Low-Grade Appendiceal Mucinous Neoplasm Adhered to the Posterior Cecum: A Case Report.

Low-grade appendiceal mucinous neoplasms (LAMN) constitute a rare subset of epithelial tumors and represent the second most common form of appendiceal cancer. LAMN typically presents as acute appendicitis, with definitive diagnosis often occurring incidentally during appendectomy surgery. While contrast-enhanced computed tomography (CECT) is the imaging of choice, misdiagnoses are common, highlighting the need for additional diagnostic modalities that are often underutilized. There is ongoing debate about treatment recommendations which typically involve a simple appendectomy, but controversy persists regarding the intraoperative necessity of a cecectomy, ileocecectomy, or formal right hemicolectomy. Here, we present a case featuring a 72-year-old African American female referred to our surgery clinic presenting solely with bloating and constipation rather than classical acute appendicitis, discrepancies between CT and MR imaging, and an unusual intraoperative finding of a posteriorly positioned mucocele adhered to the cecum, necessitating right hemicolectomy.

A 20-year Follow-up of the International Early Lung Cancer Action Program (I-ELCAP).

Background The low-dose CT (≤3 mGy) screening report of 1000 Early Lung Cancer Action Program (ELCAP) participants in 1999 led to the International ELCAP (I-ELCAP) collaboration, which enrolled 31 567 participants in annual low-dose CT screening between 1992 and 2005. In 2006, I-ELCAP investigators reported the 10-year lung cancer-specific survival of 80% for 484 participants diagnosed with a first primary lung cancer through annual screening, with a high frequency of clinical stage I lung cancer (85%). Purpose To update the cure rate by determining the 20-year lung cancer-specific survival of participants diagnosed with first primary lung cancer through annual low-dose CT screening in the expanded I-ELCAP cohort. Materials and Methods For participants enrolled in the HIPAA-compliant prospective I-ELCAP cohort between 1992 and 2022 and observed until December 30, 2022, Kaplan-Meier survival analysis was used to determine the 10- and 20-year lung cancer-specific survival of participants diagnosed with first primary lung cancer through annual low-dose CT screening. Eligible participants were aged at least 40 years and had current or former cigarette use or had never smoked but had been exposed to secondhand tobacco smoke. Results Among 89 404 I-ELCAP participants, 1257 (1.4%) were diagnosed with a first primary lung cancer (684 male, 573 female; median age, 66 years; IQR, 61-72), with a median smoking history of 43.0 pack-years (IQR, 29.0-60.0). Median follow-up duration was 105 months (IQR, 41-182). The frequency of clinical stage I at pretreatment CT was 81% (1017 of 1257). The 10-year lung cancer-specific survival of 1257 participants was 81% (95% CI: 79, 84) and the 20-year lung cancer-specific survival was 81% (95% CI: 78, 83), and it was 95% (95% CI: 91, 98) for 181 participants with pathologic T1aN0M0 lung cancer. Conclusion The 10-year lung cancer-specific survival of 80% reported in 2006 for I-ELCAP participants enrolled in annual low-dose CT screening and diagnosed with a first primary lung cancer has persisted, as shown by the updated 20-year lung cancer-specific survival for the expanded I-ELCAP cohort. © RSNA, 2023 See also the editorials by Grenier and by Sequist and Olazagasti in this issue.

The value of education to health: Evidence from Ireland.

Does education have a causal impact on health? The existing literature presents mixed results. More evidence is required from contexts that have not been explored in the literature, and using clinically-measured health outcomes. Using data from the Irish Longitudinal Study on Ageing (TILDA), and exploiting a policy change in the 1960s that eliminated public secondary school fees, we investigate whether additional years of schooling for those with lower socio-economic status (SES) have a causal effect on the prevalence of cardiovascular disease in later life. We find significant sizable effects of education on the prevalence of both hypertension and diabetes. An additional year of schooling decreases the probability of having hypertension by approximately 3% points, and decreases the probability of having diabetes by approximately 1% point, effects that are large given existing prevalence. Further analysis of possible mechanisms shows that additional schooling increases the probability of engaging in high levels of physical activity and refraining from smoking. In the context of an increasing focus on strategies to prevent chronic disease, evidence such as this provides important insights for policymakers tasked with designing public health interventions targeting risk factors for chronic disease.

