Minimal-dose computed tomography is superior to chest x-ray for the follow-up and treatment of patients with resected lung cancer

The Overlooked Cornerstone in Precise Medicine: Personalized Postoperative Surveillance Plan for NSCLC

Non-small cell lung cancer recurrence after curative-intent surgery remains a challenge despite advancements in treatment. We review postoperative surveillance strategies and their impact on overall survival, highlighting recommendations from clinical guidelines and controversies. Studies suggest no clear benefit from more intensive imaging, whereas computed tomography scans reveal promise in detecting recurrence. For early-stage disease, including ground-glass opacities and adenocarcinoma in situ or minimally invasive adenocarcinoma, less frequent surveillance may suffice owing to favorable prognosis. Liquid biopsy, especially circulating tumor deoxyribonucleic acid, holds potential for detecting minimal residual disease. Clinicopathologic factors and genomic profiles can also provide information about site-specific metastases. Machine learning may enable personalized surveillance plans on the basis of multi-omics data. Although precision medicine transforms non-small cell lung cancer treatment, optimizing surveillance strategies remains essential. Tailored surveillance strategies and emerging technologies may enhance early detection and improve patients' survival, necessitating further research for evidence-based protocols.

Is it necessary to define new diagnostic reference levels during pandemics like the Covid19-?

Introduction

This study intended to assess the dose length product (DLP), effective cumulative radiation dose (E.D.), and additional cancer risk (ACR) due to a chest CT scan to detect or follow up the Covid-19 disease in four university-affiliated hospitals that used different imaging protocols. Indeed, this study aimed to examine the differences in decision-making between different imaging centers in choosing chest CT imaging protocols during the pandemic, and to assess whether a new diagnostic reference level (DRL) is needed in pandemic situations.

Methods

This retrospective study assessed the E.D. of all chest imagings for Covid-19 for six months in four different hospitals in our country. Imaging parameters and DLP (mGy.cm) were recorded. The E.D.s and ACRs from chest CT scans were calculated using an online calculator.

Results

Thousand-six hundred patients were included in the study. The mean cumulative dose due to chest CT was 3.97 mSv which might cause 2.59 × 10^-2 ACR. The mean cumulative E.D. in different hospitals was in the range of 1.96-9.51 mSv.

Conclusions

The variety of mean E.D.s shows that different hospitals used different imaging protocols. Since there is no defined DRL in the pandemic, some centers use routine protocols, and others try to reduce the dose but insufficiently.In pandemics such as Covid-19, when CT scan is used for screening or follow-up, DLPs can be significantly lower than in normal situations. Therefore, international regularized organizations such as the international atomic energy agency (IAEA) or the international commission on radiological protection (IRCP) should provide new DRL ranges.

Performance of a rule-based semi-automated method to optimize chart abstraction for surveillance imaging among patients treated for non-small cell lung cancer

BACKGROUND

We aim to develop and test performance of a semi-automated method (computerized query combined with manual review) for chart abstraction in the identification and characterization of surveillance radiology imaging for post-treatment non-small cell lung cancer patients.

METHODS

A gold standard dataset consisting of 3011 radiology reports from 361 lung cancer patients treated at the Veterans Health Administration from 2008 to 2016 was manually created by an abstractor coding image type, image indication, and image findings. Computerized queries using a text search tool were performed to code reports. The primary endpoint of query performance was evaluated by sensitivity, positive predictive value (PPV), and F1 score. The secondary endpoint of efficiency compared semi-automated abstraction time to manual abstraction time using a separate dataset and the Wilcoxon rank-sum test.

RESULTS

Query for image type demonstrated the highest sensitivity of 85%, PPV 95%, and F1 score 0.90. Query for image indication demonstrated sensitivity 72%, PPV 70%, and F1 score 0.71. The image findings queries ranged from sensitivity 75-85%, PPV 23-25%, and F1 score 0.36-0.37. Semi-automated abstraction with our best performing query (image type) improved abstraction times by 68% per patient compared to manual abstraction alone (from median 21.5 min (interquartile range 16.0) to 6.9 min (interquartile range 9.5), p < 0.005).

CONCLUSIONS

Semi-automated abstraction using the best performing query of image type improved abstraction efficiency while preserving data accuracy. The computerized query acts as a pre-processing tool for manual abstraction by restricting effort to relevant images. Determining image indication and findings requires the addition of manual review for a semi-automatic abstraction approach in order to ensure data accuracy.

