Emphysema phenotypes and lung cancer risk

BACKGROUND

To assess the relationship between lung cancer and emphysema subtypes.

OBJECTIVE

Airflow obstruction and emphysema predispose to lung cancer. Little is known, however, about the lung cancer risk associated with different emphysema phenotypes. We assessed the risk of lung cancer based on the presence, type and severity of emphysema, using visual assessment.

METHODS

Seventy-two consecutive lung cancer cases were selected from a prospective cohort of 3,477 participants enrolled in the Clínica Universidad de Navarra's lung cancer screening program. Each case was matched to three control subjects using age, sex, smoking history and body mass index as key variables. Visual assessment of emphysema and spirometry were performed. Logistic regression and interaction model analysis were used in order to investigate associations between lung cancer and emphysema subtypes.

RESULTS

Airflow obstruction and visual emphysema were significantly associated with lung cancer (OR = 2.8, 95%CI: 1.6 to 5.2; OR = 5.9, 95%CI: 2.9 to 12.2; respectively). Emphysema severity and centrilobular subtype were associated with greater risk when adjusted for confounders (OR = 12.6, 95%CI: 1.6 to 99.9; OR = 34.3, 95%CI: 25.5 to 99.3, respectively). The risk of lung cancer decreases with the added presence of paraseptal emphysema (OR = 4.0, 95%CI: 3.6 to 34.9), losing this increased risk of lung cancer when it occurs alone (OR = 0.7, 95%CI: 0.5 to 2.6).

CONCLUSIONS

Visual scoring of emphysema predicts lung cancer risk. The centrilobular phenotype is associated with the greatest risk.

Definitive Radiation for Stage I Lung Cancer in a Screened Population: Results From the I-ELCAP

PURPOSE

The International Early Lung Cancer Action Program is a cohort study to assess the cure rate of participants undergoing annual low-dose computed tomography screening for lung cancer. This study compares the characteristics and outcomes of patients who received a diagnosis of clinical stage I non-small cell lung carcinoma (NSCLC) treated with definitive radiation therapy and surgical resection.

METHODS AND MATERIALS

Patient information was drawn from the International Early Lung Cancer Action Program database from 1992 to 2017. All instances in which treatment was performed for histologically proven stage I NSCLC using definitive radiation therapy and surgery were identified. The home institution determined radiation plans. Patient characteristics and Kaplan-Meier lung cancer-specific (LCS) long-term survival rates were compared for both types of treatment. Follow-up time was calculated from time of diagnosis until death from lung cancer, loss to follow-up, or December 31, 2017, whichever came earlier.

RESULTS

Among 82,628 baseline and 109,250 annual repeat screenings, 853 patients received a diagnosis of clinical stage I NSCLC, of whom 31 (3.6%) were treated by definitive radiation therapy and 702 (82.3%) by surgical resection alone. Radiation therapy prescription information was obtainable for 24 of the 31 patients: The median dose was 54.5 Gy, the median number of fractions was 5, and 17 patients were treated using stereotactic body radiation therapy. LCS survival rates were not significantly different for radiation therapy compared with surgery: 90.0% (95% confidence interval, 84.9%-100.0%) versus 94.8% (95% confidence interval, 93.0%-96.6%) (P = .09). Median follow-up time was 9.7 years for all, but it was shorter for those treated by radiation therapy than for those who underwent surgery (4.3 vs 10.0 years, P < .0001).

CONCLUSIONS

The majority of patients identified by computed tomography screening were treated with surgical resection. Despite being older and having more comorbidities, LCS long-term survival rates of patients treated with definitive radiation therapy were not significantly different compared with survival rates of patients treated with surgery alone. Radiation therapy appears to be a viable alternative to surgery for screen-diagnosed patients with lung cancer.

A Review of Quality of Life Measures used in Surgical Outcomes for Stage I Lung Cancers

This review summarizes the literature on QoL in early stage lung cancer patients who underwent surgery. PubMed and PsycINFO were searched. Twelve articles from 10 distinct studies were identified for a total of 992 patients. Five QoL measures were used. One study reported only on pre-surgical QoL, six only on post-surgical QoL and three studies reported on both pre- and post-surgical QoL. Timing for the administration of post-surgical QoL surveys varied. The literature on QoL in Stage I non-small-cell lung cancer patients is very sparse. Additional research is needed to explore the impact of different surgical approaches on QoL.

