Diffuse Lung Metastases in EGFR-Mutant Non-Small Cell Lung Cancer

FDG PET/CT in a Case of Lung Adenocarcinoma With Diffuse Cavitary Intrapulmonary Metastases

ABSTRACT

We describe FDG PET/CT findings in a case of lung adenocarcinoma with diffuse cavitary intrapulmonary metastases at initial diagnosis. High-resolution CT of the chest showed the primary solid tumor in the right upper lobe and numerous cavitating metastases ranging from a few millimeters to 1 cm in the bilateral lungs. FDG PET/CT showed intense activity of the primary tumor, diffuse activity of the lung metastases, and hypermetabolic metastases in the mediastinal lymph nodes and bones. Familiarity with this atypical intrapulmonary metastatic pattern of lung cancer may be helpful for the diagnosis and differential diagnosis.

Propagated Circulating Tumor Cells Uncover the Potential Role of NFκB, EMT, and TGFβ Signaling Pathways and COP1 in Metastasis

Circulating tumor cells (CTCs), a population of cancer cells that represent the seeds of metastatic nodules, are a promising model system for studying metastasis. However, the expansion of patient-derived CTCs ex vivo is challenging and dependent on the collection of high numbers of CTCs, which are ultra-rare. Here we report the development of a combined CTC and cultured CTC-derived xenograft (CDX) platform for expanding and studying patient-derived CTCs from metastatic colon, lung, and pancreatic cancers. The propagated CTCs yielded a highly aggressive population of cells that could be used to routinely and robustly establish primary tumors and metastatic lesions in CDXs. Differential gene analysis of the resultant CTC models emphasized a role for NF-κB, EMT, and TGFβ signaling as pan-cancer signaling pathways involved in metastasis. Furthermore, metastatic CTCs were identified through a prospective five-gene signature (BCAR1, COL1A1, IGSF3, RRAD, and TFPI2). Whole-exome sequencing of CDX models and metastases further identified mutations in constitutive photomorphogenesis protein 1 (COP1) as a potential driver of metastasis. These findings illustrate the utility of the combined patient-derived CTC model and provide a glimpse of the promise of CTCs in identifying drivers of cancer metastasis.

Radiomics in Lung Metastases: A Systematic Review

Due to the rich vascularization and lymphatic drainage of the pulmonary tissue, lung metastases (LM) are not uncommon in patients with cancer. Radiomics is an active research field aimed at the extraction of quantitative data from diagnostic images, which can serve as useful imaging biomarkers for a more effective, personalized patient care. Our purpose is to illustrate the current applications, strengths and weaknesses of radiomics for lesion characterization, treatment planning and prognostic assessment in patients with LM, based on a systematic review of the literature.

Role of exosomes in non-small cell lung cancer and EGFR-mutated lung cancer

As an important mediator of information transfer between cells, exosomes play a unique role in regulating tumor growth, supporting vascular proliferation, tumor invasion, and metastasis. Exosomes are widely present in various body fluids, and therefore they can be used as a potential tool for non-invasive liquid biopsy. The present study reviews the role of exosomes in liquid biopsy, tumor microenvironment formation, and epithelial-mesenchymal transition in non-small cell lung cancer (NSCLC). By targeting epidermal growth factor receptor (EGFR) therapy as a first-line treatment for patients with NSCLC, this study also briefly describes the occurrence of EGRF+ exosomes and the role of exosomes and their contents in non-invasive detection and potential therapeutic targets in EGFR-mutated lung cancer.

Pleural metastasis of pulmonary adenocarcinoma mimicking diffuse mesothelioma: A case report and literature study

Conditions on pleura cover a broad range of pathology ranging from benign to malignant, which may potentially carry a poor prognosis and lead to high morbidity and mortality. Radiology plays a pivotal role in the diagnosis of pleural malignancy; however, the diagnostic endeavor can be challenging because of overlapping radiological appearances of one condition to another. This case report presents a 61-year-old male with worsening chronic shortness of breath. Despite early imaging resulting in highly suggested mesothelioma, subsequent biopsy proved the malignancy to be pulmonary adenocarcinoma. The patient underwent Pemetrexed-Cisplatin protocol in accordance with the biopsy result, and follow-up imaging depicted a marked improvement of the pleural condition. This case is a prime example of the challenge radiologists have to face regarding pleural tumors and dictates the necessity of a specialized multidisciplinary team to improve the patient's outcome.

