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Objectives: Micropapillary (MIP) and solid (SOL) subtypes of early-stage lung adenocarcinomas are associated with lymph node metastasis and local recurrence after limited resection. Preoperative identification of these components may influence the decisions of treatment strategy, additional lymph node evaluation, indication for limited resection, and extent of lymph node dissection. However, conventional biopsy specimens are insufficient for identifying these subtypes, especially MIP components. Cryobiopsy can collect larger tissue samples with fewer crush artifacts than conventional forceps biopsy, which would be helpful for detecting MIP/SOL components. Thus, this study aimed to analyze the feasibility of using cryobiopsy for MIP/SOL subtype detection., Material and Methods: Consecutive patients who underwent surgery for clinical IA lung cancer following a preoperative diagnosis of adenocarcinoma by cryobiopsy at our institution between October 2017 and July 2019 were retrospectively examined. The concordance rate of MIP/SOL subtypes between the specimens obtained by cryobiopsy and surgery was investigated., Results: In total, 115 patients were evaluated. There were 26 (22.6%) and 14 (12.2%) patients with MIP and SOL subtypes, respectively. For concordance of MIP/SOL subtypes, the sensitivity was 65.7% (95% confidence interval [CI]: 57.7-65.7%). For the primary or secondary predominant patterns, a more satisfactory concordance rate of 72.2% (95% CI: 52.6-86.2%) was obtained. On assessing each subtype, high sensitivity was noted in SOL-predominant patterns (85.7%, 95% CI: 56.5%-96.0%) and MIP-secondary predominant patterns (83.3%, 95% CI: 45.8-97.0%). However, SOL-secondary predominant patterns revealed low sensitivity (0%, 95% CI, 0-38.2%). Overall, the MIP subtypes had higher sensitivity than the SOL subtypes (65.4% vs. 50.0%)., Conclusion: Cryobiopsy could be reliable for identifying MIP/SOL components, especially the MIP component, in clinical stage IA adenocarcinomas., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objectives: The aim of this study was to evaluate the impact of the preoperative body mass index (BMI) on the postoperative outcomes in patients with completely resected non-small cell lung cancer (NSCLC)., Materials and Methods: The data of patients with NSCLC in whom R0 resection was achieved were extracted from the database of NSCLC samples accumulated by the Japanese Joint Committee of Lung Cancer Registry in the year 2010, and the surgical outcomes including postoperative morbidity, mortality and the prognosis, were evaluated., Results: Among 18,978 registered lung cancer cases, 16,509 patients (9996 men and 6513 women) were extracted. The median of age was 69 years old, and the histologic types included adenocarcinoma (n = 12,029), squamous cell carcinoma (n = 3286), large-cell carcinoma (n = 488) and others. The patients were divided into three groups according to their BMI: normal (BMI 18.5 to <25), underweight (BMI < 18.5) and overweight (BMI ≥ 25). Multivariate logistic regression analyses of factors associated with postoperative morbidity and mortality showed no significant differences among the three groups. In comparison to the normal group, the overall survival (OS) of the underweight group was significantly worse (p < 0.001) while that of the overweight group was marginally better (p = 0.075). A multivariate analysis of factors associated with OS showed that in addition to the age, sex and clinical stage, the preoperative BMI (underweight group vs. normal group: hazard ratio [HR] 1.417 [95% confidence interval {CI}: 1.278-1.572, p < 0.001], overweight group vs. normal group: HR 0.883 [95% CI: 0.806-0.967, p = 0.007]) was an independent prognostic factor. A multivariate analysis for the disease-free survival (DFS) also showed the preoperative BMI to be an independent significant prognostic factor., Conclusions: The preoperative BMI is an independent prognostic factor in patients with completely resected NSCLC. A low preoperative BMI was associated with significantly poor survival in Japan., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Introduction: The majority of pulmonary carcinoid (PC) tumors can be cured by surgical resection alone, but a significant proportion of patients experience recurrence. As PC is insensitive to conventional chemotherapy, further clarification of the molecular mechanisms of metastasis is needed in order to develop targeted therapeutics., Methods: We performed comprehensive whole-exome sequencing (WES) of primary tumors and corresponding normal lung tissues from 14 PC patients (including 4 patients who developed postsurgical distant metastasis) and RNA sequencing of primary tumors