Influence of Biopsy Technique on Molecular Genetic Tumor Characterization in Non-Small Cell Lung Cancer-The Prospective, Randomized, Single-Blinded, Multicenter PROFILER Study Protocol

Diagnostic performance of cryobiopsy guided by radial-probe EBUS with a guide sheath for peripheral pulmonary lesions

OBJECTIVE

Transbronchial lung cryobiopsy (TBCB) has developed rapidly and has become one of the research hotspots of lung biopsy technology. The present study sought to evaluate the efficacy of TBCB guided by radial-probe EBUS (RP-EBUS) and a guide sheath (GS) without fluoroscopy for peripheral pulmonary lesions.

METHODS

In this retrospective study, McNemar's test was used in order to compare TBCB and transbronchial forceps biopsy (TBFB) in terms of diagnostic performance. A multivariate logistic regression model was designed to explore the association between predictive variables and the diagnostic yield of TBCB.

RESULTS

A total of 168 patients underwent GS-guided RP-EBUS. Of those, 157 had lesions that were visible and 11 had lesions that were not. Of those 157 patients, 24 were excluded because of missing data or an unclear final diagnosis. Therefore, 133 patients underwent RP-EBUS-GS-guided TBFB and TBCB. The pooled diagnostic yield of RP-EBUS-GS-guided TBCB without fluoroscopy was 71.5% (103/144). In 133 patients, the diagnostic yield of TBCB was significantly higher than that of TBFB (77.4% vs. 59.4%; p < 0.05). Multivariate analysis indicated that lesion size and site were independently associated with the diagnostic yield of TBCB (OR = 2.8, p = 0.03 and OR = 4.1, p = 0.01, respectively), although cryoprobe size was not. There was no significant difference between the 1.1-mm cryoprobe and the 1.9-mm cryoprobe in terms of diagnostic performance (78.4% vs. 76.8%; p > 0.05).

CONCLUSIONS

GS-guided RP-EBUS is regarded as a practical option for guiding cryobiopsy, although it may not be able to replace fluoroscopy. Peripheral pulmonary lesions not located in the upper lobes or larger than 30 mm are significantly associated with a higher diagnostic yield of cryobiopsy.

Liquid Biopsy for Biomarker Testing in Non-Small Cell Lung Cancer: A European Perspective

The development of targeted therapies has improved survival rates for patients with advanced non-small cell lung cancer (NSCLC). However, tissue biopsy is unfeasible or inadequate in many patients, limiting biomarker testing and access to targeted therapies. The increasing numbers of established and emerging biomarkers with available targeted treatments highlights the challenges associated with sequential single-gene testing and limited tissue availability. Multiplex next-generation sequencing (NGS) offers an attractive alternative and represents a logical next step, and in cases where the tumour is inaccessible, tissue biopsy yields insufficient tumour content, or when the patient’s performance status does not allow a tissue biopsy, liquid biopsy can provide valuable material for molecular diagnosis. Here, we explore the role of liquid biopsy (i.e., circulating cell-free DNA analysis) in Europe. Liquid biopsies could be used as a complementary approach to increase rates of molecular diagnosis, with the ultimate aim of improving patient access to appropriate targeted therapies. Expert opinion is also provided on potential future applications of liquid biopsy in NSCLC, including for cancer prevention, detection of early stage and minimum residual disease, monitoring of response to therapy, selection of patients for immunotherapy, and monitoring of tumour evolution to enable optimal adaptation/combination of drug therapies.

Cytology samples and molecular biomarker testing in lung cancer-advantages and challenges

This review presents an overview on molecular diagnostic in lung cancer using cytologic samples. Every patient with advanced non-small cell lung cancer (NSCLC) should be tested for targetable driver mutations and gene arrangements. If a mutation is found, this may open an option for targeted therapy. As most of the NSCLC patients in advanced stage of disease are no candidates for surgery, these tests have to be performed on small biopsies or cytology samples. The most common and treatable gene alterations should be tested in every patient: EGFR, ALK, ROS1. A growing number of other genetic changes with targetable mutations may become treatable in the near future. To find patients who might profit from inclusion into clinical studies, relevant additional markers may be tested in an appropriate context. Another important approach for treatment is immunotherapy of lung cancer, which is guided by status of PD-L1 expression on tumour cells. The use of cytology samples carries considerable advantages: often, DNA of high quality is extracted thus enabling easy and precise analysis, and samples may be easily obtained. In case of effusions, effusion fluid seldom is not aspirated for immediate patient relief, so no additional dedicated procedure is needed. Some challenges exist: If the tumour cell count is low, mutations with a low allelic frequency may be missed. In cellblocks formalin-induced DNA, damage may obviate any DNA analysis. In very cellular smears, FISH may be impossible due to massive overlapping of nuclei. Autofluorescence may impede FISH analysis. Although there is no real universal test for genomic profiling for lung cancer, the pathology laboratory must be prepared to offer different assays on different specimens in order to address turnaround time and optimise detections of difficult tumour alterations such as gene fusions. The data from the literature demonstrate that cytology show consistent results, and it is a good alternative for lung cancer molecular testing.