Peripheral lung adenocarcinoma: correlation of thin-section CT findings with histologic prognostic factors and survival

Thin-section computed tomography findings of lung adenocarcinoma with inherent metastatic potential

PURPOSE

The solid component of lung ground-glass nodules on thin-section computed tomography (TSCT) reflects cancer cell progression and invasiveness. The purpose of this study was to clarify the cut-off value of preoperative TSCT findings in treating a lesion suspected of being adenocarcinoma and to recognize the timing of surgical resection for lung nodules.

METHODS

We reevaluated the TSCT findings in 392 patients with clinical stage IA lung adenocarcinoma who underwent surgical resection between 2003 and 2007. We identified the clinical parameters that were most useful for predicting recurrence and identified a cut-off level for each parameter.

RESULTS

Recurrence was observed in 75 (19 %) of 392 patients (median follow-up: 7 years). The size of internal consolidation of a lung nodule (SCL) and the ratio of the SCL to the maximum tumor diameter (C/T ratio) were extracted as independent factors that predicted recurrence. Only 1 (0.3 %) patient each with a lung nodule C/T ratio ≤0.5 and SCL ≤10 mm recurred. These conditions were associated with a significantly better overall survival and recurrence-free survival.

CONCLUSION

In patients with clinical stage I lung adenocarcinoma with a C/T ratio ≤0.5 and/or SCL ≤10 mm on TSCT, surgery is extremely likely to achieve a cure.

Lung adenocarcinomas: correlation of computed tomography and pathology findings

Adenocarcinoma is the most common histologic type of lung cancer. Recent lung adenocarcinoma classifications from the International Association for the Study of Lung cancer, the American Thoracic Society and the European Respiratory Society (IASLC/ETS/ERS, 2011) and World Health Organization (WHO, 2015) define a wide range of adenocarcinoma types and subtypes featuring different prognosis and management. This spectrum of lesions translates into various CT presentations and features, which generally show good correlation with histopathology, stressing the key role of the radiologist in the diagnosis and management of those patients. This review aims at helping radiologists to understand the basics of the up-to-date adenocarcinoma pathological classifications, radio-pathological correlations and how to use them in the clinical setting, as well as other imaging-related correlations (radiogenomics, quantitative analysis, PET-CT).

Imaging Heterogeneity in Lung Cancer: Techniques, Applications, and Challenges

OBJECTIVE

Texture analysis involves the mathematic processing of medical images to derive sets of numeric quantities that measure heterogeneity. Studies on lung cancer have shown that texture analysis may have a role in characterizing tumors and predicting patient outcome. This article outlines the mathematic basis of and the most recent literature on texture analysis in lung cancer imaging. We also describe the challenges facing the clinical implementation of texture analysis.

CONCLUSION

Texture analysis of lung cancer images has been applied successfully to FDG PET and CT scans. Different texture parameters have been shown to be predictive of the nature of disease and of patient outcome. In general, it appears that more heterogeneous tumors on imaging tend to be more aggressive and to be associated with poorer outcomes and that tumor heterogeneity on imaging decreases with treatment. Despite these promising results, there is a large variation in the reported data and strengths of association.

Quantitative Computed Tomography Imaging Biomarkers in the Diagnosis and Management of Lung Cancer

Tumor diameter has traditionally been used as a standard metric in terms of diagnosis and prognosis prediction of lung cancer. However, recent advances in imaging techniques and data analyses have enabled novel quantitative imaging biomarkers that can characterize disease status more comprehensively and/or predict tumor behavior more precisely. The most widely used imaging modality for lung tumor assessment is computed tomography. Therefore, we focused on computed tomography imaging biomarkers such as tumor volume and mass, ground-glass opacities, perfusion parameters, as well as texture features in this review. Herein, we first appraised the conventional 1- or 2-dimensional measurement with brief discussion on their limits and then introduced the potential imaging biomarkers with emphasis on the current understanding of their clinical usefulness with respect to the malignancy differentiation, treatment response monitoring, and patient outcome prediction.

Microscopic Invasions, Prognoses, and Recurrence Patterns of Stage I Adenocarcinomas Manifesting as Part-Solid Ground-Glass Nodules: Comparison With Adenocarcinomas Appearing as Solid Nodules After Matching Their Solid Parts' Size

The purpose of the present study was to compare the frequency of microscopic invasions, disease-free-survival (DFS), and the frequency and pattern of disease recurrence between stage I pulmonary adenocarcinomas appearing as solid nodules and those appearing as part-solid ground-glass nodules (GGNs) after matching their solid parts' size (D(solid)) and patients' age. Among 501 patients who underwent curative surgery for stage I pulmonary adenocarcinomas between 2003 and 2011, 172 patients (86 with solid nodules [M: F = 36: 50; mean age, 62.8 years] and 86 with part-solid GGNs [M:F = 30:56; mean age, 63.0 years]) matched for D(solid) and patients' age were included. DFS, frequency of microscopic invasions, recurrence, and recurrence pattern were compared between the two groups. No significant difference was observed in the frequency of microscopic invasions between the two groups (visceral pleural invasion, 30.23% vs. 29.07%, P = 0.867; lymphatic invasion, 5.81% vs. 3.49%, P = 0.720; vascular invasion, 1.16% vs. 0%, P = 1.000; solid nodules vs. part-slid GGNs, respectively) and DFS (estimated 5-year DFS, 83.6% vs. 81.9%, P = 0.744; solid nodules vs. part-slid GGNs, respectively). As for recurrence and recurrence pattern, there were no significant differences between the solid nodule group (14/86), and part-solid GGN group (12/86) (P = 0.670). Lung parenchymal nodules were the most frequent pattern of disease recurrence in both groups, followed by pleural seeding. In conclusion, after matching D(solid) and patients' age, there was no significant difference in the frequency of microscopic invasions, DFS, and the frequency and pattern of recurrence between stage I pulmonary adenocarcinomas appearing as solid nodules and part-solid GGNs.

Improvement in imaging diagnosis technique and modalities for solitary pulmonary nodules: from ground-glass opacity nodules to part-solid and solid nodules

With advances in CT technology and the popularity of low-dose CT as a device for lung cancer screening, the detection rate of sub-solid pulmonary nodules as well as solid nodules has been increased. Distinguishing solid from sub-solid features is an essential step in the CT evaluation of solitary pulmonary nodules (SPNs) because strategies for nodule characterization and guidelines for management are different for each category. In addition to conventional CT parameters, numerous novel concepts and modalities have been developed. Although there is currently no single effective method for differentiating malignant from benign nodules, growth rate measurement using volumetry, evaluation of tumor vascularity on dynamic helical CT, dual-energy CT and MRI and physiologic evaluation with PET/CT can all be useful for nodule characterization. New techniques such as tomosynthesis can improve detection over radiography alone. The purpose of this article is to enhance our understanding of the evidence-based strategies involved in diagnosing SPNs.

