Bimodality screening for lung and oral cancers

This study had 3 specific objectives (1) To compare the efficacy of spiral CT and autofluorescence bronchoscopy (AFB), individually or in combination, in identifying the PMLs and cancers of the lung, (2) To follow up baseline PMLs identified on AFB and to analyze the progression rates and risk factors associated with the progression of these lesions to a higher grade and (3) To compare the efficiency of autofluorescence light exam (AFE) to conventional white light exam (WLE) in detecting the PMLs and cancers of the oral cavity.;A total of 205 patients at high risk of lung cancer were screened at baseline with sputum cytology, X-ray, CT-scan and AFB. Patients with abnormal baseline findings were followed up using CT scan and AFB. All abnormal looking lesions were biopsied and a control biopsy was also obtained. Repeat AFB procedures were performed on 124 patients (average 2.6 AFB/patient). A total of 335 baseline lesions (139 benign, 139 metaplasia and 57 dysplasia), were followed up with repeat biopsies for an average of 16 months after their first AFB. The efficiency of AFB and CT scan, individually and in combination was evaluated and compared to X-ray and sputum cytology. The progression rates and risk factors of progression for the baseline PMLs were evaluated. Based on the auto-fluorescence technique that was used for lung screening an auto-fluorescence prototype was designed for oral cavity and oropharyngeal screening. The entire oral cavity was examined by WLE followed by AFE. All areas that looked abnormal on WLE and/or AFE were biopsied and a control biopsy was also obtained. The efficiency of WLE in detecting oral pre-malignant lesions and cancers was compared to the combination of WLE and AFE.;Overall, 20 lung cancers/CIS were diagnosed in the lung cancer screening cohort in the first four years of follow up. Of these, 7 cancers/CIS were diagnosed at baseline, 4 within one year of follow up and 9 cancers between years 2 and 4. Our results showed that on individual comparison, CT scan and AFB had much higher relative sensitivity than X-ray and sputum cytology, respectively. The combination of CT scan and AFB had almost two and half times better relative sensitivity than the combination of X-rays and sputum cytology, for diagnosing pre-malignant and malignant lung lesions. Also, our follow up on PMLs showed that the metaplasia, low grade dysplasia and high grade dysplasia progressed at a rate of 1.5%, 2.6% and 5.3%, respectively. Heavier smokers and current smokers were at the greatest risk for their baseline lesions progressing to a higher grade. Compared to never smokers, the risk of progression of baseline benign lesions increased by 2.5 times and 7 times in former and current smokers, respectively. Similarly, the risk of progression of existing PMLs was more than two and half times in heavier smokers, even when compared to lighter smokers. Patients who presented with more than two PMLs at baseline AFB had twice the risk of progression, compared to patients with one baseline PML. In the oral cancer screening study, the addition of AFE to WLE increased the relative sensitivity by 83% for identifying low grade lesions, by 47% for high grade lesions, and by 45% for cancers, compared to WLE alone. Of the 68 additional biopsies obtained because of the addition of AFE, 12 biopsies (18%) ended up being high grade lesions or cancers (4 moderate dysplasia, 4 CIS and 4 cancers).;The combination of AFB and CT scan shows a greater efficiency in diagnosing lung cancers compared to any of the screening tests used individually. Even low grade lesions like metaplasia have ability to progress to an invasive lung cancer. Current and heavy smoking and number of baseline PMLs influence the progression rate of the baseline lesions. Similar to the lung, the addition of auto-fluorescence technique to conventional visual oral exam will be able to greatly improve the sensitivity in identifying PMLs and cancers of oral cavity. (Abstract shortened by UMI.).