from 6 PC patients (including 4 patients who developed postsurgical distant metastasis). Exon array-based gene expression analysis was performed in 25 cases of PC., Results: We identified a total of 139 alterations in 136 genes. MUC6 and SPTA1 were recurrently mutated at a frequency of 21% (3/14) and 14% (2/14), respectively. Mucin protein family genes including MUC2, MUC4 and MUC6 were mutated in a mutually exclusive manner in 36% (5/14). Pathway analysis of the mutated genes revealed enrichment of genes involved in mitogen-activated protein kinase (MAPK) signaling, regulation of the actin cytoskeleton and focal adhesion, and transforming growth factor (TGF)-β signaling. RNA sequencing revealed a total of 8 novel fusion transcripts including one derived from a chromosomal translocation between the TRIB2 and PRKCE genes. All of the 8 fusion genes were detected in primary PCs that had developed metastasis after surgical resection. We identified 14 genes (DENND1B, GRID1, CLMN, DENND1B, NRP1, SEL1L3, C5orf13, TNFRSF21, TES, STK39, MTHFD2, OPN3, MET, and HIST1H3C) up-regulated in 5 PCs that had relapsed after surgical resection., Conclusions: In this study we identified novel somatic mutations and chromosomal rearrangements in PC by examining clinically aggressive cases that had developed postsurgical metastasis. It will be essential to validate the clinical significance of these genetic changes in a larger independent patient cohort., Competing Interests: Declaration of Competing Interest The authors have no potential conflicts of interest to disclose., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Invasion is a crucial indicator of the prognosis in lung adenocarcinoma. The 2015 WHO classification of lung tumors defined invasion of adenocarcinoma mainly by the presence of non-lepidic histological subtypes including papillary, acinar, micropapillary and solid patterns, and the presence of cancer-associated active fibroblasts (CAF). In this study, we focused specifically on early-stage lepidic adenocarcinoma with CAF to evaluate its prognostic significance., Methods: We included 1032 resected cases of lung adenocarcinoma, which consisted of pathological stage IA invasive cancer and adenocarcinoma in situ (AIS). Invasive adenocarcinoma was classified into two subgroups according to the type of invasion, INV-1 and INV-2. We defined INV-1 as adenocarcinoma of a non-lepidic histological subtype with or without CAF, and INV-2 as lepidic adenocarcinoma with CAF. The clinicopathological characteristics and prognosis were retrospectively analyzed., Results: Included cases were classified into 696 (67.4 %) INV-1, 170 (16.5 %) INV-2, and 166 (16.1 %) AIS. The estimated 5-year recurrence-free probabilities of INV-1, INV-2, and AIS were 92.9 %, 100 %, and 100 %, respectively (p <  0.001). Although there were significant differences between INV-1 and INV-2 in terms of gender (more males in INV-1, p =  0.039), smoking habit (more smokers in INV-1, p =  0.046), and lymphovascular invasion (more invasion in INV-1, p <  0.001), there was no difference between AIS and INV-2., Conclusion: The presence of CAF is not always associated with a worse prognosis, and therefore it does not seem appropriate to include the presence of CAF alone in diagnostic criteria for invasion in early-stage lung adenocarcinoma., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objectives: Over the past decade, the biological and clinical characteristics of lung cancer with epidermal growth factor receptor (EGFR) mutation have been well studied. However, most studies have focused on advanced inoperable cancer, and not on resected early-stage lung adenocarcinoma. We aimed to elucidate the differences in the clinicopathological characteristics and postoperative prognosis according to the EGFR mutation status in early-stage lung adenocarcinoma., Materials and Methods: We retrospectively collected clinical and pathological data from 369 patients with pathological stage I or II lung adenocarcinoma who underwent complete resection. Clinicopathological characteristics and postoperative prognosis were compared depending on the EGFR mutation status, using the Chi-squared test and the log-rank test, respectively., Results and Conclusion: Of the 369 patients, 160 (43.3%) had EGFR mutation, of which 64 (40.0%) were exon 19 deletion (Del-19) and 90 (56.3%) were exon 21 point mutation L858R. Although there was no difference in overall survival (OS) between patients with and without EGFR mutation (p=0.086), tumors with EGFR mutation were associated with a lower consolidation to tumor ratio (CTR) (p <0.001) and a higher incidence of a lepidic growth pattern by pathological evaluation (p <0.001) compared to those without EGFR mutation. Among tumors with