Long-Term Follow-Up Results From PET/CT Surveillance After Surgical Resection of Lung Adenocarcinoma Manifesting as Ground-Glass Opacity

The purpose of our study was to retrospectively evaluate the value of F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for postoperative surveillance of lung adenocarcinoma manifesting as ground-glass opacity (GGO).From May 2003 to December 2007, 111 patients with surgically resected lung adenocarcinoma manifesting as GGO were included. Clinical findings of recurrence and survival, CT features, and maximum standardized uptake value (SUVmax) were reviewed and compared among 3 groups according to GGO proportion: Group I, GGO 100%; Group II, GGO ≥50%; Group III, GGO < 50%. Disease-free survival (DFS) was estimated using the Kaplan-Meier method. Diagnostic performances of CT and PET/CT for recurrence were compared during a long-term follow-up period of >5 years.Recurrence was identified in Group III (18 of 53, 34%) but not in Groups I (n = 25) or II (n = 33) over a mean follow-up period of 74 months. Group showed significant differences in GGO proportion, SUVmax, and DFS duration (P < 0.001). PET/CT led to 6 false-positive and 5 false-negative interpretations of recurrence. For surveillance CT, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 94.4%, 98.6%, 98.2%, 94.4%, and 98.9%, respectively; for PET/CT, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 72.2%, 92.3%, 88.5%, 68.4%, and 93.5%, respectively. CT showed significantly higher accuracy than PET/CT (P = 0.0188).FDG-PET/CT showed no clear advantage for postoperative surveillance of lung cancer with predominant GGO because of low incidence of recurrence and frequent false-positive and false-negative results.

Association Between Computed Tomographic Features and Kirsten Rat Sarcoma Viral Oncogene Mutations in Patients With Stage I Lung Adenocarcinoma and Their Prognostic Value

BACKGROUND

We investigated the association between computed tomographic (CT) features and Kirsten rat sarcoma viral oncogene (KRAS) mutations in patients with stage I lung adenocarcinoma and their prognostic value.

PATIENTS AND METHODS

A total of 79 patients with pathologic stage I lung adenocarcinoma, available KRAS mutational status, preoperative CT images available, and survival data were included in the present study. Seven CT features, including spiculation, concavity, ground-glass opacity, bubble-like lucency, air bronchogram, pleural retraction, and pleural attachment, were evaluated. The association among the clinical characteristics, CT features, and mutational status was analyzed using Student's t test, the χ(2) test or Fisher's exact test, and logistic regression. The association among CT features, mutational status, and overall survival was analyzed using Kaplan-Meier survival curves with the log-rank test and Cox proportional hazard regression.

RESULTS

The prevalence of KRAS mutations was 41.77%. Spiculation was significantly associated with the presence of KRAS mutations (odds ratio, 2.99; 95% confidence interval [CI], 1.16-7.68). Although KRAS mutational status was not significantly associated with overall survival, the presence of pleural attachment was associated with an increased risk of death (hazard ratio, 2.46; 95% CI, 1.09-5.53). When analyzing KRAS mutational status and pleural attachment combined, patients with wild-type KRAS and no pleural attachment had significantly better survival than did those with wild-type KRAS and pleural attachment (P = .014).

CONCLUSION

These data suggest that spiculation is associated with KRAS mutations and pleural attachment is associated with overall survival in patients with stage I lung adenocarcinoma. Combining the analysis of KRAS mutational status and CT features could better predict survival.

Growth of pure ground-glass lung nodule detected at computed tomography

The natural history of pure ground-glass nodules (GGNs) of the lung has been gradually revealed. Approximately 10-25% of pure GGNs increases in size or grow the solid component, while others remain unchanged for years. Further investigations including the relationship between the successive change on computed tomography (CT) and the molecular change may be necessary to determine the appropriate management strategy of pure GGNs.

Correlation between whole tumor size and solid component size on high-resolution computed tomography in the prediction of the degree of pathologic malignancy and the prognostic outcome in primary lung adenocarcinoma

BACKGROUND

The presence of ground glass opacity (GGO) on high-resolution computed tomography (HRCT) is well known to be pathologically closely associated with adenocarcinoma in situ.

PURPOSE

To determine whether it is more useful to evaluate the whole tumor size or only the solid component size to predict the pathologic high-grade malignancy and the prognostic outcome in lung adenocarcinoma.

MATERIAL AND METHODS

Using HRCT data of 232 patients with adenocarcinoma who underwent curative resection, we retrospectively measured the whole tumor and solid component sizes with lung window setting (WTLW and SCLW) and whole tumor sizes with a mediastinal window setting (WTMW).

RESULTS

There was significant correlation between the WTLW and the measurements of pathological whole tumor (pWT) (r = 0.792, P < 0.0001). The SCLW and WTLW values significantly correlated with the area of pathological invasive component (pIVS) (r = 0.762, P < 0.0001 and r = 0.771, P < 0.0001, respectively). The receiver operating characteristics area under the curve for WTLW, SCLW, and WTMW used to identify lymph node metastasis or lymphatic or vascular invasion were 0.693, 0.817, and 0.824, respectively. Kaplan-Meier curves of disease-free survival (DFS) and overall survival (OS) were better divided according to SCLW and WTMW, compared with WTLW. Multivariate analysis of DFS and OS revealed that WTMW was an independent prognostic factor (HR = 0.72, 95% confidence interval [CI] = 0.58-0.90, P = 0.004 and HR = 0.74, 95% CI = 0.57-0.96, P = 0.022, respectively).

CONCLUSION

The predictive values of the solid tumor size visualized on HRCT especially in the mediastinal window for pathologic high-grade malignancy and prognosis in lung adenocarcinoma were greater than those of whole tumor size.

Persistent pulmonary subsolid nodules with solid portions of 5 mm or smaller: Their natural course and predictors of interval growth

OBJECTIVE

To investigate the natural course of persistent pulmonary subsolid nodules (SSNs) with solid portions ≤5 mm and the clinico-radiological features that influence interval growth over follow-ups.

METHODS

From 2005 to 2013, the natural courses of 213 persistent SSNs in 213 patients were evaluated. To identify significant predictors of interval growth, Kaplan-Meier analysis and Cox proportional hazard regression analysis were performed.

RESULTS

Among the 213 nodules, 136 were pure ground-glass nodules (GGNs; growth, 18; stable, 118) and 77 were part-solid GGNs with solid portions ≤5 mm (growth, 24; stable, 53). For all SSNs, lung cancer history (p = 0.001), part-solid GGNs (p < 0.001), and nodule diameter (p < 0.001) were significant predictors for interval growth. On subgroup analysis, nodule diameter was an independent predictor for the interval growth of both pure GGNs (p < 0.001), and part-solid GGNs (p = 0.037). For part-solid GGNs, lung cancer history (p = 0.002) was another significant predictor of the interval growth. Interval growth of pure GGNs ≥10 mm and part-solid GGNs ≥8 mm were significantly more frequent than in pure GGNs <10 mm (p < 0.001) and part-solid GGNs <8 mm (p = 0.003), respectively.

