Efficacy of bronchoscopic biopsy for the detection of epidermal growth factor receptor mutations and anaplastic lymphoma kinase gene rearrangement in lung adenocarcinoma

[Endobronchial Ultrasound Guided Transbronchial Needle Aspiration for The Diagnosis and Genotyping of Lung Cancer]

背景与目的

超声气管镜针吸活检（endobronchial ultrasound guided tranbronchial needle aspiration, EBUS-TBNA）是临床怀疑肺癌患者的常用活检方式，在肺癌的诊断和分期中有着举足轻重的作用。然而该活检方式在诊断之余是否亦能提供充分的组织完成基因检测尚待研究。本文评价EBUS-TBNA所取得标本进行肺癌诊断及相关基因检测的可行性。

方法

对纵隔淋巴结肿大且临床怀疑肺癌诊断的患者进行EBUS-TBNA活检，所取得的标本进行病理诊断并对其中的非鳞非小细胞肺癌标本进行驱动基因检测。分析其诊断阳性率以及完成基因检测的可行性。

结果

入选377例患者平均单个淋巴结穿刺2.07针，确诊肺癌213例，经EBUS-TBNA诊断率92%。其中表皮生长因子受体（epidermal growth factor receptor, EGFR）基因、间变淋巴瘤激酶（anaplasticlymphoma kinase, ALK）融合基因、以及同时完成两个基因检测的患者分别为84例（90%）、105例（96%）及79例（90%）。单因素分析显示组织基因检测成功率与穿刺淋巴结针数、淋巴结大小及淋巴结部位无关，但与肿瘤病理类型相关。腺癌病理类型的EGFR基因突变及ALK融合基因检测的成功率均高于未分类非小细胞肺癌。

结论

EBUS-TBNA可提供充足的组织对肺癌进行诊断和基因分型。肿瘤病理类型可能是影响基因检测阳性率的因素。

Efficacy of D5F3 IHC for detecting ALK gene rearrangement in NSCLC patients: a systematic review and meta-analysis

We conducted a pooled analysis comparing the efficacy of an immunohistochemistry (IHC) assay using the D5F3 antibody with that of fluorescence in situ hybridization (FISH) for detecting ALK gene rearrangement in NSCLC patients. A total of 32 studies involving 5805 samples were included in this review. Pooled sensitivity for D5F3 IHC was 0.97 (95%CI: 0.93-0.98), specificity was 0.99 (95%CI: 0.98-1.00), PLR was 119.20 (95%CI: 57.79-245.89), NLR was 0.03 (95%CI: 0.02-0.07), DOR was 3526.66 (95%CI: 1344.71-9249.03), and AUROC was 1.00 (95%CI: 0.99-1.00). Meta-regression revealed that specimen type was a source of heterogeneity for specificity, and specimen type and FISH signal distance were sources of heterogeneity in the joint model. Subgroup analysis revealed that sensitivity and specificity were higher when the FISH signal distance standard was ≥ 2 than when it was ≥ 1. Sensitivity was higher for tumor specimens than for cell specimens; specificity was higher for cell specimens than for tumor specimens. In conclusion, the D5F3 IHC assay was nearly as effective as FISH for detection of ALK gene rearrangement in NSCLC patients.

Inconsistent results in the analysis of ALK rearrangements in non-small cell lung cancer

BACKGROUND

Identification of targetable EML4-ALK fusion proteins has revolutionized the treatment of a minor subgroup of non-small cell lung cancer (NSCLC) patients. Although fluorescence in situ hybridization (FISH) is regarded as the gold standard for detection of ALK rearrangements, ALK immunohistochemistry (IHC) is often used as screening tool in clinical practice. In order to unbiasedly analyze the diagnostic impact of such a screening strategy, we compared ALK IHC with ALK FISH in three large representative Swedish NSCLC cohorts incorporating clinical parameters and gene expression data.

METHODS

ALK rearrangements were detected using FISH on tissue microarrays (TMAs), including tissue from 851 NSCLC patients. In parallel, ALK protein expression was detected using IHC, applying the antibody clone D5F3 with two different protocols (the FDA approved Ventana CDx assay and our in house Dako IHC protocol). Gene expression microarray data (Affymetrix) was available for 194 patients.

RESULTS

ALK rearrangements were detected in 1.7 % in the complete cohort and 2.0 % in the non-squamous cell carcinoma subgroup. ALK protein expression was observed in 1.8 and 1.4 % when applying the Ventana assay or the in house Dako protocol, respectively. The specificity and accuracy of IHC was high (> 98 %), while the sensitivity was between 69 % (Ventana) and 62 % (in house Dako protocol). Furthermore, only 67 % of the ALK IHC positive cases were positive with both IHC assays. Gene expression analysis revealed that 6/194 (3 %) tumors showed high ALK gene expression (≥ 6 AU) and of them only three were positive by either FISH or IHC.

CONCLUSION

The overall frequency of ALK rearrangements based on FISH was lower than previously reported. The sensitivity of both IHC assays was low, and the concordance between the FISH and the IHC assays poor, questioning current strategies to screen with IHC prior to FISH or completely replace FISH by IHC.

Feasibility Study of a Novel Navigation System for Biopsy of Peripheral Lesions in the Lungs

A novel system for electromagnetic navigation in bronchoscopy (ENB) to improve peripheral lesion targeting and diagnostic is currently under development, and preliminary tests on a complex phantom are presented in this paper. The system named Transbite is proving to be easy to use, accurate and useful for experienced and beginner users, with precision around 5-9 mm in reaching targets in sub-segmental bronchi where a conventional video-bronchoscope cannot extent. Transbite system consists of a planning and orientation software, a navigation and biopsy forceps, an active marker that is placed on patient chest and an electromagnetic tracking system from the market connected to a computer containing the software. Transbite can be used with any bronchoscopy system, has a short set-up procedure and learning curve.