Updating the role of FDG PET/CT for evaluation of lung cancer manifesting in nonsolid nodules

PURPOSE

To assess the feasibility of using CT to correct specific uptake values (SUVs) for fluorodeoxyglucose (FDG) in patients with nonsolid nodules.

METHODS

Patients with FDG-PET/CT and thin-section CT were included in this pilot study. Thirty-five adenocarcinomas manifesting as nonsolid nodules were classified into two groups; 90-100% and 1-89% lepidic component. SUVmax was corrected based on the CT determination of the proportion of soft tissue component within the cancer (SUVatt).

RESULTS

Both SUVmax and SUVatt increased as the percentage of the lepidic component decreased. SUVmax and SUVatt were significantly different between the groups.

CONCLUSION

Extent of invasiveness of nonsolid cancers (as a marker of aggressiveness) can potentially be quantified by PET/CT using a correction method that accounts for the proportion of soft tissue within the tumor.

Correction to: Baseline and annual repeat rounds of screening: implications for optimal regimens of screening

The original version of this article unfortunately contained a mistake. The conflict of interest was incorrect.

Controversies on lung cancers manifesting as part-solid nodules

PURPOSE

Summarise survival of patients with resected lung cancers manifesting as part-solid nodules (PSNs).

METHODS

PubMed/MEDLINE and EMBASE databases were searched for all studies/clinical trials on CT-detected lung cancer in English before 21 December 2015 to identify surgically resected lung cancers manifesting as PSNs. Outcome measures were lung cancer-specific survival (LCS), overall survival (OS), or disease-free survival (DFS). All PSNs were classified by the percentage of solid component to the entire nodule diameter into category PSNs <80% or category PSNs ≥80%.

RESULTS

Twenty studies reported on PSNs <80%: 7 reported DFS and 2 OS of 100%, 6 DFS 96.3-98.7%, and 11 OS 94.7-98.9% (median DFS 100% and OS 97.5%). Twenty-seven studies reported on PSNs ≥80%: 1 DFS and 2 OS of 100%, 19 DFS 48.0%-98.0% (median 82.6%), and 16 reported OS 43.0%-98.0% (median DFS 82.6%, OS 85.5%). Both DFS and OS were always higher for PSNs <80%.

CONCLUSION

A clear definition of the upper limit of solid component of a PSN is needed to avoid misclassification because cell-types and outcomes are different for PSN and solid nodules. The workup should be based on the size of the solid component.

KEY POINTS

• Lung cancers manifesting as PSNs are slow growing with high cure rates. • Upper limits of the solid component are important for correct interpretation. • Consensus definition is important for the management of PSNs. • Median disease-free-survival (DFS) increased with decreasing size of the nodule.

Quality assurance and quantitative imaging biomarkers in low-dose CT lung cancer screening

After years of assessment through controlled clinical trials, low-dose CT screening for lung cancer is becoming part of clinical practice. As with any cancer screening test, those undergoing lung cancer screening are not being evaluated for concerning signs or symptoms, but are generally in good health and proactively trying to prevent premature death. Given the resultant obligation to achieve the screening aim of early diagnosis while also minimizing the potential for morbidity from workup of indeterminate but ultimately benign screening abnormalities, careful implementation of screening with conformance to currently recognized best practices and a focus on quality assurance is essential. In this review, we address the importance of each component of the screening process to optimize the effectiveness of CT screening, discussing options for quality assurance at each step. We also discuss the potential added advantages, quality assurance requirements and current status of quantitative imaging biomarkers related to lung cancer screening. Finally, we highlight suggestions for improvements and needs for further evidence in evaluating the performance of CT screening as it transitions from the research trial setting into daily clinical practice.

The Impact of Margins on Outcomes After Wedge Resection for Stage I Non-Small Cell Lung Cancer

BACKGROUND

The relationship between margin distance and recurrence and survival for stage I non-small cell lung carcinoma (NSCLC) less than or equal to 2 cm is not clear.

METHODS

Patient clinicopathologic data were reviewed from a pooled data set of stage I NSCLC lesions less than or equal to 2 cm resected by wedge resection at Brigham and Women's Hospital (BWH) between 2000 and 2005 and the International Early Lung and Cardiac Action Program (I-ELCAP) between 1999 and 2015. Multivariable models were constructed to evaluate the relationship between margin distance and recurrence and survival, adjusting for patient age, sex, tumor size, and histologic type. Optimal margin distance was determined for recurrence-free and overall survival using maximum χ² values among survival distributions.