CONCLUSION

The natural course of SSNs with solid portions ≤5 mm differed significantly according to their nodule type and nodule diameters, with which their management can be subdivided.

KEY POINTS

• Pure GGNs ≥10 mm have significantly more frequent interval growth than those <10 mm. • Part-solid GGNs ≥8 mm have significantly more frequent interval growth than those <8 mm. • Management of SSNs with solid portions ≤5 mm can be subdivided by diameter.

Correlation between FDG-PET/CT findings and solid type non-small cell cancer prognostic factors: are there differences between adenocarcinoma and squamous cell carcinoma?

OBJECTIVES

The maximum standardized uptake value (SUVmax) of FDG-PET/CT is commonly used as an indicator to evaluate the invasiveness and prognosis of non-small-cell lung cancers (NSCLC). We investigated the correlation between SUVmax and tumor invasiveness or postoperative recurrence of solid type NSCLC and compared squamous cell carcinoma (SCC)/adenosquamous carcinoma (ASC) to adenocarcinoma (AC).

METHODS

A retrospective review of preoperative PET/CT, thin-section CT, and postoperative pathological records obtained over a 5-year period was conducted. Solid type NSCLC tumors on thin-section CT with confirmed diagnosis from surgical resection (diameter ≤3 cm) were included. Multivariate logistic regression was used to evaluate the correlation between tumor characteristics and pathological prognostic factors or postoperative recurrence.

RESULTS

150 patients (111 males, 39 females; mean age 67 years; 106 cases of AC, 36 cases of SCC, and 8 cases of ASC) were included. SUVmax was significantly correlated with pleural involvement (p = 0.047), lymphatic permeation (p = 0.003), lymph node metastasis (p = 0.027), and tumor invasiveness (p < 0.001). Receiver operating characteristic analysis indicated an optimal SUVmax threshold of 5.0 for tumor invasiveness. Histopathological type was significantly correlated with pleural involvement (p = 0.042), but not with other types of invasiveness. Twenty-nine patients experienced postoperative recurrence. SUVmax was significantly correlated with tumor recurrence (p = 0.004), but size and histopathological type were not (p = 0.502 and p = 0.351, respectively).

CONCLUSION

SUVmax of the primary lesion in solid type NSCLC was significantly correlated with tumor invasiveness and postoperative recurrence. No differences in tumor invasiveness were observed between solid type AC and SCC/ASC. However, in solid type AC, SUVmax of the primary lesion was more significantly correlated with recurrence.

Limited Resection Versus Lobectomy for Older Patients With Early-Stage Lung Cancer: Impact of Histology

PURPOSE

Limited resection has been increasingly used in older patients with stage IA lung cancer. However, the equivalency of limited resection versus lobectomy according to histology is unknown.

METHODS

We identified patients older than 65 years with stage IA invasive adenocarcinoma or squamous cell carcinoma ≤ 2 cm who were treated with limited resection (wedge or segmentectomy) or lobectomy in the Surveillance, Epidemiology, and End Results-Medicare database. We estimated propensity scores that predicted the use of limited resection and compared survival of patients treated with limited resection versus lobectomy. Treatments were considered equivalent if the upper 95th percentile of the hazard ratio (HR) for limited resection was ≤ 1.25.

RESULTS

Overall, 27% of 2,008 patients with adenocarcinoma and 32% of 1,139 patients with squamous cell carcinoma underwent limited resection. Survival analyses, adjusted for propensity score by using inverse probability weighting, showed that limited resection was not equivalent to lobectomy in patients with adenocarcinoma (HR, 1.21; upper 95% CI,1.34) or squamous cell carcinoma (HR, 1.21; upper 95% CI, 1.39). Although patients with adenocarcinomas treated with segmentectomy had equivalent survival rates to those treated with lobectomy (HR, 0.97; upper 95% CI, 1.07), outcomes of those treated with wedge resection (HR, 1.29; upper 95% CI, 1.42) did not. Among patients with squamous cell carcinoma, neither wedge resection (HR, 1.34; upper 95% CI, 1.53) nor segmentectomy (HR, 1.19; upper 95% CI, 1.36) were equivalent to lobectomy.

CONCLUSION

We found generally that limited resection is not equivalent to lobectomy in older patients with invasive non-small-cell lung cancer ≤ 2 cm in size, although segmentectomy may be equivalent in patients with adenocarcinoma.

Detectability of T1a lung cancer on digital chest radiographs: an observer-performance comparison among 2-megapixel general-purpose, 2-megapixel medical-purpose, and 3-megapixel medical-purpose liquid-crystal display (LCD) monitors

BACKGROUND

There has been no comparison of detectability of small lung cancer between general and medical LCD monitors or no comparison of detectability of small lung cancer between solid and part-solid nodules.

PURPOSE

To compare the detectabilities of T1a lung cancer on chest radiographs on three LCD monitor types: 2-megapixel (MP) for general purpose (General), 2-MP for medical purpose (Medical), and 3-MP-Medical.

MATERIAL AND METHODS

Radiographs from forty patients with T1aN0M0 primary lung cancer (27 solid nodules, 13 part-solid nodules) and 60 patients with no abnormalities on both chest X-ray and computed tomography (CT) were consecutively collected. Five readers assessed 100 cases for each monitor. The observations were analyzed using receiver operating characteristic (ROC) analysis. A jackknife method was used for statistical analysis. A P value of <0.05 was considered significant.

RESULTS

The average AUC for all T1a lung cancer nodule detection using the 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.86, 0.89, and 0.89, respectively; there were no significant differences among them. The average AUC for part-solid nodule detection using a 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.77, 0.86, and 0.89, respectively. There were significant differences between the 2-MP-General and 2-MP-Medical LCD monitors (P = 0.043) and between the 2-MP-General and 3-MP-Medical LCD monitors (P = 0.027). There was no significant difference between the 2-MP-Medical and 3-MP-Medical LCD monitors. The average AUC for solid nodule detection using a 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.90, 0.90, and 0.88, respectively; there were no significant differences among them. The mean AUC values for all and part-solid nodules of the low-experienced readers were significantly lower than those of the high-experienced readers with the 2 M-GP color LCD monitor (P < 0.05).

CONCLUSION

Detectability of part-solid nodules using a general-purpose LCD monitor was significantly lower than those using medical-purpose LCD monitors.

Surgical treatment of early-stage non-small-cell lung cancer

Surgical resection remains the standard of care for functionally operable early-stage non-small-cell lung cancer (NSCLC) and resectable stage IIIA disease. The role of invasive staging and restaging techniques is currently being debated, but they provide the largest biopsy samples which allow for precise mediastinal staging. Different types of operative procedures are currently available to the thoracic surgeon, and some of these interventions can be performed by video-assisted thoracic surgery (VATS) with the same oncological results as those by open thoracotomy. The principal aim of surgical treatment for NSCLC is to obtain a complete resection which has been precisely defined by a working group of the International Association for the Study of Lung Cancer (IASLC). Intraoperative staging of lung cancer is of utmost importance to decide on the extent of resection according to the intraoperative tumour (T) and nodal (N) status. Systematic nodal dissection is generally advocated to evaluate the hilar and mediastinal lymph nodes which are subdivided into seven zones according to the most recent 7th tumour-node-metastasis (TNM) classification. Lymph-node involvement not only determines prognosis but also the administration of adjuvant therapy.