Spanish Society of Thoracic Surgery (SECT) consensus document. Long-term follow-up for operated patients with lung cancer

The most effective treatment for lung cancer is complete lung resection, although recurrences reach up to 10% and the appearance of second neoplasms, up to 6%. Therefore, the follow-up of these patients will be essential for the early detection and treatment of these events; however there is no definition of the form, time and cadence of these follow-ups. In this consensus document, we try to define them based on the available scientific evidence. A critical review of the literature is carried out (meta-analysis, systematic reviews, reviews, consensus recommendations of scientific societies, randomized controlled studies, non-randomized controlled studies, observational studies and case series studies) and communications to the main congresses on oncology and thoracic surgery in Spanish, English and French. The evidences found are classified following the GRADE system. It is defined according to the existing evidence that the patient resected for lung cancer should be followed up, as well as that this follow-up should be close during the first years and with CT (not being necessary to follow up with PET-CT, biomarkers or bronchoscopy). Cessation of smoking is also recommended in this follow-up.

[A Review of Current Knowledge for X-ray Energy in CT: Practical Guide for CT Technologist]

In computed tomography (CT) systems, the optimal X-ray energy in imaging depends on the material composition and the subject size. Among the parameters related to the X-ray energy, we can arbitrarily change only the tube voltage. For years, the tube voltage has often been set at 120 kVp. However, since about 2000, there has been an increasing interest in reducing radiation dose, and it has led to the publication of various reports on low tube voltage. Furthermore, with the spread of dual-energy CT, virtual monochromatic X-ray images are widely used since the contrast can be adjusted by selecting the optional energy. Therefore, because of the renewed interest in X-ray energy in CT imaging, the issue of energy and imaging needs to be summarized. In this article, we describe the basics of physical characteristics of X-ray attenuation with materials and its influence on the process of CT imaging. Moreover, the relationship between X-ray energy and CT imaging is discussed for clinical applications.

Spanish Society of Thoracic Surgery (SECT) consensus document. Long-term follow-up for operated patients with lung cancer

The most effective treatment for lung cancer is complete lung resection, although recurrences reach up to 10% and the appearance of second neoplasms, up to 6%. Therefore, the follow-up of these patients will be essential for the early detection and treatment of these events; however, there is no definition of the form, time and cadence of these follow-ups. In this consensus document, we try to define them based on the available scientific evidence. A critical review of the literature is carried out (meta-analysis, systematic reviews, reviews, consensus recommendations of scientific societies, randomized controlled studies, non-randomized controlled studies, observational studies and case series studies) and communications to the main congresses on oncology and thoracic surgery in Spanish, English and French. The evidences found are classified following the GRADE system. It is defined according to the existing evidence that the patient resected for lung cancer should be followed up, as well as that this follow-up should be close during the first years and with CT (not being necessary to follow up with PET-CT, biomarkers or bronchoscopy). Cessation of smoking is also recommended in this follow-up.

Guiding Principles in the Management of Synchronous and Metachronous Primary Non-Small Cell Lung Cancer

Multiple lung cancers can be found simultaneously, with incidence ranging from 1% to 8%. Documentation of more than 1 pulmonary lesion can be challenging, because these solid, ground-glass, or mixed-density tumors may represent multicentric malignant disease or intrapulmonary metastases. If mediastinal nodal and distant deposits are excluded, surgery should be contemplated. After surgical treatment of lung cancer, patients should be followed closely for an undetermined period of time. Good clinical judgment is of outmost importance in deciding which individuals will benefit from those surgical interventions and which are candidates for alternate therapies. Every case should be discussed in a multidisciplinary meeting.

Comparison of conventional chest x ray with a novel projection technique for ultra-low dose CT

PURPOSE

To compare a novel thick-slab projection technique for ultra-low dose computed tomography (CT; thoracic tomogram) with conventional chest x ray with respect to 13 diagnostic categories.

METHODS

With the approval of the institutional ethics board, a dataset was retrospectively collected of 22 consecutive patients who had undergone a clinically requested emergency room conventional chest x ray (CXR) and a same-day standard-of-care non-contrast CT. Scanner specific noise was added to the CT images to simulate a target dose of 0.18 mSv. A novel algorithm was used to post-process CT images as coronal isotropic reformats by applying a voxel-based, locally normalized weighted-intensity projection to generate 2 cm thick slabs with 1 cm overlap. Three chest radiologists with no prior training for the study reviewed the CXR and thoracic tomogram for each case and assessed each diagnostic category (pneumonic infiltrates, pulmonary edema, interstitial lung disease, nodules > 5 mm, nodules < 5 mm, pleural effusion, pericardial effusion, heart size, acute bone fractures, foreign bodies, pneumothorax, mediastinal vessel diameter, free abdominal air) on a Likert scale from -4 (definitely absent/normal) to +4 (definitely present/abnormal). MRMC ROC curves were generated for each category. Time for interpretation and subjective image quality score (0-10) were also assessed.