Computed Tomography Screening for Lung Cancer: Mediastinal Lymph Node Resection in Stage IA Nonsmall Cell Lung Cancer Manifesting as Subsolid and Solid Nodules.

OBJECTIVE: To compare long-term survival rates of patients with first, primary, clinical stage IA nonsmall cell lung cancer from a large cohort undergoing computed tomography screening with and without mediastinal lymph node resection (MLNR) under an Institutional Review Board-approved common protocol from 1992 to 2014. BACKGROUND: Assessing survival differences of patients with and without MLNR manifesting as solid and subsolid nodules. METHODS: Long-term Kaplan-Meier (K-M) survival rates for those with and without MLNR were compared and Cox regression analyses were used to adjust for demographic, computed tomography, and surgical covariates. RESULTS: The long-term K-M rates for 462 with and 145 without MLNR was 92% versus 96% (P = 0.19), respectively. For 203 patients with a subsolid nodule, 151 with and 52 without MLNR, the rate was 100%. For the 404 patients with a solid nodule, 311 with and 93 without MLNR, the rate was 87% versus 94% (P = 0.24) and Cox regression showed no statistically significant difference (P = 0.28) when adjusted for all covariates. Risk of dying increased significantly with increasing decades of age (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.4-3.8), centrally located tumor (HR 2.5, 95% CI 1.2-5.2), tumor size 21 to 30 mm (HR 2.7, 95% CI 1.2-6.0), and invasion beyond the lung stroma (HR 3.0, 95% CI 1.4-6.1). For the 346 patients with MLNR, tumor size was 20 mm or less; K-M rates for the 269 patients with and 169 patients without MLNR were also not significantly different (HR 2.1, P = 0.24). CONCLUSIONS: It is not mandatory to perform MLNR when screen-diagnosed nonsmall cell lung cancer manifests as a subsolid nodule.

CT Screening for Lung Cancer: Part-Solid Nodules in Baseline and Annual Repeat Rounds.

OBJECTIVE: The purpose of this study was to assess the frequencies of identifying participants with part-solid nodules, of diagnostic pursuit, of diagnoses of lung cancer, and long-term lung cancer survival in baseline and annual repeat rounds of CT screening in the International Early Lung Cancer Action Project. MATERIALS AND METHODS: Screenings were performed under a common protocol. Participants with solid, nonsolid, and part-solid nodules and the diagnoses of lung cancer were documented. RESULTS: Part-solid nodules were identified in 2892 of 57,496 (5.0%) baseline screening studies; 567 (19.6%) of these nodules resolved or decreased in size. Diagnostic pursuit led to the diagnosis of adenocarcinoma in 79 cases, all clinical stage I. At resection, one nodule (12-mm solid component) had a single N2 metastasis. A new part-solid nodule was identified in 541 of 64,677 (0.8%) annual repeat screenings; 377 (69.7%) of these nodules resolved or decreased in size. In eight cases among the 541, the diagnosis of adenocarcinoma manifesting as a part solid nodule was made; on retrospective review the nodule originally had been a nonsolid nodule. In another 20 cases, the cancer originally had manifested as a nonsolid nodule but had progressed to become part-solid at annual repeat screening before any diagnosis was pursued. These 28 annual repeat cases of lung cancer were all pathologic stage IA. Of the 107 cases of lung cancer (79 baseline cases and 28 annual repeat cases), 106 were surgically resected, and one baseline case was followed up with imaging for 4 years. The lung cancer survival rate was 100% with a median follow-up period from diagnosis of 89 months (interquartile range, 52-134 months). CONCLUSION: Lung cancers manifesting as part-solid nodules at repeat screening studies all started as nonsolid nodules. Among 107 cases of adenocarcinoma manifesting as a part-solid nodule, a single lymph node metastasis was found in a single case (solid component, 12 mm).