In 2011, a new multidisciplinary adenocarcinoma classification was published introducing the concepts of adenocarcinoma in situ and minimally invasive adenocarcinoma. This classification has profound surgical implications. The role of limited or sublobar resection, comprising anatomical segmentectomy and wide wedge resection, is reconsidered for early-stage lesions which are more frequently encountered with the recently introduced large screening programmes. Numerous retrospective non-randomised studies suggest that sublobar resection may be an acceptable surgical treatment for early lung cancers, also when performed by VATS.

More tailored, personalised therapy has recently been introduced. Quality-of-life parameters and surgical quality indicators become increasingly important to determine the short-term and long-term impact of a surgical procedure. International databases currently collect extensive surgical data, allowing more precise calculation of mortality and morbidity according to predefined risk factors. Centralisation of care has been shown to improve results. Evidence-based guidelines should be further developed to provide optimal staging and therapeutic algorithms.

Association between high-resolution computed tomography findings and the IASLC/ATS/ERS classification of small lung adenocarcinomas in Japanese patients

OBJECTIVES

The detection rate of small pulmonary nodules has recently increased and new techniques have been developed to improve diagnostic yield. The IASLC/ATS/ERS classification demonstrated a difference in prognosis depending on the histological subtypes of lung adenocarcinoma. We evaluated the association between high-resolution computed tomography (HRCT) findings and the classification of these tumors.

METHODS

We reviewed the data of 220 lung adenocarcinoma (≤3 cm) patients who received complete resection with lymph node dissection in our hospital. From the HRCT findings, the tumors were classified into the following 3 categories: pure-solid nodules, part-solid nodules, or pure ground-glass opacity (GGO) nodules. Pathological invasion factor (PIF) was evaluated by the degree of blood vessel invasion, lymphatic permeation, and visceral pleural invasion.

RESULTS

The tumors were classified as pure GGO nodules in 16 patients, part-solid nodules in 91, and pure-solid nodules in 113 from the HRCT findings. Tumors were diagnosed as noninvasive or minimally invasive adenocarcinomas (NMIADs) in 44 patients, and invasive adenocarcinomas (IADs) in 176. Lymph node metastasis was present in 31 patients (14.1%) and PIF in 101 (45.9%). All pure-solid nodules were IADs with a high PIF frequency (75.2%) or with lymph node metastasis (26.5%). All pure GGO nodules were NMIADs or lepidic-predominant adenocarcinomas. Among the part-solid nodules, IAD was detected in 67.0% of the patients and PIF in 16.5%. The consolidation/tumor (C/T) ratio and consolidation size were associated with IAD (optimal cut-off values: 0.4 and 8mm, respectively) and PIF (0.8 and 15 mm, respectively).

CONCLUSIONS

The HRCT findings correlated with the IASLC/ATS/ERS classification and were useful for evaluating the histological nature of the tumors. Most pure-solid tumors had the potential for high-grade malignancy, including PIF and lymph node metastasis. For part-solid tumors, the C/T ratio and consolidation size were important for predicting PIF and for diagnosing IAD according to this classification.

Test-retest reproducibility analysis of lung CT image features

Quantitative size, shape, and texture features derived from computed tomographic (CT) images may be useful as predictive, prognostic, or response biomarkers in non-small cell lung cancer (NSCLC). However, to be useful, such features must be reproducible, non-redundant, and have a large dynamic range. We developed a set of quantitative three-dimensional (3D) features to describe segmented tumors and evaluated their reproducibility to select features with high potential to have prognostic utility. Thirty-two patients with NSCLC were subjected to unenhanced thoracic CT scans acquired within 15 min of each other under an approved protocol. Primary lung cancer lesions were segmented using semi-automatic 3D region growing algorithms. Following segmentation, 219 quantitative 3D features were extracted from each lesion, corresponding to size, shape, and texture, including features in transformed spaces (laws, wavelets). The most informative features were selected using the concordance correlation coefficient across test-retest, the biological range and a feature independence measure. There were 66 (30.14%) features with concordance correlation coefficient ≥ 0.90 across test-retest and acceptable dynamic range. Of these, 42 features were non-redundant after grouping features with R (2) Bet ≥ 0.95. These reproducible features were found to be predictive of radiological prognosis. The area under the curve (AUC) was 91% for a size-based feature and 92% for the texture features (runlength, laws). We tested the ability of image features to predict a radiological prognostic score on an independent NSCLC (39 adenocarcinoma) samples, the AUC for texture features (runlength emphasis, energy) was 0.84 while the conventional size-based features (volume, longest diameter) was 0.80. Test-retest and correlation analyses have identified non-redundant CT image features with both high intra-patient reproducibility and inter-patient biological range. Thus making the case that quantitative image features are informative and prognostic biomarkers for NSCLC.

Using the CT features to differentiate invasive pulmonary adenocarcinoma from pre-invasive lesion appearing as pure or mixed ground-glass nodules

OBJECTIVE

To differentiate pre-invasive lesion from invasive pulmonary adenocarcinoma (IPA) appearing as ground-glass nodules (GGNs) using CT features.

METHODS

149 GGNs were enrolled in this study, with 74 pure GGNs (p-GGNs) and 75 mixed GGNs (m-GGNs). Firstly, univariate analysis was used to analyse the difference of CT features between pre-invasive lesion and IPA. Then, multivariate analysis was conducted to identify variables that could independently differentiate pre-invasive lesion from IPA. Receiver operating characteristic curve analysis was performed to evaluate the differentiating value of identified variables.

RESULTS

In the p-GGNs, multivariate analysis showed that the amount of blood vessels was an independent risk factor. Using the amount of blood vessels "≥1" as the diagnostic criterion, we could diagnose IPA with a sensitivity of 100%. Using the amount of blood vessels "=0" as the diagnostic criterion, we could diagnose pre-invasive lesions with a specificity of 100%. In the m-GGNs, multivariate analysis showed that the volume of solid portion (VSolid) and pleural indentation were two independent risk factors. One further model was constructed using these two variables: model = 2.508 × (VSolid + 1.407) × (pleural indentation - 1.016). Using the new model, improved diagnostic ability was achieved compared with using VSolid or pleural indentation alone.

CONCLUSION

The amount of blood vessels through the p-GGNs would be an important criterion during clinical management, while VSolid and pleural indentation seemed important for m-GGNs. Moreover, the new model could further improve the differentiating value for m-GGNs.

