Remco M. van den Berg

Color Fluorescence Ratio for Detection of Bronchial Dysplasia and Carcinoma In situ

Background: Autofluorescence bronchoscopy is more sensitive than conventional bronchoscopy for detecting early airway mucosal lesions. Decreased specificity can lead to excessive biopsy and increased procedural time. Onco-LIFE, a device that combines fluorescence and reflectance imaging, allows numeric representation by expressing red-to-green ratio (R/G ratio) within the region of interest. The aim of the study was to determine if color fluorescence ratio (R/G ratio) added to autofluorescence bronchoscopy could provide an objective means to guide biopsy. Methods: Subjects at risk for lung cancer were recruited at two centers: VU University Medical Centre (Amsterdam) and BC Cancer Agency (Canada). R/G ratio for each site appearing normal or abnormal was measured before biopsy. R/G ratios were correlated with pathology, and a receiver operating characteristic curve of R/G ratio for high-grade and moderate dysplasia was done. Following analysis of the training data set obtained from two centers, a prospective validation study was done. Results: Three thousand three hundred sixty-two adequate biopsies from 738 subjects with their corresponding R/G ratios were analyzed. R/G ratio 0.54 conferred 85% sensitivity and 80% specificity for the detection of high-grade and moderate dysplasia, area under the curve was 0.90, and 95% confidence interval was 0.88 to 0.92. In another 70 different sites that were assessed, κ measurements of agreement of R/G ratios with visual scores and pathology were 0.66 (P < 0.0001) and 0.61 (P < 0.0001), respectively. R/G ratio combined with visual score improved specificity to 88% (95% confidence interval, 0.73-0.96) for high-grade and moderate dysplasia. Conclusion: Color fluorescence ratio can objectively guide the bronchoscopist in selecting sites for biopsy with good pathologic correlation.

Comprehensive CADM1 promoter methylation analysis in NSCLC and normal lung specimens

Methylation-mediated silencing of the tumour suppressor CADM1 has been functionally linked to lung cancer development. We aimed to determine whether CADM1 promoter methylation is a candidate early detection marker for lung cancer. To this end frozen tissue samples of 36 non-small cell lung cancers, 26 corresponding tumour distant normal tissue samples as well as 6 samples of normal lung from non-lung cancer patients were tested for DNA methylation at three different regions within the CADM1 promoter (M1, M5 and M9) using methylation specific PCR followed by methylation specific reverse line blot analysis. Sixty-four percentage of tumour samples tested positive at the M1 region, 47% at M5 and 74% at the M9 region, compared with 65% (M1), 23% (M5) and 46% (M9) of paired normal tissue samples. Methylation of each of these promoter regions was also detected in the majority of non-lung cancer control samples. Dense methylation, defined as methylation at ≥2 promoter regions, was detected in 66% of tumour samples compared with 38% of paired normal tissues and 67% of non-lung cancer control samples. Within the small subgroup of female patients dense methylation was found in all tumour samples but only 22% of paired normal samples. Neither methylation of individual sites nor dense methylation was correlated with disease free survival. In conclusion, CADM1 promoter methylation is a frequent event in NSCLC as well as normal lung, both of lung cancer and non-lung cancer patients. Hence, CADM1 methylation analysis is unlikely to have diagnostic value for the early detection of lung cancer in an unselected population. However, a diagnostic value for selected subjects, such as females, cannot be excluded.

The Finding of Premalignant Lesions is Not Associated with Smoking Cessation in Chemoprevention Study Volunteers

Background and Study Aims: Screening programs for lung cancer may lead to a heightened awareness of the risks of smoking and enhance quitting. The aim of this study was to evaluate whether the participation on a chemoprevention study for premalignant lesions could influence smoking cessation. Methods: Two hundred one volunteers, current (n = 188) and former smokers (n = 13) with more than 20 pack years had been screened for the chemoprevention study. One hundred forty-six of the current smokers at time of chemoprevention study screening have been retrospectively interviewed about their smoking behavior ≥1 year after their first contact for the chemoprevention study. Structured questionnaires were used, and interviews were held by telephone. The quitters at the time of these first interviews were contacted again 4 years after the initial interview about their current smoking behavior. Results: Of the 146 smoking volunteers, 83 were diagnosed with premalignant lesions of the bronchial mucosa and participated in the chemoprevention study, and 63 had no premalignant lesions and were not included in that study. The majority of participants were men: 87 (60%). The mean age of the participants was 52 ± 9 years, and the mean age at which volunteers started smoking was 15 ± 3. Mean number of pack years was 47 ± 27. Ten volunteers in the group without premalignant lesions and 19 in the group with premalignant lesions had quit smoking at time of the first interview. The smoking cessation rate of the total study group was 20%. Univariate logistic regression analysis demonstrated that smoking cessation was only significantly associated with male gender. No significant associations were found between smoking cessation and the finding of premalignant lesions, sex, age, level of addiction, educational level, marital condition, history of cancer/pulmonary diseases, age at start smoking, previous attempts to quit smoking, and motivation to quit smoking. Within the group of subjects who had quit smoking at the time of the first interview, 15 of 29 persons who had stopped smoking at the time of the first interview have reported that participation in the bronchoscopy screening and/or the trial has been of major influence on their decision to stop smoking. Conclusions: A smoking cessation rate of 20% has been found among volunteers for a chemopreventive trial investigating smoking-related premalignant lesions after almost 2 years after initial contact has been found. Volunteers experienced screening and trial participation as having influenced their smoking cessation. Smoking cessation was significantly associated with male gender, whereas the finding of premalignant lesions by bronchoscopy was not.