CT Screening for Lung Cancer: Nonsolid Nodules in Baseline and Annual Repeat Rounds.

PURPOSE: To address the frequency of identifying nonsolid nodules, diagnosing lung cancer manifesting as such nodules, and the long-term outcome after treatment in a prospective cohort, the International Early Lung Cancer Action Program. MATERIALS AND METHODS: A total of 57,496 participants underwent baseline and subsequent annual repeat computed tomographic (CT) screenings according to an institutional review board, HIPAA-compliant protocol. Informed consent was obtained. The frequency of participants with nonsolid nodules, the course of the nodule at follow-up, and the resulting diagnoses of lung cancer, treatment, and outcome are given separately for baseline and annual repeat rounds of screening. The χ(2) statistic was used to compare percentages. RESULTS: A nonsolid nodule was identified in 2392 (4.2%) of 57,496 baseline screenings, and pathologic pursuit led to the diagnosis of 73 cases of adenocarcinoma. A new nonsolid nodule was identified in 485 (0.7%) of 64,677 annual repeat screenings, and 11 had a diagnosis of stage I adenocarcinoma; none were in nodules 15 mm or larger in diameter. Nonsolid nodules resolved or decreased more frequently in annual repeat than in baseline rounds (322 [66%] of 485 vs 628 [26%] of 2392, P < .0001). Treatment of the cases of lung cancer was with lobectomy in 55, bilobectomy in two, sublobar resection in 26, and radiation therapy in one. Median time to treatment was 19 months (interquartile range [IQR], 6-41 months). A solid component had developed in 22 cases prior to treatment (median transition time from nonsolid to part-solid, 25 months). The lung cancer-survival rate was 100% with median follow-up since diagnosis of 78 months (IQR, 45-122 months). CONCLUSION: Nonsolid nodules of any size can be safely followed with CT at 12-month intervals to assess transition to part-solid. Surgery was 100% curative in all cases, regardless of the time to treatment.

Enhancing sensitivity and specificity in rare cell capture microdevices with dielectrophoresis.

The capture and subsequent analysis of rare cells, such as circulating tumor cells from a peripheral blood sample, has the potential to advance our understanding and treatment of a wide range of diseases. There is a particular need for high purity (i.e., high specificity) techniques to isolate these cells, reducing the time and cost required for single-cell genetic analyses by decreasing the number of contaminating cells analyzed. Previous work has shown that antibody-based immunocapture can be combined with dielectrophoresis (DEP) to differentially isolate cancer cells from leukocytes in a characterization device. Here, we build on that work by developing numerical simulations that identify microfluidic obstacle array geometries where DEP-immunocapture can be used to maximize the capture of target rare cells, while minimizing the capture of contaminating cells. We consider geometries with electrodes offset from the array and parallel to the fluid flow, maximizing the magnitude of the resulting electric field at the obstacles' leading and trailing edges, and minimizing it at the obstacles' shoulders. This configuration attracts cells with a positive DEP (pDEP) response to the leading edge, where the shear stress is low and residence time is long, resulting in a high capture probability; although these cells are also repelled from the shoulder region, the high local fluid velocity at the shoulder minimizes the impact on the overall transport and capture. Likewise, cells undergoing negative DEP (nDEP) are repelled from regions of high capture probability and attracted to regions where capture is unlikely. These simulations predict that DEP can be used to reduce the probability of capturing contaminating peripheral blood mononuclear cells (using nDEP) from 0.16 to 0.01 while simultaneously increasing the capture of several pancreatic cancer cell lines from 0.03-0.10 to 0.14-0.55, laying the groundwork for the experimental study of hybrid DEP-immunocapture obstacle array microdevices.

The impact of the regimen of screening on lung cancer cure: a comparison of I-ELCAP and NLST.