ADVANCES IN KNOWLEDGE

CT features are useful in differentiating pre-invasive lesion from IPA appearing as GGNs.

Semiquantitative Computed Tomography Characteristics for Lung Adenocarcinoma and Their Association With Lung Cancer Survival

In this study we developed 25 computed tomography descriptors among 117 patients with lung adenocarcinoma to semiquantitatively assess their association with overall survival. Pleural attachment was significantly associated with an increased risk of death and texture was most important for distinguishing histological subtypes. This approach has the potential to support automated analyses and develop decision-support clinical tools.

BACKGROUND

Computed tomography (CT) characteristics derived from noninvasive images that represent the entire tumor might have diagnostic and prognostic value. The purpose of this study was to assess the association of a standardized set of semiquantitative CT characteristics of lung adenocarcinoma with overall survival.

PATIENTS AND METHODS

An initial set of CT descriptors was developed to semiquantitatively assess lung adenocarcinoma in patients (n = 117) who underwent resection. Survival analyses were used to determine the association between each characteristic and overall survival. Principle component analysis (PCA) was used to determine characteristics that might differentiate histological subtypes.

RESULTS

Characteristics significantly associated with overall survival included pleural attachment (P < .001), air bronchogram (P = .03), and lymphadenopathy (P = .02). Multivariate analyses revealed pleural attachment was significantly associated with an increased risk of death overall (hazard ratio [HR], 3.21; 95% confidence interval [CI], 1.53-6.70) and among patients with lepidic predominant adenocarcinomas (HR, 5.85; 95% CI, 1.75-19.59), and lymphadenopathy was significantly associated with an increased risk of death among patients with adenocarcinomas without a predominant lepidic component (HR, 3.07; 95% CI, 1.09-8.70). A PCA model showed that texture (ground-glass opacity component) was most important for separating the 2 subtypes.

CONCLUSION

A subset of the semiquantitative characteristics described herein has prognostic importance and provides the ability to distinguish between different histological subtypes of lung adenocarcinoma.

Observer Variability for Classification of Pulmonary Nodules on Low-Dose CT Images and Its Effect on Nodule Management

PURPOSE

To examine the factors that affect inter- and intraobserver agreement for pulmonary nodule type classification on low-radiation-dose computed tomographic (CT) images, and their potential effect on patient management.

MATERIALS AND METHODS

Nodules (n = 160) were randomly selected from the Dutch-Belgian Lung Cancer Screening Trial cohort, with equal numbers of nodule types and similar sizes. Nodules were scored by eight radiologists by using morphologic categories proposed by the Fleischner Society guidelines for management of pulmonary nodules as solid, part solid with a solid component smaller than 5 mm, part solid with a solid component 5 mm or larger, or pure ground glass. Inter- and intraobserver agreement was analyzed by using Cohen κ statistics. Multivariate analysis of variance was performed to assess the effect of nodule characteristics and image quality on observer disagreement. Effect on nodule management was estimated by differentiating CT follow-up for ground-glass nodules, solid nodules 8 mm or smaller, and part-solid nodules smaller than 5 mm from immediate diagnostic work-up for solid nodules larger than 8 mm and part-solid nodules 5 mm or greater.

RESULTS

Pair-wise inter- and intraobserver agreement was moderate (mean κ, 0.51 [95% confidence interval, 0.30, 0.68] and 0.57 [95% confidence interval, 0.47, 0.71]). Categorization as part-solid nodules and location in the upper lobe significantly reduced observer agreement (P = .012 and P < .001, respectively). By considering all possible reading pairs (28 possible combinations of observer pairs × 160 nodules = 4480 possible agreements or disagreements), a discordant nodule classification was found in 36.4% (1630 of 4480), related to presence or size of a solid component in 88.7% (1446 of 1630). Two-thirds of these discrepant readings (1061 of 1630) would have potentially resulted in different nodule management.

CONCLUSION

There is moderate inter- and intraobserver agreement for nodule classification by using current recommendations for low-radiation-dose CT examinations of the chest. Discrepancies in nodule categorization were mainly caused by disagreement on the size and presence of a solid component, which may lead to different management in the majority of cases with such discrepancies. (©) RSNA, 2015.

Impact of the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification of stage IA adenocarcinoma of the lung: Correlation between computed tomography images and EGFR and KRAS gene mutations

The aim of the present study was to compare pathological diagnoses, as determined by the new International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification, with conventional radiological features. In addition, the present study aimed to evaluate the correlation among clinical characteristics, computed tomography (CT) images and gene mutation status in patients with stage IA adenocarcinoma of the lung. A total of 212 patients with stage IA lung adenocarcinoma were included in the study. The patients were classified into pure ground-glass opacity (pGGO), mixed GGO (mGGO) and solid GGO (sGGO) by CT imaging. Histological subtype was classified according to the IASLC/ATS/ERS classification of lung adenocarcinoma. In addition, epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma (KRAS) mutation assays were performed, and 36.8% of patients (78/212) were determined to have an EGFR mutation, while 8.5% of patients (18/212) were found to have a KRAS mutation. According to the IASLC/ATS/ERS classification, 44 cases were diagnosed as adenocarcinoma in situ (AIS; 20.8%), 62 cases were diagnosed as minimally invasive adenocarcinoma (MIA; 29.2%) and 106 cases were classified as invasive adenocarcinoma (IAC; 50.0%). pGGO image patterns were observed in 39.2% of patients (n=83), while mGGO and sGGO patterns were observed in 28.8% (n=61) and 32.0% (n=68) of patients, respectively. From pGGO to sGGO, cases of AIS and MIA were shown to have a decreasing trend, while IAC cases exhibited an increasing trend (P=0.036). Analysis of the correlation between CT image patterns and gene mutations demonstrated that L858R point mutations, exon 19 deletions and KRAS mutations were more common in lesions with a lower GGO proportion (P=0.029, 0.027 and 0.018, respectively). Therefore, according to the IASLC/ATS/ERS classification, GGO imaging patterns were shown to correlate with subtypes of adenocarcinomas. In addition, EGFR and KRAS mutations were found to be associated with lesions with a low GGO proportion. Therefore, analysis of GGO lesions may offer useful indications of the histological subtype of an adenocarcinoma in patients with stage IA lung adenocarcinoma, and predictive value for EGFR and KRAS mutations.

Management of ground-glass opacities: should all pulmonary lesions with ground-glass opacity be surgically resected?

Pulmonary nodules with ground-glass opacity (GGO) are frequently observed and will be increasingly detected. GGO can be observed in both benign and malignant conditions, including lung cancer and its preinvasive lesions. Atypical adenomatous hyperplasia and adenocarcinoma in situ are typically manifested as pure GGOs, whereas more advanced adenocarcinomas may include a larger solid component within the GGO region. The natural history of GGOs has been gradually clarified. Approximately 20% of pure GGOs and 40% of part-solid GGOs gradually grow or increase their solid component, whereas others remain unchanged for years. Therefore, it remains unclear whether all pulmonary lesions with GGO should be surgically resected or whether lesions without changes may not require resection. To distinguish GGOs with growth from those without growth, a 3-year follow-up observation period is a reasonable benchmark based on the data that the volume-doubling time (VDT) of pure GGOs ranges from approximately 600 to 900 days and that of part-solid GGOs ranges from 300 to 450 days. Future studies on the genetic differences between GGOs with growth and those without growth will help establish an appropriate management algorithm.