RESULTS

For focal lung disease (pneumonic infiltrates, nodules < 5 mm, nodules > 5mm), the area under the ROC curve (AUC) was significantly higher for thoracic tomograms than CXR (0.803 vs 0.648, respectively, P = 0.02). For non-focal lung disease (pulmonary edema, interstitial lung disease) and effusions (pulmonary, pericardial), the AUC was larger for thoracic tomograms than CXR but the difference did not reach significance (0.870 vs 0.833, P = 0.141; and 0.823 vs 0.752, P = 0.296, respectively). For acute bone fractures and foreign bodies, the AUC was smaller for thoracic tomograms than CXR, the difference was however not significant (0.491 vs 0.532, P = 0.42; and 0.871 vs 0.971, P = 0.39, respectively). Other diagnostic categories had no true positive cases in the dataset. The mean time for interpretation for each was 36.9 and 24.0 s with standard deviations of 0.857 and 5.977. The image quality score for each was 8.2 and 7.8 with standard deviations of 0.970 and 1.614.

CONCLUSION

Thoracic tomograms were found to be diagnostically superior to CXR for focal lung disease, at no increased radiation dose. The thoracic tomogram presents an opportunity to improve the standard-of-care for patients who would otherwise receive a conventional CXR.

Added benefits of early detection of other diseases on low-dose CT screening

Low-dose CT screening for lung cancer provides images of the entire chest and upper abdomen. While the focus of screening is on finding early lung cancer, radiology leadership has embraced the fact that the information contained in the images presents a new challenge to the radiology profession. Other findings in the chest and upper abdomen were not the reason for obtaining the screening CT scan, nor symptom-prompted, but still need to be reported. Reporting these findings and making recommendations for further workup requires careful consideration to avoid unnecessary workup or interventions while still maximizing the benefit that early identification of these other diseases provided. Other potential findings, such as cardiovascular disease and chronic pulmonary obstructive diseases actually cause more deaths than lung cancer. Existing recommendations for workup of abnormal CT findings are based on symptom-prompted indications for imaging. These recommendations may be different when the abnormalities are identified in asymptomatic people undergoing CT screening for lung cancer. I-ELCAP, a large prospectively collected multi-institutional and multi-national database of screenings, was used to analyze CT findings identified in screening for lung cancer. These analyses and recommendations were made by radiologists in collaboration with clinicians in different medical specialties.

The Regimen of Computed Tomography Screening for Lung Cancer: Lessons Learned Over 25 Years From the International Early Lung Cancer Action Program

We learned many unanticipated and valuable lessons since we started planning our study of low-dose computed tomography (CT) screening for lung cancer in 1991. The publication of the baseline results of the Early Lung Cancer Action Project (ELCAP) in Lancet 1999 showed that CT screening could identify a high proportion of early, curable lung cancers. This stimulated large national screening studies to be quickly started. The ELCAP design, which provided evidence about screening in the context of a clinical program, was able to rapidly expand to a 12-institution study in New York State (NY-ELCAP) and to many international institutions (International-ELCAP), ultimately working with 82 institutions, all using the common I-ELCAP protocol. This expansion was possible because the investigators had developed the ELCAP Management System for screening, capturing data and CT images, and providing for quality assurance. This advanced registry and its rapid accumulation of data and images allowed continual assessment and updating of the regimen of screening as advances in knowledge and new technology emerged. For example, in the initial ELCAP study, introduction of helical CT scanners had allowed imaging of the entire lungs in a single breath, but the images were obtained in 10 mm increments resulting in about 30 images per person. Today, images are obtained in submillimeter slice thickness, resulting in around 700 images per person, which are viewed on high-resolution monitors. The regimen provides the imaging acquisition parameters, imaging interpretation, definition of positive result, and the recommendations for further workup, which now include identification of emphysema and coronary artery calcifications. Continual updating is critical to maximize the benefit of screening and to minimize potential harms. Insights were gained about the natural history of lung cancers, identification and management of nodule subtypes, increased understanding of nodule imaging and pathologic features, and measurement variability inherent in CT scanners. The registry also provides the foundation for assessment of new statistical techniques, including artificial intelligence, and integration of effective genomic and blood-based biomarkers, as they are developed.