RESULTS

Of 182 cases, 138 tumors had margin distance reported (113 BWH and 25 I-ELCAP). The average tumor size was 13.3 mm, and margin distance was 8.3 mm. During a mean follow-up of 49.6 months, there were 33 recurrences and 59 deaths. Increased margin distance was independently associated with lower risk of recurrence (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.83-0.98). Margin distance was also independently associated with longer survival (hazard ratio [HR], 0.94; 95% CI, 0.90-0.98). A margin distance greater than 9 mm was associated with longest recurrence-free survival and a margin distance greater than 11 mm was associated with longest overall survival.

CONCLUSIONS

Increased margin distance was independently associated with lower risk of recurrence and longer overall survival in patients undergoing wedge resection for NSCLC tumors less than or equal to 2 cm. These findings suggest that with a minimum appropriate margin distance, wedge resection may yield outcomes comparable to those of lobectomy.

Hepatic steatosis in participants in a program of low-dose CT screening for lung cancer

OBJECTIVE

Determine the frequency of moderate-to-severe hepatic steatosis (HS) in asymptomatic participants in a low-dose CT (LDCT) screening program for lung cancer, to identify risk factors, and develop recommendations.

METHODS

Baseline LDCT scans of the chest of 170 participants in an IRB-approved study between August 2011 and April 2016 were reviewed. Demographic variables, comorbidities, and liver function tests were documented. Hepatic and splenic attenuation values hounsfield unit (HU) were measured. Regression analyses were performed.

RESULTS

Average liver attenuation was 57.6HU (standard deviation (SD) 9.3) and average liver/spleen (L/S) ratio was 1.3 (SD 0.3). Liver attenuation was <40HU for 9 (5.3%), liver/spleen (L/S) ratio <0.8 for 6 (3.5%), and either <40HU or L/S ratio <0.8 for 9 (5.3%). Male sex (p=0.004), diabetes (p=0.0005), emphysema (p=0.03), and high BMI (p=0.0006) were significant predictors of HS. Aspartate aminotransferase (p=0.0018) and alanine aminotransferase (p=0.012) were negatively correlated with liver attenuation. Reduced serum levels of alpha-1-antitrypsin may be a common factor of emphysema and HS.

CONCLUSION

LDCT can detect HS in asymptomatic participants with frequencies similar to previous reports. If liver attenuation is below 40HU and/or L/S ratio below 0.8, further evaluation of HS to the primary care physician or liver specialist is recommended.

Pulmonary abnormalities as a result of exposure to Libby amphibole during childhood and adolescence-The Pre-Adult Latency Study (PALS)

BACKGROUND

The purpose of Pre-Adult Latency Study was to evaluate lung findings among adults who had been environmentally exposed to Libby Amphibole only during childhood and adolescence.

METHODS

Recruitment was restricted to volunteers who attended primary and/or secondary school, lived in Libby, MT, prior to age 23 years for males and 21 years for females and subsequently left the area. Subjects completed exposure and respiratory questionnaires, underwent pulmonary function tests (PFTs), and chest CT scans. A Pleural Score was calculated for degree and extent of pleural thickening. Logistic regression and multivariate linear regression were used.

RESULTS

Of the 219 who met inclusion criteria, 198 participated. Pleural thickening was found in 96 (48%) of 198 participants. In almost half of these, it was of the lamellar type, not generally seen in exposure to other asbestos. Environmental Libby amphibole exposure was associated with pleural thickening, and the likelihood of pleural thickening increased with the number of years lived in the area. An inverse association between Pleural Score and PFT was found, which remained significant for FVC and DLco after additional sensitivity analyses.

CONCLUSIONS

Cumulative environmental exposure was associated with risk of pleural thickening. Among this cohort, quantitative measures of pleural thickening were associated with decreased PFT. Am. J. Ind. Med. 60:20-34, 2017. © 2016 Wiley Periodicals, Inc.

The Association of Secondhand Tobacco Smoke and CT Angiography-Verified Coronary Atherosclerosis

OBJECTIVES

The aim of this study was to assess the relationship of the extent of atherosclerosis on coronary computed tomographic angiography to the extent of secondhand tobacco smoke (SHTS) exposure in asymptomatic never smokers.

BACKGROUND

A dose-related association between SHTS and coronary artery calcium has been reported, but the total extent of atherosclerosis has not been investigated.

