Role of imaging in diagnosis, staging and follow-up of lung cancer

Development and validation of nomograms based on clinical characteristics and CT reports for the preoperative prediction of precise lymph node dissection in lung cancer

OBJECTIVE

To develop and validate nomograms for preoperative prediction of precision lymph node (LN) dissection in lung cancer.

PATIENTS AND METHODS

The prediction models of each group LNs (LNx) were developed in a primary cohort that consisted of 1380 patients with clinicopathologically confirmed lung cancer. Clinical characteristics and CT reports were extracted. Patients with LNx dissection were divided into training cohort and testing cohort. Nomograms were built through univariate and multivariate regression analysis in the training cohort and internally verified in the testing cohort. The accuracy of the models was verified by constructing survival analysis in patients without LNx dissection.

RESULTS

Due to the lack of sufficient patients for LN1, 8, 13, a total of 10 nomograms were constructed in this study, including LN-2 ∼ 7, 9 ∼ 12. According to the nomogram of each group LN, the most common independent risk factors predicting LN status were CT-reported lymphadenectasis, tumor diameter and location, and the others include age, gender, and whether there were multiple nodules, etc. All models showed good discrimination, with the average C-index of 0.738 in the training cohort and 0.707 in the testing cohort. Survival analysis in patients without LNx dissection all showed the high accuracy of each nomogram to predict LN metastasis status and TNM staging.

CONCLUSION

We constructed nomograms to predict the metastasis status of each group of lymph nodes based on clinical characteristics and CT reports. Surgeons can accurately determine the extent of lymph node dissection in patients with lung cancer based on our nomogram models before surgery.

High level of FHL2 exacerbates the outcome of non-small cell lung cancer (NSCLC) patients and the malignant phenotype in NSCLC cells

Non-small cell lung cancer (NSCLC) is a malignant tumour with high mortality. FHL2 has been identified as a biomarker of lung cancer. This research explored the effects of FHL2 expression on NSCLC. NSCLC-associated data sets were collected from the assistant for clinical bioinformatics and TCGA databases respectively. The association between FHL2 and clinical characteristics, the prognostic significance of FHL2 and the influences of various variables on NSCLC were determined by Pearson's chi-squared test, the Kaplan-Meier curve and the Cox regression model respectively. FHL2 level was altered by cell transfection and was measured by qRT-PCR. Tumour xenograft formation was completed by inoculating sh-FHL2/pcDNA-FHL2 transfected cells into BALB/c nude mice. Protein expression was assessed by western blot. Cell apoptosis, proliferation and epithelial - mesenchymal transition (EMT) characteristics were evaluated employing TUNEL, BrdU⁺ and microscopic observation respectively. The expression of Ki67 and N-cadherin was assessed by immunohistochemistry. The results showed that FHL2 was highly expressed in NSCLC tissues. Patients with high FHL2 expression experienced lower overall survival probability. FHL2 knockdown promoted apoptosis, but inhibited EMT of A549 and NCI-H460 cells, which was verified by the increased ratios of cleaved caspase 9/caspase 9 and cleaved caspase 3/caspase 3, as well as augmented E-cadherin and reduced N-cadherin. In an in vivo assay FHL2 knockdown decreased tumour volume and weight, repressed EMT, but enhanced apoptosis. FHL2 upregulation showed the opposite effects of FHL2 knockdown. Furthermore, FHL2 upregulation facilitated cell proliferation both in in vitro and in vivo assays. These outcomes indicated that high level of FHL2 facilitated tumorigenesis, as well as the proliferation and EMT of NSCLC cells.

A clinicopathologic analysis of microscopic extension in small cell lung cancer and lung adenocarcinoma: Determination of clinical target volume with precise radiotherapy

PURPOSE

The identification of the clinical target volume (CTV) is particularly important in the precise radiotherapy of lung cancer. The purpose of this study was to determine the extension margin from gross tumor volume (GTV) to CTV in primary small cell lung cancer (SCLC) and lung adenocarcinoma (ADC) by microscopic extension (ME).

MATERIAL AND METHODS

The data of 25 cases of SCLC and 29 cases of ADC from August 2015 to August 2020 were analyzed. The measurement of tumor size between preoperative thoracic computed tomography (CT) and postoperative macroscopic specimens was compared, and the ME range of tumor cells was measured under a microscope to determine its correlation with clinical features and pathological manifestations.