Extent of resection and lymph node evaluation in early stage metachronous second primary lung cancer: a population-based study

BACKGROUND

Evidence of the optimal surgery strategy for early stage metachronous second primary lung cancer (SPLC) has been limited and controversial. This study aims to compare the survival outcomes of different extents of resection and lymph node evaluation in these patients.

METHODS

Early stage metachronous SPLC patients, who had received lobectomy for initial primary lung cancer (IPLC) and developed SPLC more than 3 months later, were selected from the Surveillance, Epidemiology, and End Results (SEER) database according to the American College of Chest Physicians (ACCP) guideline. Overall survival (OS) and lung cancer-specific survival (CSS) of different extents of resection and lymph node evaluation were analyzed using Kaplan-Meier method and multivariate Cox regression model.

RESULTS

Overall, 1,784 SPLC patients without nodal or distant metastasis were identified. Lobectomy was associated with significantly longer OS (HR: 0.83, 95% CI: 0.71-0.97, 5-year survival: 59.2% vs. 53.3%, P=0.02) and CSS (HR: 0.72, 95% CI: 0.60-0.88, 5-year survival: 71.5% vs. 63.2%, P=0.001) compared with sublobar resection. In addition, examined lymph node number ≥10 demonstrated longer OS (HR: 0.63, 95% CI: 0.50-0.81, 5-year survival: 66.6% vs. 53.9%, P<0.001) and CSS (HR: 0.54, 95% CI: 0.40-0.74, 5-year survival: 77.4% vs. 64.7%, P<0.001) compared with an examined lymph node number <10. The survival benefits of lobectomy and examined lymph node number ≥10 were further validated in multivariate Cox regression and subgroup analysis stratified by tumor size.

CONCLUSIONS

Lobectomy and thorough lymph node evaluation provided significantly longer survival, and thus should be considered for early stage metachronous SPLC whenever possible.

Added Value of Ultra-low-dose Computed Tomography, Dose Equivalent to Chest X-Ray Radiography, for Diagnosing Chest Pathology

Purpose:

The purpose of this study was to assess the clinical value of ultra–low-dose computed tomography (ULDCT) compared with chest x-ray radiography (CXR) for diagnosing chest pathology.

Materials and Methods:

A total of 200 patients referred for CXR by outpatient clinics or general practitioners were enrolled prospectively. They underwent CXR (posteroanterior and lateral) and ULDCT (120 kV, 3 mAs) on the same day. In-room time and effective dose were recorded for each examination. Studies were categorized whether they were diagnostic or not, relevant radiologic diagnostic findings were reported, and confidence for diagnosis was recorded by a Likert scale. Differences in diagnostic confidence and effect on management decision were compared.

Results:

In-room time was <2 minutes for CXR and <3 minutes for ULDCT. Effective dose was 0.040 mSv for CXR and 0.071 mSv for ULDCT. CXR was considered diagnostic in 98% and ULDCT in 100%. The mean perceived confidence for diagnosis was 88±12% with CXR and 98±2% with ULDCT (P<0.0001), whereas discrepant findings between CXR and ULDCT were found in 101 of 200 patients. As compared with CXR, ULDCT had added value for management decisions in 40 of 200 patients.

Conclusions:

ULDCT provided added value to the radiologist by improved perceived confidence with a reduction in false-positive and false-negative CXR investigations that had management implications in 20% of patients. The effective dose of ULDCT will not be a limiting factor for introducing ULDCT of the chest on a broad scale in clinical practice.

Potential for the blood-based biomarkers cytokeratin 19 fragment (CYFRA 21-1) and human epididymal protein 4 (HE4) to detect recurrence during monitoring after surgical resection of adenocarcinoma of the lung

OBJECTIVES

The biomarkers cytokeratin 19 fragment (CYFRA 21-1) and human epididymis protein 4 (HE4) are useful in the diagnosis, prognosis, and monitoring of non-small cell lung cancer (NSCLC), but their combination has not been investigated yet. The objective of this analysis was to evaluate the ability of CYFRA 21-1 and HE4 to predict recurrence as part of follow-up monitoring in patients with adenocarcinoma (ADC) of the lung.

