Preinvasive Endobronchial Lesions: Lung Cancer Precursors and Risk Markers?

White light, autofluorescence and narrow-band imaging bronchoscopy for diagnosing airway pre-cancerous and early cancer lesions: a systematic review and meta-analysis

BACKGROUND

We aimed to summarize the diagnostic accuracy of white light bronchoscopy (WLB) and advanced techniques for airway pre-cancerous lesions and early cancer, such as autofluorescence bronchoscopy (AFB), AFB combined with WLB (AFB + WLB) and narrow-band imaging (NBI) bronchoscopy.

METHODS

We searched for eligible studies in seven electronic databases from their date of inception to Mar 20, 2015. In eligible studies, detected lesions should be confirmed by histopathology. We extracted and calculated the 2×2 data based on the pathological criteria of lung tumor, including high-grade lesions from moderate dysplasia (MOD) to invasive carcinoma (INV). Random-effect model was used to pool sensitivity, specificity, diagnostic odds ratio (DOR) and the area under the receiver-operating characteristic curve (AUC).

RESULTS

In 53 eligible studies (39 WLB, 39 AFB, 17 AFB + WLB, 6 NBI), diagnostic performance for high-grade lesions was analyzed based on twelve studies (10 WLB, 7 AFB, 7 AFB + WLB, 1 NBI), involving with totally 2,880 patients and 8,830 biopsy specimens. The sensitivity, specificity, DOR and AUC of WLB were 51% (95% CI, 34-68%), 86% (95% CI, 73-84%), 6 (95% CI, 3-13) and 77% (95% CI, 73-81%). Those of AFB and AFB + WLB were 93% (95% CI, 77-98%) and 86% (95% CI, 75-97%), 52% (95% CI, 37-67%) and 71% (95% CI, 56-87%), 15 (95% CI, 4-57) and 16 (95% CI, 6-41), and 76% (95% CI, 72-79%) and 82% (95% CI, 78-85%), respectively. NBI presented 100% sensitivity and 43% specificity.

CONCLUSIONS

With higher sensitivity, advanced bronchoscopy could be valuable to avoid missed diagnosis. Combining strategy of AFB and WLB may contribute preferable diagnosis rather than their alone use for high-grade lesions. Studies of NBI warrants further investigation for precancerous lesions.

A Randomized Phase IIb Trial of myo-Inositol in Smokers with Bronchial Dysplasia

Previous preclinical studies and a phase I clinical trial suggested that myo-inositol may be a safe and effective lung cancer chemopreventive agent. We conducted a randomized, double blind, placebo-controlled phase IIb study to determine the chemopreventive effects of myo-inositol in smokers with bronchial dysplasia. Smokers with ≥1 site of dysplasia identified by autofluorescence bronchoscopy-directed biopsy were randomly assigned to receive oral placebo or myo-inositol, 9 g once a day for 2 weeks, and then twice a day for 6 months. The primary endpoint was change in dysplasia rate after 6 months of intervention on a per-participant basis. Other trial endpoints reported herein include Ki-67 labeling index, blood and bronchoalveolar lavage fluid (BAL) levels of proinflammatory, oxidant/antioxidant biomarkers, and an airway epithelial gene expression signature for PI3K activity. Seventy-four (n = 38 myo-inositol and n = 36 placebo) participants with a baseline and 6-month bronchoscopy were included in all efficacy analyses. The complete response and the progressive disease rates were 26.3% versus 13.9% and 47.4% versus 33.3%, respectively, in the myo-inositol and placebo arms (P = 0.76). Compared with placebo, myo-inositol intervention significantly reduced IL6 levels in BAL over 6 months (P = 0.03). Among those with a complete response in the myo-inositol arm, there was a significant decrease in a gene expression signature reflective of PI3K activation within the cytologically normal bronchial airway epithelium (P = 0.002). The heterogeneous response to myo-inositol suggests a targeted therapy approach based on molecular alterations is needed in future clinical trials to determine the efficacy of myo-inositol as a chemopreventive agent. Cancer Prev Res; 9(12); 906-14. ©2016 AACR.

Low Prevalence of High-Grade Lesions Detected With Autofluorescence Bronchoscopy in the Setting of Lung Cancer Screening in the Pan-Canadian Lung Cancer Screening Study

BACKGROUND

Lung cancer screening with low-dose CT (LDCT) scan has been demonstrated to reduce lung cancer mortality. Preliminary reports suggested that up to 20% of lung cancers may be CT scan occult but detectable by autofluorescence bronchoscopy (AFB). We evaluated the prevalence of CT scan occult, invasive, and high-grade preinvasive lesions in high-risk participants undergoing screening for lung cancer.

METHODS

The first 1,300 participants from seven centers in the Pan-Canadian Early Detection of Lung Cancer Study who had ≥ 2% lung cancer risk over 5 years were invited to have an AFB in addition to a LDCT scan. We determined the prevalence of CT scan and AFB abnormalities and analyzed the association between selected predictor variables and preinvasive lesions plus invasive cancer.

RESULTS

A total of 776 endobronchial biopsies were performed in 333 of 1,300 (25.6%) participants. Dysplastic or higher-grade lesions were detected in 5.3% of the participants (n = 68; mild dysplasia: n = 36, moderate dysplasia: n = 25, severe dysplasia: n = 3, carcinoma in situ [CIS]: n = 1, and carcinoma: n = 4). Only one typical carcinoid tumor and one CIS lesion were detected by AFB alone, for a rate of CT scan occult cancer of 0.15% (95% CI, 0.0%-0.6%). Fifty-six prevalence lung cancers were detected by LDCT scan (4.3%). The only independent risk factors for finding of dysplasia or CIS on AFB were smoking duration (OR, 1.05; 95% CI, 1.02-1.07) and FEV₁ percent predicted (OR, 0.99; 95% CI, 0.98-0.99).

CONCLUSIONS

The addition of AFB to LDCT scan in a high lung cancer risk cohort detected too few CT occult cancers (0.15%) to justify its incorporation into a lung cancer screening program.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00751660; URL: www.clinicaltrials.gov.