Exosomes from EGFR-Mutated Adenocarcinoma Induce a Hybrid EMT and MMP9-Dependant Tumor Invasion

Exosomes, a class of extra cellular nano-sized vesicles (EVs), and their contents have gained attention as potential sources of information on tumor detection and regulatory drivers of tumor progression and metastasis. The effect of exosomes isolated from patients with an Epidermal Growth Factor Receptor (EGFR)-mutated adenocarcinoma on the promotion of epithelial–mesenchymal transition (EMT) and invasion were examined. Exosomes derived from serum of patients with EGFR-mutated non-small cell lung cancer (NSCLC) mediate the activation of the Phosphoinositide 3-kinase (PI3K)/AKT/ mammalian target of rapamycin (mTOR) pathway and induce an invasion through the up-regulation of matrix metalloproteinase-9 (MMP-9) in A549 cells. We observed a significant increase in the expression of vimentin, a mesenchymal marker, while retaining the epithelial characteristics, as evidenced by the unaltered levels of E-cadherin and Epithelial cell adhesion molecule (EPCAM). We also observed an increase of nuclear factor erythroid 2-related factor 2 (NFR2) and P-cadherin expression, markers of hybrid EMT. Exosomes derived from EGFR-mutated adenocarcinoma serum could be a potential mediator of hybrid EMT and tumor invasion. Understanding how cancerous cells communicate and interact with their environment via exosomes will improve our understanding of lung cancer progression and metastasis formation.

Lung Cancer in Women

BACKGROUND

Lung cancer is the leading cause of cancer-related death for women in the United States. Clinical characteristics, histology, epidemiology, and treatment responses are unique for women with lung cancer.

METHODS

Literature search of MEDLINE publications from 1989 to 2021 was conducted for lung cancer in women. Subsequent narrative review focused on identified differences in risk factors, diagnosis, and treatment of importance to the surgical care of these patients.

RESULTS

Studies investigating lung cancer, in which sex-differences are explored, demonstrated differences in risk factors, histology, and treatment response among women, with a significant post-surgical survival advantage over men (41.8 months vs 26.8 months, p=0.007) and greater clinical benefit from anti-PD1 combined with chemotherapy (HR=0.44, 95% CI: 0.25-0.76) compared with men (HR=0.76, 95% CI: 0.64-0.91). Smoking remains a dominant risk factor and multiple clinical trials suggest lung cancer screening provides greater benefit for women. However, young non-smoking patients with lung cancer are 2-fold more likely to be female, advocating for broader sex-based screening criteria. Potential roles of genetic mutations, estrogen signaling, and infectious elements in sex-based differences in presentation, histology, prognosis and treatment response are explored.

CONCLUSIONS

Overall, much remains unknown regarding how sex influences lung cancer risk, treatment decisions and outcomes. However, evidence of specific differences in presentation, environmental risk, molecular drivers, and mutational burden support the need to better leverage these sex-associated differences to further improve detection, diagnosis, surgical outcomes and systemic regimens in order to advance the overall care strategy for women with lung cancer.

Clinical and Imaging Features of Non-Small Cell Lung Cancer with G12C KRAS Mutation

Simple Summary

KRAS G12C mutations are important oncogenic mutations in lung cancer that can now be targeted by allosteric small molecule inhibitors. We assessed the imaging features and patterns of metastases in these lung cancers compared to other mutated lung cancers. We found that KRAS G12C NSCLC has distinct primary tumor imaging features and patterns of metastasis when compared to those of NSCLC driven by other genetic alterations. These distinct imaging features may offer clues to its presence and potentially guide management in the future.