The aim of this study was to assess the impact of the regimen of screening on the frequency of early diagnosis and resection in two computed tomography screening programs. The stage and size distribution of all screen-diagnosed lung cancers was compared. A total of 775 patients in the International Early Lung Cancer Action Program (I-ELCAP) and 664 patients in the National Lung Screening Trial (NLST) were screen-diagnosed; that is, resulting from a positive result requiring further diagnostic workup. The frequency of stage I diagnoses, resections, tumor size, and lung cancer-specific survival were determined. Cox regression was used to identify the key determinants of lung cancer cure. The frequency of clinical stage I lung cancer in I-ELCAP was 82%, and in the NLST it was 67% (P<0.0001). The frequency of stage I (pathologic and clinical if not resected) was 78% in I-ELCAP and 62% in the NLST (P<0.0001). Surgical resection was performed in 86% (664/755) in I-ELCAP and 76% (492/644, P<0.0001) in the NLST. The average tumor size was 17 mm in I-ELCAP and 23 mm in the NLST (P<0.0001). The 5-year survival rate was 83% in I-ELCAP and 62% in the NLST (P<0.0001). Cox regression showed that I-ELCAP provided a 50% better survival benefit than the NLST and that stage I and resection were key determinants of survival, independent of age, smoking history, and tumor size. The higher frequency of stage I disease and resection and smaller tumor size resulted in a significantly higher survival rate in I-ELCAP than in the NLST. These differences strongly support the importance of a specified regimen of screening, as alternative explanations have been addressed.

Characterization of microfluidic shear-dependent epithelial cell adhesion molecule immunocapture and enrichment of pancreatic cancer cells from blood cells with dielectrophoresis.

Current microfluidic techniques for isolating circulating tumor cells (CTCs) from cancer patient blood are limited by low capture purity, and dielectrophoresis (DEP) has the potential to complement existing immunocapture techniques to improve capture performance. We present a hybrid DEP and immunocapture Hele-Shaw flow cell to characterize DEP's effects on immunocapture of pancreatic cancer cells (Capan-1, PANC-1, and BxPC-3) and peripheral blood mononuclear cells (PBMCs) with an anti-EpCAM (epithelial cell adhesion molecule) antibody. By carefully specifying the applied electric field frequency, we demonstrate that pancreatic cancer cells are attracted to immunocapture surfaces by positive DEP whereas PBMCs are repelled by negative DEP. Using an exponential capture model to interpret our capture data, we show that immunocapture performance is dependent on the applied DEP force sign and magnitude, cell surface EpCAM expression level, and shear stress experienced by cells flowing in the capture device. Our work suggests that DEP can not only repel contaminating blood cells but also enhance capture of cancer cell populations that are less likely to be captured by traditional immunocapture methods. This combination of DEP and immunocapture techniques to potentially increase CTC capture purity can facilitate subsequent biological analyses of captured CTCs and research on cancer metastasis and drug therapies.

Retrospective review of lung cancers diagnosed in annual rounds of CT screening.

OBJECTIVE: The purpose of this study was to review the records of patients with diagnoses of lung cancer in annual repeat rounds of CT screening in the International Early Lung Cancer Action Program to determine whether the cancer could have been identified in the previous round of screening. MATERIALS AND METHODS: Three radiologists reviewed the scans of 104 lung cancer patients and assigned the findings to one of three categories: 1, cancer was not visible at previous CT screening; 2, cancer was visible at previous CT screening but not identified; 3, abnormality was identified at previous CT screening but not classified as malignant. Nodule size, nodule consistency, cell type, and stage at the previous screening and when identified for further workup for each of the three categories were tabulated. RESULTS: Twenty-four (23%) patients had category 1 findings; 56 (54%) category 2; and 24 (23%) category 3. When diagnosed, seven (29%) category 1, 10 (18%) category 2, and four (17%) category three cancers had progressed beyond stage I. All cancers seen in retrospect were in clinical stage I at the previous screening. Category 1 cancers, compared with categories 2 and 3, had faster growth rates, were less frequently adenocarcinomas (29% vs 54% and 67%, p = 0.01), and were more often small cell carcinomas (29% vs 14% and 12%, p = 0.12). CONCLUSION: Lung cancers found on annual repeat screenings were frequently identified in the previous round of screening, suggesting that review of the varied appearance and incorporation of advanced image display may be useful for earlier detection.