EGFR mutation, there was no difference in OS (p=0.140) between Del-19 and L858R. Tumors with L858R were associated with a lower CTR (p=0.046), and tended to have a higher incidence of a lepidic growth pattern by pathological evaluation (p=0.073) compared to those with Del-19. In conclusion, although EGFR mutation status was not a prognostic indicator after surgery in early-stage lung adenocarcinoma, L858R and Del-19 had different radiological and pathological features., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objectives: The precise and rapid diagnosis of the presence or absence of lymph node (LN) metastasis is essential for deciding upon an appropriate therapeutic strategy for patients with non-small cell lung cancer (NSCLC). We conducted a prospective multicenter clinical trial in Japan to evaluate a rapid, automated and objective assay system, the one-step nucleic acid amplification (OSNA) assay (Sysmex Corp), which targets cytokeratin 19 mRNA, to detect LN metastasis of NSCLC., Materials and Methods: A total of 410 Lymph nodes (LNs) from 111 patients with clinical stage IB to IIIA NSCLC who underwent lung resection with LN dissection were included in this study. The LNs were divided into 4 blocks and examined by either the OSNA assay or a 3-level histological examination. The results of each method were compared and further analyses were performed for discordant cases. The primary endpoint was a concordance rate of more than 85% between the two methods., Results: The concordance rate between the two methods was 92.7% (95% CI, 89.7-95.0%), with a sensitivity of 79.7% (95% CI, 67.2-89.0%). Discordant results were observed in 30 LNs (5.8%), and were mainly due to a tissue allocation bias and/or contamination by CK19-expressing alveolar cells in LNs., Conclusion: The OSNA assay gave a diagnosis that was as accurate as a 3-level histological examination, which is more detailed than a histological examination in routine clinical practice. The OSNA assay might be useful in intraoperative decision-making in personalized lung cancer surgery based on the LN status., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Objectives: Tumor hypoxia is believed to have a strong correlation with the resistance to chemoradiotherapy. Noninvasive evaluation of hypoxic status in tumors using molecular imaging has the potential to characterize the tumor aggressiveness. We evaluated the clinical usefulness of newly-developed tumor hypoxic positron emission tomography (PET) tracers in localized non-small-cell lung cancer (NSCLC)., Patients and Methods: Forty-seven patients with localized NSCLC received either or both hypoxic PETs using the tracers: (18)F-fluoroazomycin arabinoside ((18)F-FAZA) (n=45) and/or (62)Cu-diacetyl-bis (N4)-methylsemithiocarbazone ((62)Cu-ATSM) (n=22). All received (18)F-fluorodeoxyglucose ((18)F-FDG) PET tracer (n=47). We examined the correlation between uptake of three PET tracers and clinicopathological factors, and evaluated their impacts on survival after treatment retrospectively., Results: A couple of commonly-identified unfavorable factors such as presence of vascular invasion and pleural invasion was significantly correlated with higher uptake of these hypoxic agents as well as that of (18)F-FDG. Larger tumor diameter, high neutrophil-to-lymphocyte ratio and advanced pathological stage were also associated with accumulation of hypoxic PETs ((18)F-FAZA, p<0.01; (62)Cu-ATSM, p<0.04), but not with that of (18)F-FDG. The patients with a higher accumulation had significantly poorer overall survival [(18)F-FAZA, HR (hazard ratio), 9.50, p<0.01; (62)Cu-ATSM, HR, 4.06, p<0.05] and progression free survival ((18)F-FAZA, HR, 5.28, p<0.01, (62)Cu-ATSM, HR, 2.72, p<0.05)., Conclusion: Both (18)F-FAZA and (62)Cu-ATSM PET provide useful information regarding tumor aggressiveness and prediction of survival among NSCLC patients. We believe these hypoxic PETs could contribute to the establishment of the optimally individualized treatment of NSCLC., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Dysregulation of HER2 signaling pathways results in tumor progression in several types of carcinomas. The aim of the current study is to identify clinicopathological characteristics of HER2-mutated non-small cell lung carcinomas (NSCLCs) in conjunction with HER2 protein expression, gene amplification, and phosphorylation., Patients and Methods: We investigated 1275 patients including 1055 adenocarcinomas (ADCs), 146 squamous cell carcinomas, 2 large cell carcinomas, 8 sarcomatoid carcinomas, and 64 adenosquamous carcinomas. High-resolution melting analysis of HER2 hot spot inflame deletion mutations, chromogenic in situ hybridization for HER2 amplification, and immunostaining of wild-type and phosphorylated