Abstract

KRAS G12C mutations are important oncogenic mutations that confer sensitivity to direct G12C inhibitors. We retrospectively identified patients with KRAS+ NSCLC from 2015 to 2019 and assessed the imaging features of the primary tumor and the distribution of metastases of G12C NSCLC compared to those of non-G12C KRAS NSCLC and NSCLC driven by oncogenic fusion events (RET, ALK, ROS1) and EGFR mutations at the time of initial diagnosis. Two hundred fifteen patients with KRAS+ NSCLC (G12C: 83; non-G12C: 132) were included. On single variate analysis, the G12C group was more likely than the non-G12C KRAS group to have cavitation (13% vs. 5%, p = 0.04) and lung metastasis (38% vs. 21%; p = 0.043). Compared to the fusion rearrangement group, the G12C group had a lower frequency of pleural metastasis (21% vs. 41%, p = 0.01) and lymphangitic carcinomatosis (4% vs. 39%, p = 0.0001) and a higher frequency of brain metastasis (42% vs. 22%, p = 0.005). Compared to the EGFR+ group, the G12C group had a lower frequency of lung metastasis (38% vs. 67%, p = 0.0008) and a higher frequency of distant nodal metastasis (10% vs. 2%, p = 0.02). KRAS G12C NSCLC may have distinct primary tumor imaging features and patterns of metastasis when compared to those of NSCLC driven by other genetic alterations.

Management and Outcomes of Suspected Infectious and Inflammatory Lung Abnormalities Identified on Lung Cancer Screening CT

Background: Incidental findings are frequently encountered during lung cancer screening (LCS). Limited data describe the prevalence of suspected acute infectious and inflammatory lung processes on LCS and how they should be managed. Objective: To determine the prevalence, radiologic reporting and management, and outcome of suspected infectious and inflammatory lung processes identified incidentally during LCS, and to propose a management algorithm. Methods: This retrospective study included 6314 low dose CT (LDCT) examinations performed between June 2014 and April 2019 in 3800 patients as part of an established LCS program. Radiology reports were reviewed, and patients with potentially infectious or inflammatory lung abnormalities were identified and analyzed for descriptors of imaging findings, Lung-RADS designation, recommendations, and clinical outcomes. Based on the descriptors, outcomes and a >2% threshold risk of malignancy, a follow-up algorithm was developed to decrease additional imaging without affecting cancer detection. Results: A total of 331/3800 (8.7%) patients (178 men, 153 women; mean age: 66 ± 7 years) undergoing LCS had lung findings that were attributed to infection or inflammation. These abnormalities were reported as potentially significant findings using the "S" modifier in 149/331 (45.0%) and as the "dominant nodule" determining the Lung-RADS category in 96/331 (29.0%). Abnormalities were multiple or multifocal in 260/331 (78.5%). Common descriptors were ground-glass (155/331; 46.8%), tree-in-bud (56/331; 16.9%), consolidation (41/331; 12.4%), and clustered (67/331; 20.2%) opacities. A follow-up chest CT outside of screening was performed within 12 months or less in 264/331 (79.8%) and within 6 months or less in 286/331 (56.2%). A total of 260/331 (78.5%) opacities resolved on follow-up imaging. Two malignancies (2/331; 0.60%) were associated with these abnormalities, and both had consolidations. Theoretical adoption of a proposed management algorithm for suspected infectious and inflammatory findings reduced unnecessary follow-up imaging by 82.6% without missing a single malignancy. Conclusions: Presumed acute infectious or inflammatory lung abnormalities are frequently encountered in the setting of LCS. These opacities are commonly multifocal and resolve on follow-up. Less than 1% are associated with malignancy. Clinical impact: Adoption of a conservative management algorithm can standardize recommendations and reduce unnecessary imaging without increasing the risk of missing a malignancy.

