Comparing interplay effects in scanned proton therapy of lung cancer: Free breathing with various layer and volume rescanning versus respiratory gating with different gate widths

PURPOSE

We investigated interplay effects and treatment time (TT) in scanned proton therapy for lung cancer patients. We compared free-breathing (FB) approaches with multiple rescanning strategies and respiratory-gating (RG) methods with various gating widths to identify the superior irradiation technique.

METHODS

Plans were created with 4/1, 2/2, and 1/4 layered/volume rescans of FB (L4V1, L2V2, and L1V4), and 50%, 30%, and 10% gating widths of the total respiratory curves (G50, G30, and G10) of the RG plans with L4V1. We calculated 4-dimensional dynamic doses assuming a constant sinusoidal curve for six irradiation methods. The reconstructed doses per fraction were compared with planned doses in terms of dose differences in 99% clinical-target-volume (CTV) (ΔD99%), near-maximum dose differences (ΔD2%) at organs-at-risk (OARs), and TT.

RESULTS

The mean/minimum CTV ΔD99% values for FB were -1.0%/-4.9%, -0.8%/-4.3%, and -0.1%/-1.0% for L4V1, L2V2, and L1V4, respectively. Those for RG were -0.3%/-1.7%, -0.1%/-1.0%, and 0.0%/-0.5% for G50, G30, and G10, respectively. The CTV ΔD99% of the RGs with less than 50% gate width and the FBs of L1V4 were within the desired tolerance (±3.0%), and the OARs ΔD2% for RG were lower than those for FB. The mean TTs were 90, 326, 824, 158, 203, and 422 s for L4V1, L2V2, L1V4, G50, G30, and G10, respectively.

CONCLUSIONS

FB (L4V1) is the most efficient treatment, but not necessarily the optimal choice due to interplay effects. To satisfy both TT extensions and interplay, RG with a gate width as large as possible within safety limits is desirable.

Challenges in diagnosis and biomarker testing for RET-altered lung and thyroid cancer care: an international mixed-method study

BACKGROUND

The introduction of new targeted therapies for RET-altered lung and thyroid cancers (LC/TC) has impacted pathologists' practice by making genomic testing more relevant. Variations in health systems and treatment access result in distinct clinical challenges and barriers. This study aimed to assess practice gaps and challenges experienced by pathologists involved in the diagnosis of RET-altered LC/TC, including biomarker testing, to inform educational solutions.

METHODS

Pathologists in Germany, Japan, the UK, and US participated in this ethics-approved mixed-methods study, which included interviews and surveys (data collected January-March 2020). Qualitative data was thematically analysed, quantitative data was analysed with chi-square and Kruskal-Wallis H-tests, and both were triangulated.

RESULTS

A total of 107 pathologists took part in this study. Knowledge gaps were reported regarding genomic testing for LC/TC in Japan (79/60%), the UK (73/66%), and the US (53/30%). Skill gaps were reported when selecting genomic biomarker tests to diagnose TC in Japan (79%), the UK (73%) and US (57%) and when performing specific biomarker tests, especially in Japan (82% for RET) and in the UK (75% for RET). Japanese participants (80%) reported uncertainty about what information to share with the multidisciplinary team to ensure optimal patient-centered care. At the time of data collection, pathologists in Japan faced access barriers to using RET biomarker tests: only 28% agreed that there are relevant RET genomic biomarker tests available in Japan, versus 67% to 90% in other countries.

CONCLUSIONS

This study identified areas where pathologists need additional continuing professional development opportunities to enhance their competencies and better support delivery of care to patients with RET-altered lung or thyroid tumours. Addressing identified gaps and improving competencies of pathologists in this field should be emphasised in continuing medical education curricula and through quality improvement initiatives. Strategies deployed on an institutional and health system level should aim to improve interprofessional communication and genetic biomarker testing expertise.