CT screening for lung cancer: alternative definitions of positive test result based on the national lung screening trial and international early lung cancer action program databases.

PURPOSE: To determine the usefulness of alternative nodule size thresholds in a population undergoing computed tomographic (CT) screening for lung cancer and to compare the reported International Early Lung Cancer Action Program ( I-ELCAP International Early Lung Cancer Action Program ) results with the National Lung Screening Trial ( NLST National Lung Screening Trial ) results. MATERIALS AND METHODS: The institutional review board approved this retrospective analysis. Informed consent was obtained according to HIPAA compliance. Findings in the CT cohort in the NLST National Lung Screening Trial of 25 813 participants who underwent baseline CT in 2002-2004 were reviewed. The frequency of solid and part-solid pulmonary nodules and the lung cancer diagnoses using an alternative nodule threshold of 5.0, 6.0, 7.0, 8.0, and 9.0 mm were determined. Proportional reduction in the frequency of positive results and their 95% confidence intervals using each of the alternative thresholds were calculated. RESULTS: The frequency of positive results in the baseline round in the CT arm of the NLST National Lung Screening Trial using the definition of a positive result of any parenchymal, solid or part-solid, noncalcified nodule of 5.0 mm or larger was 15.8% (4080 of 25 813). Using alternative thresholds of 6.0, 7.0, 8.0, and 9.0 mm, the frequencies of positive results were 10.5% (2700 of 25 813, 7.2% (1847 of 25 813), 5.3% (1362 of 25 813), and 4.1% (1007 of 25 813), respectively, and the corresponding proportional reduction in additional CT scans would have been 33.8% (1380 of 1480), 54.7% (2233 of 4080), 66.6% (2718 of 4080), and 73.8% (3013 of 4080), respectively. Concomitantly, the proportion of lung cancer diagnoses determined within the first 12 months would be delayed up to 9 months for 0.9% (two of 232), 2.6% (six of 232), 6.0% (14 of 232), and 9.9% (23 of 232) of the patients, respectively. CONCLUSION: The NLST National Lung Screening Trial results are similar to those previously reported for the I-ELCAP International Early Lung Cancer Action Program and suggest that, even for high-risk participants in the NLST National Lung Screening Trial , higher thresholds of nodule size should be considered and prospectively evaluated.

Balancing curability and unnecessary surgery in the context of computed tomography screening for lung cancer.

OBJECTIVE: Surgical management is a critical component of computed tomography (CT) screening for lung cancer. We report the results for US sites in a large ongoing screening program, the International Early Lung Cancer Action Program (I-ELCAP). METHODS: We identified all patients who underwent surgical resection. We compared the results before (1993-2005) and after (2006-2011) termination of the National Lung Screening Trial to identify emerging trends. RESULTS: Among 31,646 baseline and 37,861 annual repeat CT screenings, 492 patients underwent surgical resection; 437 (89%) were diagnosed with lung cancer; 396 (91%) had clinical stage I disease. In the 54 (11%) patients with nonmalignant disease, resection was sublobar in 48 and lobectomy in 6. The estimated cure rate based on the 15-year Kaplan-Meier survival for all 428 patients (excluding 9 typical carcinoids) with lung cancer was 84% (95% confidence interval [CI], 80%-88%) and 88% (95% CI, 83%-92%) for clinical stage I disease resected within 1 month of diagnosis. Video-assisted thoracoscopic surgery and sublobar resection increased significantly, from 10% to 34% (P < .0001) and 22% to 34% (P = .01) respectively; there were no significant differences in the percentage of malignant diagnoses (90% vs 87%, P = .36), clinical stage I (92% vs 89%, P = .33), pathologic stage I (85% vs 82%, P = .44), tumor size (P = .61), or cell type (P = .81). CONCLUSIONS: The frequency and extent of surgery for nonmalignant disease can be minimized in a CT screening program and provide a high cure rate for those diagnosed with lung cancer and undergoing surgical resection.