HER2 was performed., Results: HER2 mutations were detected in 46 (3.6%) of the NSCLCs, with mutations only present in the ADC. When analyzing ADC cases alone, the incidence of HER2 mutation was increased to 4.3%. All HER2-mutated tumors were negative for other driver gene alterations. HER2 mutation status correlated with never-smoker status and patients with smaller tumor size. HER2 amplifications were also identified in approximately half of the tumors with HER2 mutations. The overall survival rate was not significantly different between patients without and with HER2 mutations. When analyzing only invasive ADCs, HER2 mutation status was an independent factor for an unfavorable outcome. Amongst the 46 patients harboring HER2 mutations, univariate and multivariate analysis revealed that HER2 amplification was an unfavorable prognostic factor, while HER2 phosphorylation was a favorable prognostic factor., Conclusions: HER2 mutations were observed in 3.6% of NSCLCs, particularly in younger patients, those with no history of smoking, and those with small tumors. Amongst the patients with HER2 mutations, HER2 amplification and phosphorylation were independent prognostic factors., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: The use of one-step nucleic acid amplification (OSNA), which allows for the rapid intraoperative detection of lymph node (LN) metastasis, is becoming more widely accepted in breast cancer. To provide basic data for the development of this method for lung tumors, we conducted a large-scale investigation of cytokeratin (CK) 19 expression in thoracic tumors., Patients and Methods: We examined CK19 expression in specimens from a total of 801 surgically resected samples of primary lung adenocarcinoma (ADC), squamous cell carcinoma (SQC), large-cell carcinoma (LCC), pleomorphic carcinoma (PC), large cell neuroendocrine carcinoma (LCNEC), small cell carcinoma (SCC), and carcinoid tumor (CT) as well as pleural malignant mesothelioma and lung metastatic deposits from breast cancer using tissue microarrays (TMAs) and whole sections. We also compared the CK19 expression status between primary sites and LN metastatic deposits., Results: The overall rate of CK19 expression as observed on TMAs and whole sections in the 801 analyzed cases was 88.0%. CK19 expression was detected in 94.6% of ADCs, 93.6% of SQCs, 54.5% of LCCs, 54.8% of PCs, 77.4% of LCNECs, 31.8% of SCCs, 34.0% of CTs, and 92.9% of malignant mesotheliomas. Expression of CK19 was also detected in 90.9% of lung metastatic deposits from breast carcinomas. CK19 expression was maintained between CK19-positive primary sites and the corresponding LN metastatic deposits. Of note, a portion of CK19-negative primary tumors showed upregulation of CK19 protein expression in LN metastases., Conclusions: Most thoracic tumors, except for PCs, CTs, and SCCs, were positive for CK19. We also found that CK19 expression was maintained between CK19-positive primary tumors and the corresponding LN metastatic deposits. These results may be useful in the development of the OSNA method for the intraoperative detection of LN metastasis in non-small cell lung cancer (NSCLC)., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: Lung adenocarcinoma with morule-like components is an unusual variant of lung adenocarcinoma, comprising uniform, tightly packed spindle-shaped cells, which fill the lumen of the glandular structures of the carcinoma. The aim of the study was to outline the clinicopathologic features of this variant., Patients and Methods: We examined a series of 904 surgically resected adenocarcinomas. We defined morule-like components as small buds of spindle-cell proliferation in the tumor lumen of the glandular structures of the carcinoma and calculated their proportion of total tumor mass. Targeted genotyping was performed for KRAS, EGFR, HER2, and BRAF. ALK rearrangements were analyzed immunohistochemically. Immunopositive cases were confirmed using RT-PCR and/or FISH., Results: We detected 17 cases of adenocarcinoma with morule-like components. This variant, representing only 1.9% was associated with unfavorable outcomes and a mutation in the EGFR. Histologic examination revealed adenocarcinoma with morule-like components accounting for 5-50% of tumors. Among the morule-like components, 10 (58.8%) of the 17 samples showed intracytoplasmic lumina formation containing eosinophilic mucinous material. The presence of micropapillary components in adenocarcinoma with morule-like components suggests that morule-like components could be merely excessive growth of the micropapillary pattern. However, our results indicated no statistical differences in the MIB-1 indices of the morule-like components and the adjacent tumor components or the