The Radiographic Study Of Lung Adenocarcinoma According To IASLC/ATS/ERS Classification

Part ITime trends in epidemiologic characteristics and imaging features of lung adenocarcinoma:a population study of21113cases[Abstract] Objective This study aims to describe time trends of epidemiologic characteristics and imaging features over14years among histologically confirmed lung adenocarcinoma in the Cancer Hospital of Chinese Academy of Medical Sciences and to discuss the possible reasons for these changes. Methods Data from21113pathologically confirmed lung cancer patients from January1999to December2012was analyzed retrospectively. The cases were categorized into nine histological subtypes according to the WHO Classification of Tumors2004. According to the WHO age classification2004, study subjects were divided into three age groups:young people (≤44years), middle-aged people (45-59years) and elderly people (≤60years).7202adenocarcinoma patients with complete pathologic stage were divided into early-stage (pT1N0M0) and non-early-stage, and the proportion of early-stage adenocarcinoma was calculated. Preoperative HRCT images were available and reviewed in5439lung adenocarcinoma patients since2005. The lesions were divided into two groups according to their attenuation type:solid nodules and subsolid nodules. Time trends of adenocarcinoma proportion in lung cancer cases, gender distribution, age at diagnosis, the proportion of early-stage adenocarcinoma and imaging features were investigated. SPSS statistical software version17.0was used for all data analyses, α=0.05. Results The proportion of adenocarcinoma increased during the14years (P<0.001). The ratio of female to male in adenocarcinoma was higher than both squamous cell carcinoma and total lung cancer cases (P<0.001).The ratio of female to male in adenocarcinoma increased but not significantly (P=0.06) during the14years. The median age at diagnosis of adenocarcinoma patients was younger than that of both squamous cell carcinoma and total lung cancer (P<0.001). The proportion of middle-aged people increased in total lung cancer cases (P<0.001). When stratified by lung cancer histopathologic subtypes, this trend was also observed in adenocarcinoma(P=0.001) and squamous cell carcinoma (P=0.007). Significantly difference of early-stage lung adenocarcinoma proportion was observed among the14years (P<0.001). The proportion of early-stage lung adenocarcinoma was positive correlation with year period from2008to2012(r=0.874, P<0.001). The proportion of subsolid nodules in adenocarcinoma increased (P=0.001) from2005to2012. Conclusion The data suggested that the proportion of adenocarcinoma increased from1999to2012and middle-aged, female patients, early-stage lung adenocarcinoma and subsolid nodules on CT images gradually increased, which may be contributed by a change in smoking habits and increased application of CT. Part IIRadiographic analysis of clinical stage T1N0M0(cT1N0M0) lung adenocarcinoma using IASLC/ATS/ERS classification[Abstract] Objective To analyze the radiographic features of cT1N0M0lung adenocarcinomas according to IASLC/ATS/ERS Classification of Lung Adenocarcinoma. Methods Pathological and radiographic data of375surgically resected cT1N0M0lung adenocarcinomas from January2005to December2012were retrospectively investigated. All patients underwent HRCT and among which147patients underwent PET/CT. Radiographic features including tumor diameter, tumor attenuation, the proportion of ground glass opacity component, the proportion of solid component, tumor location, tumor contour, intratumoral necrosis, vacuole sign or cavity/cyst in tumor and SUVmax were analyzed. All surgically resected specimens were reviewed according to IASLC/ATS/ERS classification and the invasive patterns of tumor were semiquantitatively recorded in5%increments. Invasive adenocarcinomas were graded by using a three-tier grading system. Grade1corresponded to the lepidic pattern of invasive adenocarcinoma. Grade2included tumors that showed acinar or papillary patterns. Grade3included the tumors that showed micropapillary or solid patterns. The correlation between radiographic features and histopathologic subtypes were evaluated by Chi-square test, the Student t test, One-way Analysis of Variance, multiple logistic regression analysis and ROC analysis, a=0.05. Results Among375cT1N0M0lung adenocarcinoma, preinvasive lesion was detected in41patients (10.9%), minimally invasive adenocarcinoma in51(13.6%), invasive adenocarcinoma in273(72.8%) and variants of invasive adenocarcinoma in10(2.7%). In273invasive adenocarcinomas,49(17.9%) were assessed as grade1,208(76.2%) as grade2and16(5.9%) as grade3. Significant differences in tumor diameter (P<0.001), tumor attenuation (P<0.001), tumor contour (P<0.001), intratumoral necrosis (P=0.002), vacuole sign or cavity/cyst in tumor (P<0.001), the proportion of ground glass opacity component (P<0.001), the proportion of solid component (P<0.001) and SUVmax (P=0.018) between invasive lesion and non-invasive lesion were observed. The largest area under curve of ROC in respect to the invasion of adenocarcinoma was the proportion of solid component (0.875, P<0.001) in single factor analysis, which is slightly smaller than the co-detection of multiple factors Y (0.879, P<0.001) but without statistical significance (P=0.627). Significant differences in tumor diameter (P=0.015), tumor attenuation (P<0.001), intratumoral necrosis (P=0.001), the proportion of ground glass opacity component (P<0.001) and the proportion of solid component (P<0.001) among different histopathological grades were observed. Conclusion Both of the solid component proportion and Y were useful for diagnosis of invasive adenocarcinoma in cT1N0M0lung adenocarcinomas; the larger tumor diameter, the less proportion of ground glass opacity component, the more proportion of solid component and the presence of intratumoral necrosis in invasive adenocarcinoma predicted higher histopathological grade. The radiographic features probably predict histopathological grade, which may help preoperative evaluation and plan individual surgical treatment. Part ⅢThe value of radiographic and histopathologic features of primary tumor for predicting pathologic node-negative in clinical stage T1N0M0(cT1N0M0) lung adenocarcinoma[Abstract] Objective To analyze the value of radiographic and histopathologic features of primary tumor for predicting pathologic node-negative in cT1N0M0lung adenocarcinoma, in order to establish optimal surgical strategy for avoiding systematic lymph node dissection in cT1N0M0lung adenocarcinoma. Methods Histopathologic and radiographic data of364surgically resected cT1N0M0lung adenocarcinomas with systematic lymph node dissection from January2005to December2012were retrospectively investigated. Histopathologic features (histologic subtype, differentiation degree) and radiographic features (tumor diameter, tumor attenuation, the proportion of GGO component, the proportion of solid component, tumor location, tumor contour, intratumoral necrosis, vacuole sign or cavity/cyst in tumor, SUVmax) were analyzed. All surgically resected specimens were reviewed according to IASLC/ATS/ERS classification. The differences of radiographic and histopathologic features between pathologic node-positive and pathologic node-negative were evaluated. The values of different features of primary tumor for predicting pathologic node-negative in cT1N0M0lung adenocarcinoma were compared. Results Among364cT1N0M0lung adenocarcinoma patients, pathologic node-negative was detected in321patients (88.2%). Decrease trend were observed in both histologic grade and differentiation grade (P<0.001). Significant differences in primary tumor diameter (P=0.001), attenuation (P<0.001), location (P=0.011), contour(P=0.007), the proportion of GGO component (P <0.001), the proportion of solid component (P<0.001) and SUVmax (P=0.001) between pathologic node-positive and pathologic node-negative were observed, among which the proportion of solid component was independent factor of pathologic node-negative in cT1N0M0lung adenocarcinoma. Clinical T1N0M0lung adenocarcinoma patients with a solid component proportion of no more than16.1%were observed to have no lymph node metastasis. Conclusion Lymph nodes status in cT1N0M0lung adenocarcinoma was related to diameter, attenuation, location, contour, the proportion of GGO component, and the proportion of solid component and SUVmax of primary tumor. A proportion of solid component no more than16.1%in primary tumor may be helpful for avoiding systematic lymph node dissection in cT1N0M0lung adenocarcinoma patients. Part IVEpidermal growth factor receptor effective mutation in clinical T1N0M0(cT1N0M0) lung adenocarcinomas:study of related factors on radiology and histopathology[Abstract] Objective To investigate clinical, pathological