MATERIALS AND METHODS

Serum samples were collected from patients with stage I-IIIA ADC preoperatively and during follow-up at 3, 6, 12, 18, and 24 months and then every 6-12 months up to 5 years post-R0 resection. Samples were analyzed for CYFRA 21-1 and HE4 via electrochemiluminescence immunoassay. All cases of disease recurrence were verified by imaging. The diagnostic performance of CYFRA 21-1, HE4, and their combination to predict recurrence was assessed by Receiver Operating Characteristic (ROC) and corresponding area under the curve (AUC).

RESULTS

115 patients with ADC were included (N = 612 biomarker measurements); median age was 63 years; most had stage I-II disease (n = 97; 84.3%). All patients underwent surgical resection; 44 patients (38%) also received adjuvant chemotherapy and 16 (14%) received radiation therapy. At the median timepoint for the last blood sample collection (37 months), 31 patients (27%) had experienced recurrence. Both CYFRA 21-1 and HE4 were able to detect recurrence (AUC and 95% confidence interval [CI]): 75.9% (66.0-85.8%) and 75.4% (65.9-84.8%), respectively, but this increased with the combination (78.8% [69.0-88.6%]). At a sensitivity of 80%, the respective specificities (95% CI) for CYFRA 21-1, HE4, and the combination were 57.1% (53.0-61.2%), 57.1% (53.0-61.2%), and 69.7% (65.8-73.4%).

CONCLUSION

Serial measurements of serum CYFRA 21-1 and HE4 levels could provide a valuable method for follow-up monitoring of patients with ADC to detect recurrence.

Ultra-low-dose unenhanced chest CT: Prospective comparison of high kV/low mA versus low kV/high mA protocols

PURPOSE

To qualitatively and quantitatively compare unenhanced ultra-low-dose chest computed tomography (ULD-CT) acquired at 80kVp and 135kVp.

MATERIALS AND METHODS

Fifty-one patients referred for unenhanced chest CT were prospectively included. There were 29 men and 22 women, with a mean age of 64.7±11.6 (SD) years (range: 35-91 years) and a mean body mass index of 26.2±6.3 (SD) (range: 17-54.9). All patients underwent two different ULD-CT protocols (80kVp-40mA and 135kVp-10mA). Image quality of both ULD-CT examinations using a 5-level scale as well as assessability of 6 predetermined lung parenchyma lesions were blindly evaluated by three radiologists and compared using a logistic regression model. Image noise of the two protocols was compared with Wilcoxon signed-rank test.

RESULTS

The mean dose-length product at 80kVp and at 135kVp were 14.7±1.8 (SD) mGy.cm and 15.6±1.9 (SD) mGy.cm, respectively (P<0.001). Image noise was significantly lower at 135kVp (58.9±12.4) than at 80kVp (74.7±14.5) (P<0.001). For all readers and for all examinations, the 135kVp protocol yielded better image quality than 80kVp protocol, with a mean qualitative score of 4.5±0.7 versus 3.9±0.8 (P<0.001). The 135kVp protocol was significantly more often of diagnostic quality than the 80kvp protocol (92.3% versus 77.8%, respectively) (P<0.001) and was less prone to image quality deterioration in obese patients. Parenchymal lesions were never better depicted on the 80kVp protocol than with the 135kVp protocol.

CONCLUSION

Unenhanced chest ULD-CT should be acquired at a high kilovoltage and low current, such as 135kVp-10mA, over a low kilovoltage and high current protocol.

More Frequent Surveillance Following Lung Cancer Resection Is Not Associated With Improved Survival: A Nationally Representative Cohort Study

OBJECTIVE

To evaluate whether an association exists between the intensity of surveillance following surgical resection for non-small cell lung cancer (NSCLC) and survival.

BACKGROUND

Surveillance guidelines following surgical resection of NSCLC vary widely and are based on expert opinion and limited evidence.

METHODS

A Special Study of the National Cancer Database randomly selected stage I to III NSCLC patients for data reabstraction. For patients diagnosed between 2006 and 2007 and followed for 5 years through 2012, registrars documented all postsurgical imaging with indication (routine surveillance, new symptoms), recurrence, new primary cancers, and survival, with 5-year follow-up. Patients were placed into surveillance groups according to existing guidelines (3-month, 6-month, annual). Overall survival and survival after recurrence were analyzed using Cox Proportional Hazards Models.

RESULTS

A total of 4463 patients were surveilled with computed tomography scans; these patients were grouped based on time from surgery to first surveillance. Groups were similar with respect to age, sex, comorbidities, surgical procedure, and histology. Higher-stage patients received more surveillance. More frequent surveillance was not associated with longer risk-adjusted overall survival [hazard ratio for 6-month: 1.16 (0.99, 1.36) and annual: 1.06 (0.86-1.31) vs 3-month; P value 0.14]. More frequent imaging was also not associated with postrecurrence survival [hazard ratio: 1.02/month since imaging (0.99-1.04); P value 0.43].