Comparisons on the intraoperative desaturation and postoperative outcomes in non-intubated video-assisted thoracic surgery with supraglottic airway devices or high-flow nasal oxygen: A retrospective study

BACKGROUND

Few studies have compared intraoperative oxygenation and perioperative outcomes between non-intubated video-assisted thoracic surgery (NIVATS) with supraglottic airway devices (SADs) and NIVATS with high flow nasal oxygenation (HFNO). The aim of this retrospective study was to compare the intraoperative desaturation rate and postoperative outcomes between NIVATS with SADs and NIVATS with HFNO.

METHODS

Data regarding NIVATS performed for lung cancer from January 2020 to December 2021 were collected. Intraoperative anesthetic results, post-anesthetic adverse effects, and surgical outcomes for patients who received SAD or HFNO were analyzed using propensity score-matched and unmatched analysis.

RESULTS

In total, 199 patients with i-gel™ and 95 patients with HFNO were included. Significantly more female patients (91.6 vs. 82.4%, p = 0.0378) and fewer wedge resections (78.9 vs. 85.4%, p = 0.0258) were observed in the HFNO group. Among 250 patients who underwent NIVATS wedge resections under total intravenous anesthesia, those who received HFNO had a significantly higher desaturation event rate (19.8% vs. 7.9% in i-gel™ group; p = 0.0063), lower nadir SPO₂ (94.0% vs. 96.1% in i-gel™ group; p = 0.0012), and longer hospitalization (4.0 ± 0.8 vs. 3.6 ± 0.6 in i-gel™ group; p < 0.0001). However, propensity score matching analysis revealed no significant between-group difference in the desaturation rate. A log-rank test revealed that smoking (p = 0.0005) and HFNO (p = 0.0074) were associated with intraoperative desaturation.

CONCLUSION

The rate of SAD use in NIVATS was twice the rate of HFNO use, especially for wedge resections. There is uncertain airway patency and limited flow through HFNO during one-lung ventilation, whereas SADs like i-gel™ presented a significantly less intraoperative desaturation rate over time and similar postoperative outcomes.

Applications of CRISPR/Cas technology against drug-resistant lung cancers: an update

Out of all the cancer types, the most prevalent one is lung cancer. Multiple genes and signaling pathways play role in the progression of lung cancer. Considering the wider prevalence and fatality of lung cancer it has become the focus of current cancer research. Though currently used approaches have shown positive results against lung cancer but success against non-small cell lung cancer (NSCLC) still looms as an enigma for the entire research fraternity. The development of resistance against inhibitors within a short span is one of the reasons responsible for the failure and relapse of lung cancer. Under these prevailing conditions genome/gene-editing technology using clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR associated proteins (Cas), popularly known as CRISPR/Cas technology offers a convenient and flexible method for inducing precise changes within the lung cancer cell. Additionally, CRISPR-barcoding and CRISPR knockout screens at the genome-wide level can help in the functional investigation of specific mutations and identification of novel cancer drivers respectively. Several variants of the CRISPR/Cas system are being developed to limit off-targeting with enhanced precision. The present review article updates the usefulness of CRISPR/Cas technology against various types of lung cancers.

Revisiting the formalism of equivalent uniform dose based on the linear-quadratic and universal survival curve models in high-dose stereotactic body radiotherapy

Purpose

To examine the equivalent uniform dose (EUD) formalism using the universal survival curve (USC) applicable to high-dose stereotactic body radiotherapy (SBRT).

Materials and methods

For nine non-small-cell carcinoma cell (NSCLC) lines, the linear-quadratic (LQ) and USC models were used to calculate the EUD of a set of hypothetical two-compartment tumor dose–volume histogram (DVH) models. The dose was varied by ±5%, ±10%, and ±20% about the prescription dose (60 Gy/3 fractions) to the first compartment, with fraction volume varying from 1% and 5% to 30%. Clinical DVHs of 21 SBRT treatments of NSCLC prescribed to the 70–83% isodose lines were also considered. The EUD of non-standard SBRT dose fractionation (EUD_SBRT) was further converted to standard fractionation of 2 Gy (EUD_CFRT) using the LQ and USC models to facilitate comparisons between different SBRT dose fractionations. Tumor control probability (TCP) was then estimated from the LQ- and USC-EUD_CFRT.