and radiographic factors associated with epidermal growth factor receptor (EGFR) effective mutation in cT1N0Mo lung adenocarcinomas, and to determine which patients should be encouraged to test for EGFR mutations. Methods In92surgically resected cT1N0M0lung adenocarcinomas, EGFR mutation was determined by direct DNA sequencing. Data of clinical factors (age, sex, smoking status), pathological factor (histologic subtypes according IASLC/ATS/ERS classification of lung adenocarcinoma, lepidic component in tumor, differentiation degree, lymph node metastasis, pathological stage) and radiographic factors (tumor diameter, tumor attenuation, the proportion of ground glass opacity component, the proportion of solid component, tumor location, tumor contour, intratumoral necrosis, vacuole sign or cavity/cyst in tumor, SUVmax) were organized. Distribution of EGFR effective mutation according to the related factors were evaluated by Chi-square test, the Student t test, Rank-sum test and multiple logistic regression analysis, α=0.05. Results Among92cT1N0M0lung adenocarcinomas, EGFR effective mutation was detected in63patients and non EGFR effective mutation (including EGFR wild type and ineffective mutation) in29patients. Significant differences in sex (P=0.043), age (P=0.002), smoking status (P=0.003), tumor size (P=0.024) and SUVmax (P=0.041) between EGFR effective mutation and non-EGFR effective mutation were observed. Age≥60(OR=4.973,95%CI:1.616～15.307, P=0.005) and tumor diameter≥1.55cm(OR=4.222,95%CI:1.366～13.502,P=0.012)were independent factors of EGFR effective mutation in cT1N0M0lung adenocarcinomas. Conclusion In cT1N0M0lung adenocarcinoma, EGFR effective mutation is associated with female, age≥60, non-smoking, tumor diameter≥1.55cm and SUVmax≥4.05. Patients of cT1N0M0lung adenocarcinomas with these factors may encouraged to have EGFR molecular test after surgical resection for helping to guide tyrosine-kinase inhibitor (TKI) therapies at the time of recurrence or progression. Part VCystic-liked lung adenocarcinoma:demonstration by HRCT and histopathologic correlation[Abstract] Objective To evaluate HRCT features of cystic-liked lung adenocarcinoma and the correlation between HRCT and histopathology, observe the pathological foundation of air-containing space. Methods HRCT and histopathologic findings of cystic-liked lung adenocarcinoma n104patients were nvestigated retrospectively. Image features of both tumor and air-containing space were analyzed. All surgically resected specimens were reviewed. Correlations between image features and histopathologic grades estimated by using the predominant histologic subtypes and differentiation degree was assessed. The formation basis of air-containing space was observed from pathological findings. Results On HRCT, intratumoral necrosis was detected in24cases (23.1%), air-containing space with septa in48cases (46.2%), wall nodule of air-containing space in23cases (22.1%), mixed thick and thin wall of air-containing space in62cases (59.6%). Air-containing space and its wall were observed in74cases on histologic specimen, among which disruption of the alveolar wall by tumor cells was the possible pathological foundation of air-containing space in53(71.6%) cases. Differences of tumor attenuation (P=0.012), intratumoral necrosis (P=0.014) and proportion of thin-wall in air-containing space (P=0.003) among different histopathologic grade were significant. The proportion of thin-wall in air-containing space was negative correlation with histopathologic grade (r=-0.26, P=0.009). Differences of tumor contour (P=0.007), tumor attenuation (P=0.001), intratumoral necrosis (P<0.001), septa in air-containing space (P=0.044) and proportion of thin-wall in air-containing space (P=0.002) among different differentiation degree were significant. The proportion of thin-wall in air-containing space was positive correlation with differentiation degree (r=0.249, P=0.011). Conclusion On HRCT, cystic-liked lung adenocarcinoma may manifest as air-containing space with septa, mixed thin and thick wall, whereas wall nodule of air-containing space and intratumoral necrosis were not common. The image features on HRCT are related with the histopathologic grade and differentiation degree of tumor. Disruption of the alveolar wall by tumor cells maybe the main pathological foundation of air-containing space in cystic-liked lung adenocarcinoma speculated from histologic specimen.