Parametric control of collision rates and capture rates in geometrically enhanced differential immunocapture (GEDI) microfluidic devices for rare cell capture.

The enrichment and isolation of rare cells from complex samples, such as circulating tumor cells (CTCs) from whole blood, is an important engineering problem with widespread clinical applications. One approach uses a microfluidic obstacle array with an antibody surface functionalization to both guide cells into contact with the capture surface and to facilitate adhesion; geometrically enhanced differential immunocapture is a design strategy in which the array is designed to promote target cell­obstacle contact and minimize other interactions (Gleghorn et al. 2010; Kirby et al. 2012). We present a simulation that uses capture experiments in a simple Hele-Shaw geometry (Santana et al. 2012) to inform a target-cell-specific capture model that can predict capture probability in immunocapture microdevices of any arbitrary complex geometry. We show that capture performance is strongly dependent on the array geometry, and that it is possible to select an obstacle array geometry that maximizes capture efficiency (by creating combinations of frequent target cell­obstacle collisions and shear stress low enough to support capture), while simultaneously enhancing purity by minimizing nonspecific adhesion of both smaller contaminant cells (with infrequent cell­obstacle collisions) and larger contaminant cells (by focusing those collisions into regions of high shear stress).

Healthy Aging in China.

China has aged rapidly and the rate is accelerating in decades to come. We review positive and negative forces for healthy aging in China now and in the future. The most positive force is the spectacular growth in education over time especially for Chinese women, which should improve all dimensions of cognitive and physical health and eliminate vast gender disparities in healthy aging that currently exist. Other positive forces include increasing detection and treatment of disease and the availability of health insurance and health services so that diseases like hypertension and diabetes do not remain silent killers in China. Transparency is eased on the research level by publicly available data such as CHARLS, a sharp departure from prior scientific norm in China. Negative forces center on disturbing trends in personal health behaviors such as growing rates of smoking (among men) and obesity (for both genders), and pollution-,especially in urban centers. Public health campaigns and incentives are needed on all these fronts so that predictable long-term consequences of these behaviors on older age disease are not realized. There will not be a simple demographic fix to healthy aging in China as fertility rates are unlikely to rise much, while migration will likely continue to rise leaving growing numbers of elderly parents geographically separated from their adult children. Government policy will have to allow migration of elderly parents to live with their adult children while reducing the rigid connection of policy (health insurance and health services) with place of residence.

Definition of a positive test result in computed tomography screening for lung cancer: a cohort study.

BACKGROUND: Low-dose computed tomography screening for lung cancer can reduce mortality among high-risk persons, but "false-positive" findings may result in unnecessary evaluations with attendant risks. The effect of alternative thresholds for defining a positive result on the rates of positive results and cancer diagnoses is unknown. OBJECTIVE: To assess the frequency of positive results and potential delays in diagnosis in the baseline round of screening by using more restrictive thresholds. DESIGN: Prospective cohort study. SETTING: Multi-institutional International Early Lung Cancer Action Program. PATIENTS: 21 136 participants with baseline computed tomography performed between 2006 and 2010. MEASUREMENTS: The frequency of solid and part-solid pulmonary nodules and the rate of lung cancer diagnosis by using current (5 mm) and more restrictive thresholds of nodule diameter. RESULTS: The frequency of positive results in the baseline round by using the current definition of positive result (any parenchymal, solid or part-solid, noncalcified nodule ≥5.0 mm) was 16% (3396/21 136). When alternative threshold values of 6.0, 7.0, 8.0 and 9.0 mm were used, the frequencies of positive results were 10.2% (95% CI, 9.8% to 10.6%), 7.1% (CI, 6.7% to 7.4%), 5.1% (CI, 4.8% to 5.4%), and 4.0% (CI, 3.7% to 4.2%), respectively. Use of these alternative definitions would have reduced the work-up by 36%, 56%, 68%, and 75%, respectively. Concomitantly, lung cancer diagnostics would have been delayed by at most 9 months for 0%, 5.0% (CI, 1.1% to 9.0%), 5.9% (CI, 1.7 to 10.1%), and 6.7% (CI, 2.2% to 11.2%) of the cases of cancer, respectively. LIMITATION: This was a retrospective analysis and thus whether delays in diagnosis would have altered outcomes cannot be determined. CONCLUSION: These findings suggest that using a threshold of 7 or 8 mm to define positive results in the baseline round of computed tomography screening for lung cancer should be prospectively evaluated to determine whether the benefits of decreasing further work-up outweigh the consequent delay in diagnosis in some patients.