CONCLUSIONS

These nationally representative data provide evidence that more frequent postsurgical surveillance is not associated with improved survival. As the number of lung cancer survivors increases over the next decade, surveillance is an increasingly important major health care concern and expenditure.

Playing the odds: lung cancer surveillance after curative surgery

PURPOSE OF REVIEW

After 'curative' resection, many patients are still at risk for further lung cancer, either as a recurrence or a new metachronous primary. In theory, close follow-up should improve survival by catching relapse early - but in reality, many experts feel that surveillance for recurrence is of uncertain value. In this article, we explore the reasons behind the controversy, what the current guidelines recommend, and what future solutions are in development that may ultimately resolve this debate.

RECENT FINDINGS

Although postoperative surveillance for a new lung cancer may impart a survival advantage, this benefit does not appear to extend to the phenomenon of recurrence. Nevertheless, close radiographic follow-up after curative resection is still recommended by most professional societies, with more frequent scanning in the first 2 years, and then annual screening thereafter. Given the radiation risk, however, low-dose and minimal-dose computed tomography options are under investigation, as well as timing scans around expected peaks of recurrence rather than a set schedule.

SUMMARY

Applying the same surveillance algorithm to all lung cancer patients after curative resection may not be cost-effective or reasonable, especially if there is no demonstrable mortality benefit. Therefore, future research should focus on finding safer nonradiographic screening options, such as blood or breath biomarkers, or developing nomograms for predicting which patients will relapse and require closer follow-up. Ultimately, however, better tools for surveillance may be moot until we develop better treatment options for lung cancer recurrence.

[What future for chest x-ray against ultra-low-dose computed tomography?]

Technological improvements, with iterative reconstruction at the foreground, have lowered the radiation dose of a chest CT close to that of a PA and lateral chest x-ray. This ultra-low dose chest CT (ULD-CT) has an image quality that is degraded on purpose, yet remains diagnostic in many clinical indications. Thus, its effectiveness is already validated for the detection and the monitoring of solid parenchymal nodules, for the diagnosis and monitoring of infectious lung diseases and for the screening of pleural lesions secondary to asbestos exposure. Its limitations are the analysis of the mediastinal structures, the severe obesity (BMI>35) and the detection of interstitial lesions. If it can replace the standard chest CT in these indications, all the more in situations where radiation dose is a major problem (young patients, repeated exams, screening), it progressively emerges as a first line alternative for chest radiograph, providing more data at a similar radiation cost.

A method to assess image quality for Low-dose PET: analysis of SNR, CNR, bias and image noise

Background

Lowering injected dose will have an effect on PET image quality. In this article, we aim to investigate this effect in terms of signal-to-noise ratio (SNR) in the liver, contrast-to-noise ratio (CNR) in the lesion, bias and ensemble image noise.

Methods

We present here our method and preliminary results using tuberculosis (TB) cases. Sixteen patients who underwent ¹⁸F-FDG PET/MR scans covering the whole lung and portion of the liver were selected for the study. Reduced doses were simulated by randomly discarding events in the PET list mode data stream, and ten realizations at each simulated dose were generated and reconstructed. The volumes of interest (VOI) were delineated on the image reconstructed from the original full statistics data for each patient. Four thresholds (20, 40, 60 and 80 % of SUVmax) were used to quantify the effect of the threshold on CNR at the different count level. Image metrics were calculated for each VOI. This experiment allowed us to quantify the loss of SNR and CNR as a function of the counts in the scan, in turn related to dose injected. Reproducibility of mean and maximum standardized uptake value (SUVmean and SUVmax) measurement in the lesions was studied as standard deviation across 10 realizations.

Results

At 5 × 10⁶ counts in the scan, the average SNR in the liver in the observed samples is about 3, and the CNR is reduced to 60 % of the full statistics value. The CNR in the lesion and SNR in the liver decreased with reducing count data. The variation of CNR across the four thresholds does not significantly change until the count level of 5 × 10⁶. After correcting the factor related to subject’s weight, the square of the SNR in the liver was found to have a very good linear relationship with detected counts. Some quantitative bias appears with count reduction. At the count level of 5 × 10⁶, bias and noise in terms of SUVmean and SUVmax are up to 10 and 20 %, respectively. To keep both bias and noise less than 10 %, 5 × 10⁶ counts and 20 × 10⁶ counts were required for SUVmean and SUVmax, respectively.