Clinicopathologic and Longitudinal Imaging Features of Lung Cancer Associated With Cystic Airspaces: A Systematic Review and Meta-Analysis

BACKGROUND. Lung cancer (LC) associated with cystic airspaces is an uncommon presentation that is underrecognized on imaging. Additionally, understanding of its underlying pathology and risk factors is limited, which can contribute to delays in diagnosis. OBJECTIVE. The purpose of this analysis was to systematically review, analyze, and synthesize the medical literature to determine the imaging features of LC associated with cystic airspaces. EVIDENCE ACQUISITION. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included published research reporting the clinical, pathologic, and imaging features of LC associated with cystic airspaces. We then performed a pooled analysis of continuous and categoric data with respect to patient clinical characteristics, tumor pathologic features, underlying driver mutation, CT features, and evolution of these features over time. EVIDENCE SYNTHESIS. The analysis included eight original observational studies with a combined total of 341 patients with LC associated with cystic airspaces (weighted mean age, 61.8 years; range, 30-87 years; 135 women and 206 men). Most patients were current or previous smokers (127/192 [66.1%]). The most common histologic finding was adenocarcinoma (289/328 [88.1%]) followed by squamous cell carcinoma (30/328 [9.1%]). The most common driver mutations were EGFR (46/122 [37.7%]) and KRAS (21/122 [17.2%]). The cysts in LC associated with cystic airspaces commonly had nonuniform (104/114 [91.2%]) and thick (83/222 [37.4%]) walls, irregular margins (53/142 [37.3%]), and were unilocular (173/272 [63.6%]). Most cysts had a nodular component (210/328 [64.0%]). Over time, most cysts showed development or enlargement of the nodular component (61/89 [68.5%]), approximately half showed wall thickening (43/89 [48.3%]), and a minority evolved into completely solid lesions (11/89 [12.4%]). The size of the cystic component increased in 36 of 89 patients (40.4%), decreased in 28 (31.5%), and remained stable in 24 (27.0%). CONCLUSION. LC associated with cystic airspaces occurs most commonly as adeno-carcinoma and is seen in both smokers and nonsmokers. The cysts associated with LC show wall thickening and mural nodularity, which may evolve over time. LC associated with cystic airspaces can be indolent, and long-term surveillance with imaging should be considered if cysts are not resected. CLINICAL IMPACT. Familiarity with the imaging features and temporal evolution of LC associated with cystic airspaces can minimize delays in LC diagnosis. Future management guidelines should include protocols for follow-up and management of cystic lung lesions identified during diagnostic and LC screening CT.

Clinical and Imaging Features of Non-Small-Cell Lung Cancer in Young Patients

BACKGROUND

Non-small-cell lung cancer (NSCLC) in young adult patients is rare, with scarce data available in patients aged < 40 years and even less in those aged < 35 years. Our goal was to determine the presenting symptoms, clinicopathologic characteristics, and imaging features of young patients with NSCLC at time of diagnosis and compare them to those of older adults.

PATIENTS AND METHODS

We retrospectively analyzed the medical records and imaging of young patients (≤ 40 years old) with NSCLC treated at our institution between 1998 and 2018. Patients < 35 years old were compared to those between 35 and 40 years old. Characteristics of patients ≤ 40 years old were compared to older patients (> 40 years) from publicly available data sets.

RESULTS

We identified 166 young patients with NSCLC (median age, 36.6 years; range, 18-40 years). Most presented with nonspecific respiratory symptoms and were diagnosed with pneumonia (84/136, 62%). Compared to patients < 35 years old, patients 35-40 years old were more likely to have malignancy detected incidentally (15% vs. 5%, P = .04). Patients < 35 years old were more likely to have central tumors (55% vs. 33%, P = .02) and to have bone (38% vs. 19%, P = .007) and lung (39% vs. 24%, P = .03) metastases. Compared to older patients (> 40 years), young patients were more likely to be never smokers (65.0% vs. 14.7%, P < .001) and to have advanced disease (88% vs. 66%, P < .001).

CONCLUSION

Young patients with NSCLC often present with nonspecific symptoms and have advanced disease at diagnosis, often mimicking other pathologies. Awareness of the clinical presentation and imaging features of NSCLC in young patients may help minimize delays in diagnoses.

Role of imaging biomarkers in mutation-driven non-small cell lung cancer

Lung cancer remains the leading cause of cancer-related deaths worldwide. The treatment of non-small cell lung cancer (NSCLC), which accounts for a vast majority of lung cancers, has shifted to personalized, targeted therapy following discoveries of several targetable oncogenic mutations. Targeting of specific mutations has improved outcomes in many patients. This success has led to several target-specific agents replacing chemotherapy as first-line treatment in certain mutated NSCLC. Several researchers have reported that there may be imaging biomarkers that may be predictive of the presence of these mutations. These features, when present, have the potential in triaging patients into the most appropriate diagnostic and treatment algorithms. Distinct imaging features and patterns of metastases that have been associated with NSCLC with various targetable oncogenic mutations are presented in this review.