Results

For non-standard SBRT fractionation, the deviation of the USC- from the LQ-EUD_SBRT is largely limited to 5% in the presence of dose variation up to ±20% to fractional tumor volume up to 30% in all NSCLC cell lines. Linear regression with zero constant yielded USC-EUD_SBRT = 0.96 × LQ-EUD_SBRT (r² = 0.99) for the clinical DVHs. Converting EUD_SBRT into standard 2‑Gy fractions by the LQ formalism produced significantly larger EUD_CFRT than the USC formalism, particularly for low \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha /\beta$$\end{document}α/β ratios and large fraction dose. Simplified two-compartment DVH models illustrated that both the LQ- and USC-EUD_CFRT values were sensitive to cold spot below the prescription dose with little volume dependence. Their deviations were almost constant for up to 30% dose increase above the prescription. Linear regression with zero constant yielded USC-EUD_CFRT = 1.56 × LQ-EUD_CFRT (r² = 0.99) for the clinical DVHs. The clinical LQ-EUD_CFRT resulted in median TCP of almost 100% vs. 93.8% with USC-EUD_CFRT.

Conclusion

A uniform formalism of EUD should be defined among the SBRT community in order to apply it as a single metric for dose reporting and dose–response modeling in high-dose-gradient SBRT because its value depends on the underlying cell survival model and the model parameters. Further investigations of the optimal formalism to derive the EUD through clinical correlations are warranted.

Electronic supplementary material

The online version of this article (10.1007/s00066-020-01713-w) contains supplementary material, which is available to authorized users.

Clinical Validation of Discordant Trunk Driver Mutations in Paired Primary and Metastatic Lung Cancer Specimens

OBJECTIVES

To propose an operating procedure for validation of discordant trunk driver mutations.

METHODS

Concordance of trunk drivers was examined by next-generation sequencing in 15 patients with two to three metastatic lung cancers and 32 paired primary and metastatic lung cancers.

RESULTS

Tissue identity was confirmed by genotyping 17 single-nucleotide polymorphisms within the panel. All except three pairs showed concordant trunk drivers. Quality assessment conducted in three primary and metastatic pairs with discordant trunk drivers indicates metastasis from a synchronous or remote lung primary in two patients. Review of literature revealed high discordant rates of EGFR and KRAS mutations, especially when Sanger sequencing was applied to examine primary and lymph node metastatic tumors.

CONCLUSIONS

Trunk driver mutations are highly concordant in primary and metastatic tumors. Discordance of trunk drivers, once confirmed, may suggest a second primary cancer. Guidelines are recommended to establish standard operating procedures for validation of discordant trunk drivers.

The NF1 somatic mutational landscape in sporadic human cancers

Background

Neurofibromatosis type 1 (NF1: Online Mendelian Inheritance in Man (OMIM) #162200) is an autosomal dominantly inherited tumour predisposition syndrome. Heritable constitutional mutations in the NF1 gene result in dysregulation of the RAS/MAPK pathway and are causative of NF1. The major known function of the NF1 gene product neurofibromin is to downregulate RAS. NF1 exhibits variable clinical expression and is characterized by benign cutaneous lesions including neurofibromas and café-au-lait macules, as well as a predisposition to various types of malignancy, such as breast cancer and leukaemia. However, acquired somatic mutations in NF1 are also found in a wide variety of malignant neoplasms that are not associated with NF1.