Conclusions

Initial results with the given data of 16 patients diagnosed as TB demonstrated that 5 × 10⁶ counts in the scan could be sufficient to yield good images in terms of SNR, CNR, bias and noise. In the future, more work needs to be done to validate the proposed method with a larger population and lung cancer patient data.

Exhaled breath condensate for lung cancer protein analysis: a review of methods and biomarkers

Lung cancer is a leading cause of cancer-related deaths worldwide, and is considered one of the most aggressive human cancers, with a 5 year overall survival of 10-15%. Early diagnosis of lung cancer is ideal; however, it is still uncertain as to what technique will prove successful in the systematic screening of high-risk populations, with the strongest evidence currently supporting low dose computed tomography (LDCT). Analysis of exhaled breath condensate (EBC) has recently been proposed as an alternative low risk and non-invasive screening method to investigate early-stage neoplastic processes in the airways. However, there still remains a relative paucity of lung cancer research involving EBC, particularly in the measurement of lung proteins that are centrally linked to pathogenesis. Considering the ease and safety associated with EBC collection, and advances in the area of mass spectrometry based profiling, this technology has potential for use in screening for the early diagnosis of lung cancer. This review will examine proteomics as a method of detecting markers of neoplasia in patient EBC with a particular emphasis on LC, as well as discussing methodological challenges involving in proteomic analysis of EBC specimens.

Normalization of Exhaled Carbonyl Compounds After Lung Cancer Resection

Background

Quantitative analysis of specific exhaled carbonyl compounds (ECCs) has shown promise for the detection of lung cancer. The purpose of this study is to demonstrate the normalization of ECCs in patients after lung cancer resection.

Methods

Patients from a single center gave consent and were enrolled in the study from 2011 onward. Breath analysis was performed on lung cancer patients before and after surgical resection of their tumors. One liter of breath from a single exhalation was collected and evacuated over a silicon microchip. Carbonyls were captured by oximation reaction and analyzed by mass spectrometry. Concentrations of four cancer-specific ECCs were measured and compared by using the Wilcoxon test. A given cancer marker was considered elevated at 1.5 or more standard deviations greater than the mean of the control population.

Results

There were 34 cancer patients with paired samples and 187 control subjects. The median values after resection were significantly lower for all four ECCs and were equivalent to the control patient values for three of the four ECCs.

Conclusions

The analysis of ECCs demonstrates reduction to the level of control patients after surgical resection for lung cancer. This technology has the potential to be a useful tool to detect disease after lung cancer resection. Continued follow-up will determine whether subsequent elevation of ECCs is indicative of recurrent disease.

[Ultra-low dose chest CT: The end of chest radiograph?]

Ultra-low dose chest CT (ULD-CT) is acquired at a radiation dose lowered to that of a PA and lateral chest X-ray. Its image quality is degraded, yet remains diagnostic in many clinical indications. Technological improvements, with iterative reconstruction at the foreground, allowed a strong increase in the image quality obtained with this examination, which is achievable on most recent (<5 years) scanner. Established clinical indications of ULD-CT are increasing, and its non-inferiority compared to the reference "full dose" chest CT are currently demonstrated for the detection of solid nodules, for asbestos-related pleural diseases screening and for the monitoring of infectious pneumonia. Its current limitations are the obese patients (BMI>35) and the interstitial pneumonia, situations in which their performances are insufficient.

Survival Prediction Model Using Clinico-Pathologic Characteristics for Nonsmall Cell Lung Cancer Patients After Curative Resection

The current TNM staging system did not provide disease relapse information. The aim of study was try to establish a predictive survival model for disease and overall survival in nonsmall cell lung cancer patients who presented as resectable disease and to develop a reference for follow-up imaging tool selection.From January 2005 to December 2011, 442 patients who initially presented as resectable disease (stages I-IIIa) and received anatomic resection and mediastinal lymph node dissection were included in the study.Medical charts were thoroughly reviewed and clinico-pathologic factors were collected and analyzed.Visceral pleural invasion, tumor size >5 cm, and postoperative adjuvant therapy were identified as risk factors for poorer disease-free survival. The 5-year disease-free survival from score 0 to 3 was 68.7%, 46.6%, 31.9%, and 26.1%, respectively. The disease relapse percentage for scores 0 to 3 were 26.49%, 50.61%, 65.05%, and 73.81%, respectively. For analysis of overall survival, age >60 years, tumor size >3 cm, and total metastatic lymph node ratio >0.05 were correlated to worse overall survival. Because greater age may be correlated with poor general condition, we re-scored risk factors that correlated to disease severity that ranging from 0 to 2. The 5-year overall survival range from score 0 to 2 was 56.3%, 43.1%, and 13.1%, respectively.Poor prognostic factors correlated to disease-free survival were tumor size >5 cm, visceral pleural invasion, and patients needing to receive postoperative adjuvant therapy. Disease-free survival of resectable nonsmall cell lung cancer patients and disease relapse can be stratified by these 3 factors. Chest tomography may be recommended for patients with 1 or more poor disease-free survival risk factors.