RESULTS

A total of 217 slides were examined, corresponding to 103 slides for SCLC and 114 slides for ADC. The radiologic sizes of the tumors in SCLC and ADC were 12.8 and 7.9 mm, respectively (p = 0.09), and the macroscopic sizes were 12.5 and 8.5 mm, respectively (p = 0.07). There was a significant correlation between the radiologic and macroscopic size of the same tumor sample (r = 0.886). Compared with ADC, more SCLC tumor cells infiltrated through vascular or lymphatic dissemination (16% vs. 9%, p = 0.047). The mean ME value was 2.81 mm for SCLC and 2.02 mm for ADC (p = 0.012). To take into account 95% of the ME, a margin of 8 and 7.7 mm must be expanded for SCLC and ADC, respectively. The ME value of the tumor was related to the presence of atelectasis, the location of the tumor, and the Ki-67 cell proliferation index.

CONCLUSION

The GTV of the tumor was contoured according to CT images, which was basically consistent with the actual tumor size. The GTVs of SCLC and ADC should be expanded by 8 and 7.7 mm, respectively, to fully cover the subclinical lesions in 95% of cases.

To Biopsy or Not to Biopsy?: A Matched Cohort Analysis of Early-Stage Lung Cancer Treated with Stereotactic Radiation with or Without Histologic Confirmation

PURPOSE

For nonoperable stage I non-small cell lung cancer, stereotactic body radiation therapy (SBRT) has emerged as a standard treatment option. We aimed to compare the clinical outcomes of lung SBRT between patients with versus without pathologic cancer diagnosis.

METHODS AND MATERIALS

We included patients treated by SBRT for a single pulmonary lesion between July 2009 and July 2017. Patients in the clinical diagnosis group had a positron emission tomography/computed tomography scan showing hypermetabolism, growth of the mass on sequential computed tomography, and were not eligible for biopsy, refused biopsy, or had an inconclusive biopsy. For each of those patients, a matched pair in the pathologic diagnosis group was identified by matching for patient, treatment, and tumoral characteristics. We performed a power calculation to estimate the sample size required to detect a difference arising from a 5% or 15% rate of benign processes in the group without pathology.

RESULTS

A total of 924 lung SBRT treatments were performed among 878 patients from 2009 to 2017. Within this population, 131 patients were treated based on clinical findings. They were matched with 131 patients with a pathologic diagnosis who received treatment. At 3 years, no significant differences were observed in overall survival (hazard ratio [HR], 1.2; 95% confidence interval [CI], 0.7-2.1), local control (HR, 0.9; 95% CI, 0.4-2), or regional (HR, 0.5; 95% CI, 0.2-1.4) or distant recurrence (HR, 0.6; 95% CI, 0.3-1.1).

CONCLUSIONS

In our population, we found no clinically significant difference in patterns of recurrence or survival after lung SBRT for patients who had received clinical versus pathological diagnoses. There was, however, a trend toward more distant recurrences in the pathologic diagnosis group. Our power calculation suggests that data from multiple institutions would be required to rule out a difference in outcomes due to 5% to 15% of clinically diagnosed cases being treated for benign processes.

TRIM59 promotes gefitinib resistance in EGFR mutant lung adenocarcinoma cells

AIMS

The relationship between TRIM59 and drug resistance is elusive despite of its multiple uncovered roles in human cancers. Here we aimed to characterize the expression status of TRIM59 in gefitinib-resistant EGFR mutant lung adenocarcinoma cells and elucidate its mechanism underlying the drug resistance.

MAIN METHODS

Gefitinib-resistant cell lines were established by progressive dosage. Relative expression of TRIM59 was determined by both real-time PCR and Western blot. Target gene knockdown was achieved by specific shRNAs. Cell viability was measured by MTT assay. Cell apoptosis was analyzed by flow cytometry with Annexin V/7-AAD double staining. Cell proliferation was determined by clonogenic formation assay. Migration and invasion capacities were detected using transwell chamber assay. Direct interaction between TRIM59 and STAT3 was analyzed by co-immunoprecipitation assay.

KEY FINDINGS

We first observed overexpression of TRIM59 in gefitinib-resistant EGFR mutant lung adenocarcinoma cells. ShRNA-mediated knockdown of TRIM59 significantly inhibited cell viability and stimulated apoptosis. Meanwhile, TRIM59-deficiency suppressed cell migration and invasion. We further identified the interaction between TRIM59 and STAT3. TRIM59-deficiency remarkably impaired the activation of STAT3 signaling. STAT3-specific shRNAs significantly re-sensitized TRIM59-proficient EGFR mutant lung adenocarcinoma cells to gefitinib.

SIGNIFICANCE

Our data characterized aberrant TRIM59 overexpression in gefitinib-resistance EGFR mutant lung adenocarcinoma cells, and indicated the potential involvement of TRIM59-STAT3 signaling in the occurrence of gefitinib-resistance.

Improved image quality of low-dose CT combining with iterative model reconstruction algorithm for response assessment in patients after treatment of malignant tumor

Background

To evaluate the image quality and radiation dose of low-dose (LD) computed tomography (LD-CT) combining with iterative model reconstruction (IMR) algorithm for response assessment in patients after treatment of malignant tumor compared with routine-dose CT (RD-CT).