METHODS

A total of 268 never smokers, ages 40 to 80 years, completed a questionnaire assessing risk factors and extent of lifetime SHTS exposure, providing a total SHTS exposure score. Ordinal coronary artery calcium scores were derived from low-dose nongated computed tomographic scans, followed by computed tomographic angiography. Analyses of the prevalence, extent, and plaque characteristics of atherosclerosis were performed, and the independent contribution of SHTS, adjusted for other documented risk factors, was determined.

RESULTS

Coronary atherosclerosis was noted in 48% and was more frequent with low to moderate and high versus minimal SHTS exposure (48% and 69% vs. 25%; p < 0.0001). Adjusted odds ratios for any atherosclerosis were 2.1 (95% confidence interval: 1.0 to 4.4; p = 0.05) for low to moderate and 3.5 (95% confidence interval: 1.4 to 8.5; p = 0.01) for high exposure versus minimal SHTS exposure and were not significant for standard risk factors of diabetes (p = 0.56), hyperlipidemia (p = 0.11), hypertension (p = 0.65), and renal disease (p = 0.24). With increasing SHTS exposure, the percentage of major vessel (14%, 41%, and 45%; p = 0.0013) with any plaque or stenosis increased, as did the number with 5 or more involved segments (0%, 39%, and 61%; p = 0.0001). Also the average number of involved segments increased (0.82, 1.98, and 3.49; p < 0.0001), with calcified plaques alone (0.25, 0.77, and 1.52; p < 0.0001), with calcified and partially calcified plaques (0.28, 0.82, and 1.58; p < 0.001), but not with noncalcified plaques alone (p = 0.11).

CONCLUSIONS

The presence and extent of atherosclerosis were associated with the extent of SHTS exposure even when adjusted for other risk factors, further demonstrating the causal relationship of SHTS exposure and coronary disease.

Tumor volume measurement error using computed tomography imaging in a phase II clinical trial in lung cancer

To address the error introduced by computed tomography (CT) scanners when assessing volume and unidimensional measurement of solid tumors, we scanned a precision manufactured pocket phantom simultaneously with patients enrolled in a lung cancer clinical trial. Dedicated software quantified bias and random error in the [Formula: see text], and [Formula: see text] dimensions of a Teflon sphere and also quantified response evaluation criteria in solid tumors and volume measurements using both constant and adaptive thresholding. We found that underestimation bias was essentially the same for [Formula: see text], and [Formula: see text] dimensions using constant thresholding and had similar values for adaptive thresholding. The random error of these length measurements as measured by the standard deviation and coefficient of variation was 0.10 mm (0.65), 0.11 mm (0.71), and 0.59 mm (3.75) for constant thresholding and 0.08 mm (0.51), 0.09 mm (0.56), and 0.58 mm (3.68) for adaptive thresholding, respectively. For random error, however, [Formula: see text] lengths had at least a fivefold higher standard deviation and coefficient of variation than [Formula: see text] and [Formula: see text]. Observed [Formula: see text]-dimension error was especially high for some 8 and 16 slice CT models. Error in CT image formation, in particular, for models with low numbers of detector rows, may be large enough to be misinterpreted as representing either treatment response or disease progression.

Lung Cancer Deaths in the National Lung Screening Trial Attributed to Nonsolid Nodules

Purpose To validate the recommendation of performing annual follow-up of nonsolid nodules (NSNs) identified by computed tomographic (CT) screening for lung cancer, all cases of lung cancer manifesting as NSN in the National Lung Screening Trial (NLST) were reviewed. Materials and Methods Institutional review board and informed consent were waived for this study. The NLST database was searched to identify all participants with at least one NSN on CT scan with lung cancer as the cause of death (COD) documented by the NLST endpoint verification process. Among the 26 722 participants, 2534 (9.4%) had one or more NSNs, and lung cancer as the COD occurred for 48 participants. On review, 21 of the 48 patients had no NSN in the cancerous lobe, which left 27 patients whose CT scans were reviewed by four radiologists: Group A (n = 12) were cases of lung cancer as the COD because of adenocarcinoma, and group B (n = 15) were cases of lung cancer as the COD because of other cell types. Frequency of lung cancer as the COD because of NSN and the time from randomization to diagnosis within these groups was determined. Results Six of the 12 patients in group A had no NSN in the cancerous lobe whereas the remaining six patients had a dominant solid or part-solid nodule in the lobe that rapidly grew in four patients, was multifocal in one patient, and had a growing NSN in one patient in whom diagnosis was delayed for over 3 years. Five of the 15 patients in group B had no NSN, and for the remaining 10 patients, lung cancer as the COD was not because of NSN. Conclusion It seems unlikely that patients with lung cancer as the COD occurred with solitary or dominant NSN as long as annual follow-up was performed. This lends further support that lung cancers that manifest as NSNs have an indolent course and can be managed with annual follow-up. ^© RSNA, 2016.