Second primary lung cancers following a diagnosis of primary head and neck cancer

OBJECTIVES

Second primary lung cancers (SPLC) are not uncommon in survivors of squamous cell head and neck cancer (HNSCC), and carry a worse prognosis than when patients present with a primary lung cancer. We reviewed our institutional experience on the treatment and prognosis of SPLC patients, both at the time of diagnosis, and following treatment of HNSCC, in order to explore treatment outcomes.

MATERIALS AND METHODS

Our institutional database was queried for patients with a diagnosis of HNSCC and lung cancer, between 2000 and 2013. Only HNSCC patients with tumors of the oral cavity, oropharynx, hypopharynx and larynx were eligible. Patients were stratified between synchronous and metachronous HNSCC and SPLC. Cox regression analysis was performed to determine factors predictive of overall survival (OS) in metachronous presentations.

RESULTS

181 eligible patients were identified for analysis, comprising 40 synchronous and 141 metachronous HNSCC-SPLC. Patients presenting with synchronous SPLC were more likely to have early-stage disease, as compared to patients with metachronous SPLC (45% vs. 28%, respectively; p=0.036). Patients with early stage SPLC had a significantly better survival compared to those with locally advanced (p<0.001) and metastatic disease (p<0.001), with a median OS of 95.4 months vs. 11.0 and 4.6 months, respectively.

CONCLUSIONS

Although the survival of patients treated for early-stage NSCLC were good, the OS of the entire cohort of SPLC after HNSCC was poor as a majority of patients presented with advanced disease. The use of CT screening strategies in this patient population warrants further investigation.

How to follow up patients after curative resection of lung cancer

Survivors of lung cancer surgery are among the highest-risk patients for developing another lung cancer, yet there is no clear consensus on the method of surveillance for patients after curative surgical resection. Surveillance is no longer futile because the emergence of computed tomography screening has allowed the detection of recurrences and new metachronous cancers at an early stage. In selected patients, lung cancer identified recently on routine computed tomography scan is amenable to curative treatment and is associated with longer survival.

Does the method of radiologic surveillance affect survival after resection of stage I non-small cell lung cancer?

OBJECTIVES

Controversy persists regarding appropriate radiographic surveillance strategies after lung cancer resection. We compared the impact of surveillance computed tomography scan versus chest radiography in patients who underwent resection for stage I lung cancer.

METHODS

A retrospective analysis was performed of all patients undergoing resection for pathologic stage I lung cancer from January 2000 to April 2013. After resection, follow-up included routine history and physical examination in conjunction with chest radiography or computed tomography at the discretion of the treating physician. Identification of successive lung malignancy (ie, recurrence at any new site or new primary) and survival were recorded.

RESULTS

There were 554 evaluable patients, with 232 receiving routine postoperative computed tomography and 322 receiving routine chest radiography. Postoperative 5-year survival was 67.8% in the computed tomography group versus 74.8% in the chest radiography group (P = .603). Successive lung malignancy was found in 27% (63/232) of patients receiving computed tomography versus 22% (72/322) receiving chest radiography (P = .19). The mean time from surgery to diagnosis of successive malignancy was 1.93 years for computed tomography versus 2.56 years for chest radiography (P = .046). For the computed tomography group, 41% (26/63) of successive malignancies were treated with curative intent versus 40% (29/72) in the chest radiography group (P = .639). Cox proportional hazard analysis indicated imaging modality (computed tomography vs chest radiography) was not associated with survival (P = .958).

CONCLUSIONS

Surveillance computed tomography may result in earlier diagnosis of successive malignancy versus chest radiography in stage I lung cancer, although no difference in survival was demonstrated. A randomized trial would help determine the impact of postoperative surveillance strategies on survival.