By Norra MacReady
SEOUL, SOUTH KOREA -- September 6, 2007 -- Using risk factors to identify candidates for lung cancer screening with autofluorescent bronchoscopy (AFB) is an efficient way of finding the premalignant lesions that are harbingers of squamous cell carcinoma, researchers reported here at the 12th World Conference on Lung Cancer (WCLC).
Mary E. Reid, PhD, Research Scientist, Department of Epidemiology, Roswell Park Cancer Institute, Buffalo, New York, United States, and colleagues screened 350 people chosen for the following risk factors: smoking history of 20 pack-years or more; a history of aerodigestive cancer within the previous 2 years or asbestos-related lung disease; presence of chronic obstructive pulmonary disease (COPD).
All patients underwent an initial AFB examination, with subsequent bronchoscopies performed as indicated. A single investigator performed all of the AFBs, which took place from 1998 through the end of 2006.
A total of 339 patients underwent initial AFB. There were 214 former smokers (62%), 99 current smokers (31%), and 26 people who had never smoked (8%). Of these patients, 222 (66%) were men. The participants had a mean age of 63 years, and a mean smoking history of 46 pack-years. COPD was present in 220 patients (65%), and 140 patients had a history of asbestos-related lung disease.
None of the patients showed evidence of an active lesion at the time of initial screening, said Dr. Reid.
Current smoking was the biggest risk factor for a premalignant lesion by far, with an odds ratio (OR) of 13.3. A past history of smoking came in a distant second, with an OR of 2.7. Presence of COPD was close behind, with an OR of 2.42, and male gender was fourth, with an OR of 1.94.
From the baseline AFB, 179 patients (53%) were diagnosed with metaplastic or higher-grade lesions. A total of 114 patients underwent subsequent AFB examinations; of those people, 71 (62%) were diagnosed with metaplasia or worse. Of the 52 patients who had a third examination, 42 (81%) received a diagnosis of metaplasia or worse.
Baseline AFB detected 58 metaplastic lesions; of those, 28 (48%) persisted and 12 (21%) had progressed on the second AFB. Similarly, of the 26 dysplasias detected at baseline, five (19%) persisted and one (4%) had progressed by the next examination. Eight dysplasias regressed to normal, and 12 to metaplasia. The baseline examination also found five cases of lung cancer or carcinoma in situ.
All in all, "this is an effective way of identifying high-risk patients with premalignant lesions," Dr. Reid concluded.
These findings also suggest that "metaplasia is not simply a transient change to the epithelium," although the natural history of premalignant lesions remains unclear and deserves further study.
[Presentation title: The Prevalence and Persistence of Premalignant Lesions: A Report of a High Risk Lung Cancer Project. Abstract A7-06]
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