controlled studies gleaned from the International Lung Cancer Consortium. The studies included 4,346 participants who had small cell carcinoma of the lung and 37,942 participants who did not have small cell cancer. Information about the client’s vital statistics, including smoking history, was among the statistics used in the study.

According to the study:

• The risk of getting small cell carcinoma of the lungs sharply increased up to 50 pack-years of smoking, and increased less so after that. People who had smoked for 20 pack-years were more than 4 times as likely to develop small cell cancer of the lungs, while people with an 80 pack-year history had a 70-fold increase in developing small cell cancer of the lungs when compared to people who did not smoke.
• Smokers who had COPD had a 1.86 times greater risk of developing small cell carcinoma of the lungs as did smokers who did not have COPD.
• Those with small cell cancer of the lungs and who smoked had COPD 8 percent of the time.