Main body

Capitalizing upon the availability of next-generation sequencing data from cancer genomes and exomes, we review current knowledge of somatic NF1 mutations in a wide variety of tumours occurring at a number of different sites: breast, colorectum, urothelium, lung, ovary, skin, brain and neuroendocrine tissues, as well as leukaemias, in an attempt to understand their broader role and significance, and with a view ultimately to exploiting this in a diagnostic and therapeutic context.

Conclusion

As neurofibromin activity is a key to regulating the RAS/MAPK pathway, NF1 mutations are important in the acquisition of drug resistance, to BRAF, EGFR inhibitors, tamoxifen and retinoic acid in melanoma, lung and breast cancers and neuroblastoma. Other curiosities are observed, such as a high rate of somatic NF1 mutation in cutaneous melanoma, lung cancer, ovarian carcinoma and glioblastoma which are not usually associated with neurofibromatosis type 1. Somatic NF1 mutations may be critical drivers in multiple cancers. The mutational landscape of somatic NF1 mutations should provide novel insights into our understanding of the pathophysiology of cancer. The identification of high frequency of somatic NF1 mutations in sporadic tumours indicates that neurofibromin is likely to play a critical role in development, far beyond that evident in the tumour predisposition syndrome NF1.

Antitumor activity of paederosidic acid in human non-small cell lung cancer cells via inducing mitochondria-mediated apoptosis

This study was aimed to investigate antitumor activity of paederosidic acid (PA) in human non-small cell lung cancer cells and explore the related mechanisms. The anti-proliferative effects of PA on A549 cells were evaluated by MTT method and the IC₅₀ values were calculated. Furthermore, the PA-induced apoptosis in A549 cells was determined by fluorescence microscope via staining with DAPI and by flow cytometer via staining with FITC conjugated Annexin V/PI. The expression of apoptosis-related or signaling proteins was investigated by Western blotting. Our results demonstrated that PA showed significant anti-tumor activity on lung cancer in vitro; the mechanisms were involved in inducing mitochondria-mediated apoptosis via up-regulation of caspase-3, caspase-8, caspase-9, Bid, Bax, down-regulation of Bcl-2 and stimulating the release of Cyto-C from mitochondria. In addition, JNK phosphorylation levels significantly increased concomitantly with decrease in Akt phosphorylation after treatment with PA in A549 cells. However, JNK siRNA-transfected cells diminished PA-induced caspase-3, 8 and 9, Bid and Bax activaton while enhanced the Bcl-2 activation. Collectively, these results indicated that PA-induced JNK activation played an important functional role in apoptosis.

Prediction of clinical outcome after stereotactic body radiotherapy for non-small cell lung cancer using diffusion-weighted MRI and (18)F-FDG PET

PURPOSE/OBJECTIVES

To evaluate the use of diffusion-weighted magnetic resonance imaging (DW-MRI) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for predicting disease progression (DP) among patients with non-small cell lung carcinoma (NSCLC) treated with stereotactic body radiotherapy (SBRT).

MATERIALS/METHODS

Fifteen patients with histologically confirmed stage I NSCLC who underwent pre-treatment DW-MRI and PET and were treated with SBRT were enrolled. The mean apparent diffusion coefficient (ADC) value and maximum standardised uptake value (SUVmax) were measured at the target lesion and evaluated for correlations with DP.

RESULTS

The median pre-treatment ADC value was 1.04×10(-3) (range 0.83-1.29×10(-3))mm(2)/s, and the median pre-treatment SUVmax was 9.9 (range 1.6-30). There was no correlation between the ADC value and SUVmax. The group with the lower ADC value (≤1.05×10(-3)mm(2)/s) and that with a higher SUVmax (≥7.9) tended to have poor DP, but neither trend was statistically significant (p=0.09 and 0.32, respectively). The combination of the ADC value and SUVmax was a statistically significant predictor of DP (p=0.036).

CONCLUSION

A low ADC value on pre-treatment DW-MRI and a high SUVmax may be associated with poor DP in NSCLC patients treated with SBRT. Using both values in combination was a better predictor.