Preoperative flexible bronchoscopy in patients with persistent ground-glass nodule

There are no accurate data on the diagnostic value of preoperative flexible bronchoscopy (FB) for persistent ground-glass nodule (GGN) of the lung. We evaluated the value of preoperative FB in patients with suspected GGN-type lung cancer. We retrospectively searched a database for subjects who had ‘ground-glass opacity’, ‘non-solid nodule’, ‘part-solid nodule’, or ‘sub-solid nodule’ on chest computed tomography reports between February 2004 and March 2012. Patients who had infiltrative ground-glass opacity lesions, mediastinal lymphadenopathy, or pleural effusion, focal ground-glass opacity lesions >3 cm, and were lost to follow-up were excluded. We assessed the diagnostic value of preoperative FB in patients with persistent GGNs who underwent surgical resection. In total, 296 GGNs were evaluated by FB in 264 patients with persistent GGNs who underwent preoperative FB and surgical resection. The median size of the GGNs was 18 mm; 135 (46%) were pure GGN and 161 (54%) were part-solid GGN. No visible tumor or unsuspected endobronchial metastasis was identified by preoperative FB. Only 3 (1%, 3/208) GGNs were identified preoperatively as malignant by bronchial washing cytology; all were part-solid GGNs. No other etiology was identified by FB. Of the GGNs, 271 (91%) were subsequently confirmed as malignant and 25 (9%) were confirmed as benign at surgical resection. Consequently, the overall diagnostic sensitivity and negative predictive value of preoperative FB on a per-nodule basis was 1% (3/271) and 8% (25/293), respectively. The preoperative FB did not change the surgical strategy. Preoperative FB did not add much to the evaluation of persistent GGNs of the lung. Routine preoperative FB may have limited value in surgical candidates with small persistent pure GGNs.

Is lower zone mediastinal nodal dissection always mandatory for lung cancer in the lower lobe?

PURPOSE

Dissection of the lower zone mediastinal nodes is mandatory during systematic nodal dissection for lung cancer. However, the significance of lower zone lymph node metastasis (LZM) in lung cancer remains unclear. Therefore, we aimed to identify the predictive factors for LZM in patients with lower lobe lung cancer.

METHODS

A retrospective study was conducted on 257 patients with lower lobe lung cancer, in whom pulmonary resection and mediastinal nodal dissection were performed between 2009 and 2013. The radiological factors on thin-section computed tomography scans (TSCT) and several conventional clinical factors were evaluated as possible predictors of LZM.

RESULTS

Twenty (7.8 %) patients exhibited LZM. The majority of the tumors were especially located in segment 10 (50 %). All patients showed a solid appearance on TSCT. In a univariate analysis, the tumor location, a solid appearance and the clinical T factor significantly predicted LZM (p = 0.011, 0.005, 0.018). Furthermore, based on a multivariate analysis, the tumor location in segment 10 significantly predicted LZM in patients with lower lobe solid lung cancer (p = 0.031).

CONCLUSION

The appropriate surgical strategy for lower zone lymph node dissection should be selected based on the tumor location and the findings of TSCT, due to the high frequency of LZM (19.6 %), especially in patients with pure solid lung cancer in segment 10.

Genetic features of pulmonary adenocarcinoma presenting with ground-glass nodules: the differences between nodules with and without growth

BACKGROUND

Pulmonary ground-glass nodules (GGNs) include both malignant and benign lesions. Some GGNs become larger, whereas others remain unchanged for years. We have previously reported that smoking history and large diameters are predictors for growth. However, the genetic differences among GGNs remain unclear.

PATIENTS AND METHODS

GGNs with ground-glass component of ≥50% on a thin-section computed tomography scan that were resected between 2012 and 2014 were evaluated for clinicopathological features and the presence of EGFR/KRAS/ALK/HER2 mutations. 'Incidence of 2-mm growth' and 'Time to 2-mm growth' were analyzed according to the mutational status.

RESULTS

Among 104 GGNs in 96 patients, this study included 3 atypical adenomatous hyperplasia (AAH), 19 adenocarcinoma in situ (AIS), 27 minimally invasive adenocarcinoma (MIA), and 55 invasive adenocarcinoma (IA). Among the 71 lesions evaluable for growth, 30 GGNs exhibited growth and 5 lesions remained unchanged for ≥2 years before surgery was carried out. We identified mutations or rearrangements in 75% of GGNs (78/104). EGFR mutations were noted in 64% of samples, KRAS in 4%, ALK in 3%, and HER2 in 4%. The remaining 26 quadruple-negative tumors were significantly associated with AAH/AIS (P < 0.01) and no-growth (P < 0.01) compared with driver mutation-positive tumors, whereas EGFR mutation-positive tumors were correlated with MIA/IA (P < 0.01) and growth (P < 0.01) compared with EGFR-negative tumors.

CONCLUSIONS

Three fourths of resected GGNs were positive for EGFR, KRAS, ALK, or HER2 mutations. Quadruple-negative tumors were associated with a lack of GGN growth, whereas EGFR mutation-positive tumors displayed a correlation with growth.

Predictive value of 18F-FDG PET and CT morphologic features for recurrence in pathological stage IA non-small cell lung cancer

Patients with pathological stage IA non-small cell lung cancer (NSCLC) may relapse despite complete surgical resection without lymphovascular invasion. A method of selecting a high-risk group for adjuvant therapy is necessary. The aim of this study was to assess the predictive value of F-fluorodeoxyglucose (FDG) uptake and the morphologic features of computed tomography (CT) for recurrence in pathological stage IA NSCLC.One hundred forty-five patients with pathological stage IA NSCLC who underwent pretreatment with FDG positron emission tomography and CT evaluations were retrospectively enrolled. The associations among tumor recurrence and patient characteristics, maximal standard uptake value (SUVmax) of primary tumors, and CT imaging features were investigated using univariate and multivariate analyses. A receiver operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors.Tumor recurrence developed in 21 (14.5%) of the 145 patients, and the 5-year recurrence-free survival rate was 77%. The univariate analysis demonstrated that SUVmax, the grade of histological differentiation, tumor size, and the presence of bronchovascular bundle thickening were significant predictive factors (P < 0.05). A higher SUVmax (≥2.5) (P = 0.021), a lower ground-glass opacity ratio (≤17%) (P = 0.014), and the presence of bronchovascular bundle thickening (P = 0.003) were independent predictive factors of tumor recurrence in the multivariate analysis. The use of this predictive model yielded a greater area under the ROC curve (0.877), which suggests good discrimination.The combined evaluation of FDG uptake and CT morphologic features may be helpful in the prediction of recurrence in patients with pathological stage IA NSCLC and in the stratification of a high-risk group for postoperative adjuvant therapy or prospective clinical trials.