Advancing and sharing the knowledge base of CT screening for lung cancer

CT screening for lung cancer is gaining in acceptance and is now moving from the research domain into standard clinical practice. Coincident with this, there is also increasing awareness of the usefulness of collecting large datasets obtained in the clinical domain and how this can be used to advance practice. Toward this end, in the United States, the Centers for Medicare and Medicaid Services (CMS) are requiring data from screening to be entered into certified registries. While this is still in its early stage and only limited datasets are required, this would be particularly relevant if images as well as clinical information were collected as it will allow for additional evaluation of all imaging findings including ancillary ones and understanding how they integrate into the screening process. All of this needs to be considered in the context of how this information can be shared with a person interested in being screened. In particular, the potential benefit of screening needs to be presented in terms of what is meaningful to the individual including their chances of having lung cancer and also their chance of being cured. This is very different then presenting it in terms of mortality reduction which was never meant to be used for that purpose. Also, how findings made on the CT scans, in addition to those related to lung cancer will be meaningful to them.

The importance of the regimen of screening in maximizing the benefit and minimizing the harms

BACKGROUND

In CT screening for lung cancer, the regimen of screening is critical in diagnosing lung cancer early while limiting unnecessary tests and invasive procedures. The International Early Lung Cancer Action Program (I-ELCAP) has developed a regimen based on evidence collected in the I-ELCAP cohort of more than 70,000 participants.

METHODS

Important in the development of the regimen is the recognition of the profound difference between the first, baseline round of screening and all subsequent rounds of repeat screening. For each person undergoing screening, the baseline round happens only once while repeat rounds will be performed annually for many years. This difference needs to be clearly recognized as it is these annual rounds which allow for identification of small, early, yet aggressive, lung cancers which have high cure rates despite their aggressiveness. The importance of nodule consistency and size are key factors in the regimen. The regimen needs to be continuously updated by incorporating advances in technology and knowledge.

RESULTS

The use of the I-ELCAP regimen reduces the workup of participants in the screening program to less than 10% in the baseline round and less than 6% in the annual repeat rounds. By use of this regimen, estimated cure rate of lung cancers diagnosed under screening is 80% or higher in both baseline and annual repeat rounds.

CONCLUSIONS

The I-ELCAP collaboration provides a new paradigm that answers the 2002 NCI call for multiple approaches to address relevant questions about screening and the Institute of Medicine (IOM) Roundtable on Evidence-based Medicine from the National Academy of Science's call for a "new clinical research paradigm that takes better advantage of data generated in the course of healthcare delivery would speed and improve the development of evidence for real-world decision making".

Role of the Quantitative Imaging Biomarker Alliance in optimizing CT for the evaluation of lung cancer screen-detected nodules

The Quantitative Imaging Biomarker Alliance (QIBA) is a multidisciplinary consortium sponsored by the RSNA to define processes that enable the implementation and advancement of quantitative imaging methods described in a QIBA profile document that outlines the process to reliably and accurately measure imaging features. A QIBA profile includes factors such as technical (product-specific) standards, user activities, and relationship to a clinically meaningful metric, such as with nodule measurement in the course of CT screening for lung cancer. In this report, the authors describe how the QIBA approach is being applied to the measurement of small pulmonary nodules such as those found during low-dose CT-based lung cancer screening. All sources of variance with imaging measurement were defined for this process. Through a process of experimentation, literature review, and assembly of expert opinion, the strongest evidence was used to define how to best implement each step in the imaging acquisition and evaluation process. This systematic approach to implementing a quantitative imaging biomarker with standardized specifications for image acquisition and postprocessing for a specific quantitative measurement of a pulmonary nodule results in consistent performance characteristics of the measurement (eg, bias and variance). Implementation of the QIBA small nodule profile may allow more efficient and effective clinical management of the diagnostic workup of individuals found to have suspicious pulmonary nodules in the course of lung cancer screening evaluation.