Methods

Forty-seven patients [mean age 57.8±10.9 years, 30 males, body mass index (BMI) 22.09±2.35 kg/m²] after treatment of malignant tumor underwent contrast-enhanced chest and abdomen CT twice for response assessment with an interval of 6 months according to clinical routine. The first CT scans were performed with RD protocol at 120 kVp and images were reconstructed with filtered back projection (FBP) algorithm; while the second scans were performed with LD protocol at 100 kVp and images were reconstructed with FBP and IMR algorithm respectively. All scans were performed using an automatic tube current modulation technique with 150 mAs as reference. Objective image quality including CT attenuation, image noise, and contrast to noise ratio (CNR), and subjective image quality including artifacts, noise, visualization of small structures and confidence of targeted lesions, as well as lesion detection were assessed and compared.

Results

Effective radiation dose of LD-CT scans was reduced 54.8% compared to RD-CT scans (26.89±3.35 vs. 12.14±2.09 mSv). Higher CT attenuation was found in both LD-IMR and LD-FBP images compared to RD-FBP images. Better subjective image quality and CNR as well as lower objective noise were found in LD-IMR images (all, P<0.05). Two small lesions with the diameter less than 1 cm were missed in LD-FBP images, which were able to be observed in LD-IMR images.

Conclusions

IMR is able to help more than half of reduction of radiation dose without compromising the quality of diagnostic information in patients after treatment of malignant tumors to chest and abdomen CT for response assessment.

A quantitative immunoassay for lung cancer biomarker CIZ1b in patient plasma

OBJECTIVES

Non-invasive tests for early detection of lung cancer are an important unmet clinical need. CIZ1b plasma biomarker can discriminate stage 1 lung cancer from within high-risk groups with clinically useful accuracy, with ROC AUCs in excess of 0.9 for two independent retrospective cohorts, and could therefore meet this need. Our aim was to characterise the native state of the biomarker and develop a quantitative immunoassay.

DESIGN AND METHODS

Selective denaturation, preparative electrophoresis and mass spectrometry of human plasma were used to characterise the biomarker and interaction partners. A sandwich ELISA was generated, and specificity for CIZ1b biomarker tested on lung cancer patient plasma.

RESULTS

CIZ1b biomarker is a denaturation-resistant complex between a C-terminal fragment of CIZ1 bearing the CIZ1b epitope specified by alternative splicing of exon14, and fibrinogen alpha chain. Reconstitution of the biomarker epitope with purified fibrinogen and CIZ1b, but not CIZ1a (non-alternatively spliced exon 14) confirmed the specificity of the results. The endogenous complex is highly stable in lung cancer plasma and can be quantified by pairing of a CIZ1b exon-junction specific antibody with detection of fibrinogen. Application of this sandwich ELISA to a prospectively collected development set of plasmas reveals the same level of accuracy as the western blot used to validate the discriminatory capability of the biomarker.

CONCLUSIONS

Unexpected and unusual molecular structure of CIZ1b in native plasma has complicated immunoassay design, and delayed translation of this promising biomarker. However, CIZ1b can now be measured using a high-throughput, hospital-friendly sandwich ELISA format, overcoming an important barrier to further clinical development and application of this blood test for early stage lung cancer.

Dual-Energy Computed Tomography Virtual Monoenergetic Imaging of Lung Cancer: Assessment of Optimal Energy Levels

OBJECTIVE

The aim of the study was to evaluate objective and subjective image qualities of virtual monoenergetic imaging (VMI) in dual-source dual-energy computed tomography (DECT) and optimal kiloelectron-volt (keV) levels for lung cancer.

METHODS

Fifty-nine lung cancer patients underwent chest DECT. Images were reconstructed as VMI series at energy levels of 40, 60, 80, and 100 keV and standard linear blending (M_0.3) for comparison. Objective and subjective image qualities were assessed.

RESULTS

Lesion contrast peaked in 40-keV VMI reconstructions (2.5 ± 2.9) and 60 keV (1.9 ± 3.0), which was superior to M_0.3 (0.5 ± 2.7) for both comparisons (P < 0.001). Compared with M_0.3, subjective ratings were highest for 60-keV VMI series regarding general image quality (4.48 vs 4.52; P = 0.74) and increased for lesion demarcation (4.07 vs 4.84; P < 0.001), superior to all other VMI series (P < 0.001). Image sharpness was similar between both series. Image noise was rated superior in the 80-keV and M_0.3 series, followed by 60 keV.

CONCLUSIONS

Virtual monoenergetic imaging reconstructions at 60-keV provided the best combination of subjective and objective image qualities in DECT of lung cancer.