The 2011 IASLC/ATS/ERS pulmonary adenocarcinoma classification: a landmark in personalized medicine for lung cancer management

In 2011, three authoritative academic communities, International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society (IASLC/ATS/ERS), published a novel lung adenocarcinoma histologic classification. The major modifications of this classification include the abolishment of the term "bronchioloalveolar carcinoma (BAC)", the establishment of new classification systems for resection and small biopsy or cytology specimens, the emphasis of molecular test and comprehensive histologic evaluation for tumor specimens, etc. This new lung adenocarcinoma classification signifies the era of personalized medicine comes to real-world practice in lung cancer field. Here, we introduce the background why the lung adenocarcinoma classification needs to be revised, and what we should consider in clinical practice according to this new classification.

Correlation between the size of the solid component on thin-section CT and the invasive component on pathology in small lung adenocarcinomas manifesting as ground-glass nodules

INTRODUCTION

We aimed to evaluate the correlation between the size of the solid component on thin-section computed tomography (CT) and invasive component on pathology in small lung adenocarcinomas manifesting as subsolid nodules.

METHODS

Fifty-nine subsolid nodules in 58 patients were evaluated. The maximum diameters of subsolid nodules and the solid component on CT were measured by two radiologists in three-dimensional (3D) and two-dimensional (2D) planes using in-house software. In addition, the maximum diameters of the tumor and invasive component were measured on pathology by two pathologists. CT measurements were compared with pathologic measurements.

RESULTS

There was a strong correlation between the size of the solid component on CT and invasive component on pathology, as well as the size of subsolid nodules and the tumor size (r = 0.82-0.87 for 3D measurement, 0.72-0.88 for 2D measurement; p < 0.0001). The size of subsolid nodules in 3D and 2D measurements was significantly larger than tumor size (p < 0.0001). In regard to measurement of the solid component, 3D measurements tended to be larger than the size of the invasive component whereas 2D measurement tended to be similar to the size of the invasive component. By applying a size criteria of solid component that was 3 mm or lesser in maximum diameter, preinvasive and minimally invasive adenocarcinoma was predicted with a specificity of 100% (28 of 28).

CONCLUSION

We found a significant correlation between the size of the solid component on thin-section CT and the invasive component on pathology.

Prognostic evaluations of small size lung cancers by 18F-FDG PET/CT and thin-section CT

PURPOSE

Primary lung cancers have varying prognoses, even for tumors ≤3cm in diameter. Thus, a thorough evaluation is necessary for therapeutic planning. Two imaging biomarkers have been shown to be useful for predicting primary lung cancer prognosis: maximum standardized uptake values (SUVmax) on fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and the consolidation/tumor (C/T) ratio defined as the maximum diameter of consolidation within a tumor to the maximum tumor diameter on thin-section computed tomography (TSCT). We compared these biomarkers for predicting post-surgical recurrence in patients with small lung cancers.

MATERIALS AND METHODS

Clinical records, post-operative pathologic findings, and pre-operative PET/CT and TSCT images were reviewed. Solitary primary lung cancers of ≤3cm in diameter after surgical resection were selected for analysis. SUVmax and C/T ratios were recorded. Kaplan-Meier survival curves and Cox hazards ratios were used to identify independent predictors of lung cancer recurrence from among age, gender, surgical procedure, lesion size, C/T ratio, and SUVmax.

RESULTS

A total of 169 patients (114 males and 55 females; age range: 34-87 years) with solitary lung cancers were evaluated. The median post-operative follow-up period was 42 months. Twenty-eight patients had cancer recurrence with significantly higher SUVmax (p<0.001) and C/T ratios (p<0.001) than patients without recurrence. Disease-free survival was significantly reduced for SUVmax of ≥2.5 vs. SUVmax of <2.5 (p<0.001) or for a C/T ratio of ≥50% vs. a C/T ratio of <50% (p=0.030). For 19 patients with C/T ratios of <50%, none had a post-operative recurrence. A Cox hazards ratio model showed that only SUVmax was an independent predictor of recurrence (hazards ratio=1.324; p<0.001).

CONCLUSION

SUVmax on FDG-PET/CT was a significant imaging biomarker relevant to the prognosis of patients with lung cancers, and was superior to the C/T ratio on TSCT for predicting postoperative recurrence, particularly for solid type lung cancer.

Synchronous triple primary lung cancers: a case report

Synchronous primary lung cancers are relatively rare. The accurate diagnosis remains challenging, despite of the routine use of bronchoscopy and computed tomography (CT) of the chest. Herein we report a case of synchronous triple primary cancers of the right lung in a 72-year-old male patient in whom each tumor presented distinct CT imaging findings.

The role of octreotate scan in discrimination of solitary pulmonary nodule

Solitary pulmonary nodule (SPN) is one of the most controversial clinical findings in patients. The aim of this study is to use (99m)Tc-ethylenediamine diacetic acid/hydrazine nicotinamide (HYNIC)-TATE scan technique to evaluate nodules. From 2008 to 2010, 21 patients with SPN underwent (99m)Tc-HYNIC-TATE scan after the initial assessment with high-resolution computed tomography and then accurate histopathologic diagnosis was established by trans-thoracic needle biopsy, Video Assisted Thoracic Surgery and thoracotomy. After demographic evaluations, specificity and sensitivity of this method was studied. A total of 21 patients were included in our study, of which 12 patients were male and 9 were female. Their mean age was 45 ± 14.3 years. About 43% of the patients were symptom-free and in patients with pulmonary complaints, the most prevalent symptom was cough. Final histopathology tests and clinical follow-up proved that 14 cases (67%) were benign and 7 (33%) were malignant. The diagnostic technique used in our study had no false negative and there were only 3 cases of false positive. Sensitivity and specificity of this method are 100% and 79%, respectively and the diagnostic accuracy is 86%. (99m)Tc-HYNIC-TATE scan can be helpful in evaluating patients with SPN and to reach a sensible decision on the method of treatment.

Partly solid pulmonary nodules: waiting for change or surgery outright?

OBJECTIVES

It has been assumed that if the prognosis and rate of lymph node metastases differ between two groups of patients being followed up for partly solid tumours, those with an increased solid component and those without change, these differences can help to decide on the time of surgery for patients with partly solid tumours. Therefore, this study compared the differences in pathological results and prognosis after surgical resection between patients with no change and and those with change in partly solid tumours during the preoperative period.

METHODS

Surgery was performed in patients who had an increased size of the solid component during the follow-up observation of partly solid tumours, as well as patients who had no change in the size of the solid component during a certain period of time. The 'No change group' in this study comprised those who had no change in at least two chest computed tomography scans during a minimum period of 6 months, but who underwent surgery.