Imaging Features and Patterns of Metastasis in Non-Small Cell Lung Cancer with RET Rearrangements

Rearranged during transfection proto-oncogene (RET) fusions represent a potentially targetable oncogenic driver in non-small cell lung cancer (NSCLC). Imaging features and metastatic patterns of advanced RET fusion-positive (RET+) NSCLC are not well established. Our goal was to compare the imaging features and patterns of metastases in RET+, ALK+ and ROS1+ NSCLC. Patients with RET+, ALK+, or ROS1+ NSCLC seen at our institution between January 2014 and December 2018 with available pre-treatment imaging were identified. The clinicopathologic features, imaging characteristics, and the distribution of metastases were reviewed and compared. We identified 215 patients with NSCLC harboring RET, ALK, or ROS1 gene fusion (RET = 32; ALK = 116; ROS1 = 67). Patients with RET+ NSCLC were older at presentation compared to ALK+ and ROS1+ patients (median age: RET = 64 years; ALK = 51 years, p < 0.001; ROS = 54 years, p = 0.042) and had a higher frequency of neuroendocrine histology (RET = 12%; ALK = 2%, p = 0.025; ROS1 = 0%, p = 0.010). Primary tumors in RET+ patients were more likely to be peripheral (RET = 69%; ALK = 47%, p = 0.029; ROS1 = 36%, p = 0.003), whereas lobar location, size, and density were comparable across the three groups. RET+ NSCLC was associated with a higher frequency of brain metastases at diagnosis compared to ROS1+ NSCLC (RET = 32%, ROS1 = 10%; p = 0.039. Metastatic patterns were otherwise similar across the three molecular subgroups, with high incidences of lymphangitic carcinomatosis, pleural metastases, and sclerotic bone metastases. RET+ NSCLC shares several distinct radiologic features and metastatic spread with ALK+ and ROS1+ NSCLC. These features may suggest the presence of RET fusions and help identify patients who may benefit from further molecular genotyping.

Clinicopathologic and Imaging Features of Non-Small-Cell Lung Cancer with MET Exon 14 Skipping Mutations

MET exon 14 (METex14) skipping mutations are an emerging potentially targetable oncogenic driver mutation in non-small-cell lung cancer (NSCLC). The imaging features and patterns of metastasis of NSCLC with primary METex14 skipping mutations (METex14-mutated NSCLC) are not well described. Our goal was to determine the clinicopathologic and imaging features that may suggest the presence of METex14 skipping mutations in NSCLC. This IRB-approved retrospective study included NSCLC patients with primary METex14 skipping mutations and pre-treatment imaging data between January 2013 and December 2018. The clinicopathologic characteristics were extracted from electronic medical records. The imaging features of the primary tumor and metastases were analyzed by two thoracic radiologists. In total, 84 patients with METex14-mutated NSCLC (mean age = 71.4 ± 10 years; F = 52, 61.9%, M = 32, 38.1%; smokers = 47, 56.0%, nonsmokers = 37, 44.0%) were included in the study. Most tumors were adenocarcinoma (72; 85.7%) and presented as masses (53/84; 63.1%) that were peripheral in location (62/84; 73.8%). More than one in five cancers were multifocal (19/84; 22.6%). Most patients with metastatic disease had only extrathoracic metastases (23/34; 67.6%). Fewer patients had both extrathoracic and intrathoracic metastases (10/34; 29.4%), and one patient had only intrathoracic metastases (1/34, 2.9%). The most common metastatic sites were the bones (14/34; 41.2%), the brain (7/34; 20.6%), and the adrenal glands (7/34; 20.6%). Four of the 34 patients (11.8%) had metastases only at a single site. METex14-mutated NSCLC has distinct clinicopathologic and radiologic features.