Lung cancer associated with cystic airspaces.

OBJECTIVE: The objectives of this study were to determine the frequency of lung cancers associated with a discrete cystic airspace and to characterize the morphologic and pathologic features of the cancer and the cystic airspace. MATERIALS AND METHODS: We reviewed all diagnosed cases of lung cancer resulting from baseline screening (n=595) and annual screening (n=111) in the International Early Lung Cancer Action Program to identify those abutting or in the wall of a cystic airspace. We also reviewed the pathologic specimens. RESULTS: A total of 26 lung cancers were identified abutting or in the wall of a cystic airspace. Of these, 13 were identified at baseline (13/595, 2%) and 13 at annual screening (13/111, 12%), which was significant (p<0.0001). The median circumferential portion of wall involved was less for the annual cancers than for the baseline ones, but this difference did not reach significance (90° vs 240°, p=0.07). The diagnosis was adenocarcinoma in all but three cases. Histologic analysis showed that the cystic space was a bulla, a fibrous walled cyst without a defined lining, or a pleural bleb and that in all but one case, the tumor was eccentric relative to the airspace and the wall of the airspace was unevenly thickened. CONCLUSION: At annual repeat CT screening, the finding of an isolated cystic airspace with increased wall thickness should raise the suspicion of lung cancer.

Radiographic and clinical characterization of false negative results from CT-guided needle biopsies of lung nodules.

INTRODUCTION: Computed tomography-guided transthoracic fine-needle aspiration (FNA) is a highly sensitive technique for diagnosing malignancy in pulmonary nodules; however, there is great uncertainty regarding the reliability of a benign result. The goal of this study was to characterize the clinical, radiologic, and technical variables associated with a false negative result. METHODS: We performed a consecutive series review of patients who had an initial benign result from an FNA between January 2002 and December 2004. Medical charts were reviewed to identify patients with false negative and true negative results and determine which variables were associated with a missed diagnosis. RESULTS: One hundred and seventy patients underwent an FNA biopsy yielding an initial benign result and had adequate clinical follow-up. Eighteen of these proved to be false negatives and 152 were true negative. Compared with the patients with true negatives, those with false negative results had significantly larger nodules (mean, 27 mm versus 17 mm, p = 0.04), fewer imaging adjustments per needle pass (4.5 versus 6.4, p = 0.01), a higher proportion in whom the needle tip was not documented within the lesion (24% versus 5%, p =0.04), and a higher pneumothorax rate at any point during the procedure (50% versus 22%, p =0.04). When these variables were considered jointly, pneumothorax (p = 0.006), solitary nodule (p = 0.04), and the radiologist who performed the procedure (p = 0.04) were significant predictors of false negative results. CONCLUSIONS: Factors that were associated with false negative results include increased size of lesion, fewer adjustments of the needle, lack of positive cultures, and the occurrence of a pneumothorax. A benign FNA biopsy result should have the procedure reviewed to ensure the results are reliable.