RESULTS

Twenty-four patients were enrolled in this study. Among these patients, 14 were included in the No change group, and ten were included in the 'Change group'. There was no difference in the ratio of other postoperative pathological results, adenocarcinoma in situ, minimally invasive adenocarcinoma or invasive adenocarcinoma between the two groups. There was no difference in the pathological size of the tumour, including the in situ component between the two groups, but the size of the invasive component in the Change group was 2.5-fold that of the No change group, a statistically significant difference. During the median follow-up period of 59 months, neither recurrence nor cancer-related deaths occurred.

CONCLUSIONS

The pathological results and prognosis of lung cancer patients with persistent partly solid tumours who develop changes in their lesions after a certain period of follow-up time were not different from those of patients who did not develop any changes in the lesions. Therefore, surgery can be deferred until those lesions demonstrate changes in size or growth in their solid component when the overall size of ground-glass opacity (GGO) is less than 3 cm and the proportion of GGO is greater than 50%.

Volume and mass doubling times of persistent pulmonary subsolid nodules detected in patients without known malignancy

PURPOSE

To evaluate volume doubling time (VDT) and mass doubling time (MDT) of persistent pulmonary subsolid nodules (SSNs) followed-up with low-dose (LD) computed tomography (CT) in patients without a history of malignancy.

MATERIALS AND METHODS

This retrospective institutional review board-approved study, with waiver of patient informed consent, included 97 SSNs in 97 patients (45 men, 52 women; median age, 58 years; range, 37-87 years) in whom at least two LD CT scans were obtained, with 3-month or longer follow-up interval and median follow-up of 633 days. SSNs were categorized into pure ground-glass nodules (GGNs) (group A), part-solid GGNs with solid components of 5 mm or smaller (group B), and part-solid GGNs with solid components larger than 5 mm (group C). Three-dimensional manual segmentation for all SSNs was performed on initial and latest follow-up LD CT scans; subsequently, VDTs and MDTs were calculated and were compared among groups by using Kruskal-Wallis test, followed by the Dunn procedure with Bonferroni correction for volume-growing SSNs and mass-growing SSNs.

RESULTS

Volume growth was thus: 12 of 63 SSNs (19%), group A; nine of 23 SSNs (39%), group B; and eight of 11 SSNs (73%), group C. Median VDT was thus: 1832.3 days (range, 1230.7-4537.3 days), group A; 1228.5 days (range, 934.7-4617.7 days), group B; and 759.0 days (range, 376.4-941.5 days), group C. Mass growth was thus: 17 of 63 SSNs (27%), group A; 11 of 23 SSNs (48%), group B; and nine of 11 SSNs (82%), group C. Median MDT was 1556.1 days (range, 642.5-3564.5 days) for group A, 1199.9 days (range, 838.6-2578.7 days) for group B, and 627.7 days (range, 340.0-921.2 days) for group C. Median VDTs and MDTs of groups A and B were significantly longer than those of group C (P < .01).

CONCLUSION

Pure GGNs and part-solid GGNs with solid components of 5 mm or smaller show significantly longer VDTs and MDTs than do part-solid GGNs with solid components larger than 5 mm. Online supplemental material is available for this article.

Differentiation of lung neoplasms with lepidic growth and good prognosis from those with poor prognosis using computer-aided 3D volumetric CT analysis and FDG-PET

BACKGROUND

Many studies have reported that transverse computed tomography (CT) imaging findings correlate with prognosis of patients with small peripheral lung neoplasm with lepidic growth. However, no studies have examined this correlation with the aid of three-dimensional (3D) CT data.

PURPOSE

To determine the most efficacious imaging factor for differentiation of lepidic growth type lung neoplasms with good prognosis from those with poor prognosis.

MATERIAL AND METHODS

We evaluated CT findings, nodule patterns, SUVmax on FDG-PET/CT, as well as nodule volume and ratios of solid parts to nodule volume that were semi-automatically measured on CT images of 64 pulmonary nodules of ≤ 2 cm in 60 consecutive patients (24 men and 36 women; mean age, 65 years). For logistic modeling, we used all of the significant factors observed between the neoplasms with good and with poor prognosis as independent variables to estimate the statistically significant factors for discriminating invasive adenocarcinomas with lepidic growth (lesions with poor prognosis, n=42) from the other neoplasms, including preinvasive lesions (lesions with good prognosis, n=22), resulting in a recommendation for the optimal criterion for predicting lesions with poor prognosis.

RESULTS

The logistic regression model identified the ratio of the solid part to the whole volume of a pulmonary nodule as the only significant factor (P=0.04) for differentiating lepidic growth type lung neoplasms with good prognosis from those with poor prognosis. A ratio of 0.238 or more showed the highest discriminatory accuracy of 84% with 91% sensitivity and 76% specificity.

CONCLUSION

Computer-aided analyses of pulmonary nodules proved most useful for establishing the optimal criterion for differentiation of lepidic growth type lung neoplasms with good prognosis from those with poor prognosis.

Value of ¹⁸F-FDG uptake on PET/CT and CEA level to predict epidermal growth factor receptor mutations in pulmonary adenocarcinoma

PURPOSE

The identification of the mutation status of the epidermal growth factor receptor (EGFR) is important for the optimization of treatment in patients with pulmonary adenocarcinoma. The acquisition of adequate tissues for EGFR mutational analysis is sometimes not feasible, especially in advanced-stage patients. The aim of this study was to predict EGFR mutation status in patients with pulmonary adenocarcinoma based on (18)F-fluorodeoxyglucose (FDG) uptake and imaging features in positron emission tomography/computed tomography (PET/CT), as well as on the serum carcinoembryonic antigen (CEA) level.

METHODS

We retrospectively reviewed 132 pulmonary adenocarcinoma patients who underwent EGFR mutation testing, pretreatment FDG PET/CT and serum CEA analysis. The associations between EGFR mutations and patient characteristics, maximal standard uptake value (SUVmax) of primary tumors, serum CEA level and CT imaging features were analyzed. Receiver-operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors.

RESULTS

EGFR mutations were identified in 69 patients (52.2 %). Patients with SUVmax ≥6 (p = 0.002) and CEA level ≥5 (p = 0.013) were more likely to have EGFR mutations. The CT characteristics of larger tumors (≥3 cm) (p = 0.023) and tumors with a nonspiculated margin (p = 0.026) were also associated with EGFR mutations. Multivariate analysis showed that higher SUVmax and CEA level, never smoking and a nonspiculated tumor margin were the most significant predictors of EGFR mutation. The combined use of these four criteria yielded a higher area under the ROC curve (0.82), suggesting a good discrimination.

CONCLUSION

The combined evaluation of FDG uptake, CEA level, smoking status and tumor margins may be helpful in predicting EGFR mutation status in patients with pulmonary adenocarcinoma, especially when the tumor sample is inadequate for genetic analysis or genetic testing is not available. Further large-scale prospective studies are needed to validate these results.