micropapillary components. The univariate and multivariate analyses revealed a correlation between the presence of a morule-like components and an unfavorable outcome., Conclusions: Our study clearly indicated that adenocarcinoma with morule-like components is distinct unfavorable prognostic and predictor for EGFR mutation., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Objective: The clinicopathological characteristics and surgical results of young lung cancer patients were investigated., Materials and Methods: Seven hundred and four (6.0%) patients with lung cancer, aged up to 50 years, were enrolled from among the 11,663 patients registered in the Japanese Lung Cancer Registry Study 2004, and their clinical data were compared with those of 10,959 patients older than 50 years. This epidemiological study is based on the single year registration of surgically treated patients in the major institutes in Japan., Results: The 5-year overall survival rate (5Y-OS) and the 5-year lung cancer-related survival rate was 79.2%/69.0% (p<0.001) and 81.3%/76.6% (p=0.005) in the young/old groups, respectively. In the young/old groups, lobectomy and pneumonectomy was performed in 76.9%/78.0% and 5.7%/3.2%, respectively; adjuvant therapies were given preoperatively in 10.4%/4.7% (p<0.001) and postoperatively in 31.4%/24.5% (p<0.001). The proportions of patients with p-stage IIIA (18.2%) and adenocarcinoma histology (78.7%) were higher in the young group. The 5Y-OS was 94.8%/86.2% for p-stage IA (p<0.001), 87.0%/73.2% for p-stage IB (p=0.001), 61.0%/61.6% for p-stage IIA (p=0.595), 71.0%/48.4% for p-stage IIB (p=0.003), 49.6%/39.4% for p-stage IIIA (p=0.020), and 80.0%/24.8% for p-stage IIIB (p=0.012); it was 83.5%/80.7% for females (p=0.106) and 75.1%/62.3% for males (p<0.001) in the young/old groups. The postoperative survival was significantly better with all operative procedures in the young group. The 5Y-OS after recurrence was 17.9%/13.4% in the young/old groups (p=0.016). In the young group, the 5Y-OS was better in females (83.5%) than in males (75.1%, p=0.002), and for patients with adenocarcinoma (80.3%) than for those with squamous cell carcinoma (68.5%, p=0.013). Age up to 50 years was identified as an independent better prognostic factor on multivariate analysis., Conclusions: The postoperative survival in lung cancer patients aged up to 50 years was better than that in patients older than 50 years., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Background: The present study aimed to determine the ability of the revised International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) classification of lung adenocarcinoma to predict patient survivals and driver gene alterations., Patients and Methods: A reclassification of 904 surgically resected adenocarcinomas was performed. The results were statistically analyzed to examine the correlation between the classification and overall survival (OS) using Cox regression analyses, and integrated discrimination improvement (IDI) analyses., Results: The 5-year OS rates for adenocarcinomas in situ (AIS) or minimally invasive adenocarcinoma (MIA) were 98%. Five-year OS rates of Lepidic-, acinar-, papillary-, micropapillary-, and solid-predominant adenocarcinomas was 93%, 67%, 74%, 62%, and 58%, respectively. The IDI estimates revealed that classification of ADC into the 7 subgroups had a higher estimated (0.0175) than did the combined histological grouping (AIS + MIA, lepidic + acinar + papillary, micropapillary + solid + others) (0.0111). Epidermal growth factor receptor mutations, KRAS gene mutations, and anaplastic lymphoma kinase gene alterations were statistically prevalent in papillary-predominant (P = 0.00001), invasive mucinous (P = 0.00001), and micropapillary- and acinar-predominant (P = 0.00001) adenocarcinomas, respectively., Conclusions: The new classification reflects disease prognosis, and was also associated with driver gene alterations., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Introduction: Among the mutations of epidermal growth factor receptor (EGFR), deletions in exon 19 (DEL), and point mutations in exon 21 (L858R) predict the response to EGFR-tyrosine kinase inhibitors (TKIs) in primary lung adenocarcinoma. The ability to detecting such mutations using immunohistochemistry (IHC) would be advantageous., Methods: The molecular-based and IHC-based EGFR mutations were analyzed in 577 lung adenocarcinomas using high resolution melting analysis (HRMA) and 2 mutation-specific antibodies, respectively., Results: In the molecular-based analyses, DEL was detected in 135 cases (23%), and L858R was detected in 172 cases (30%). In the IHC-based analyses, a positive reaction was detected in 59 cases (10%) for the DEL-specific antibody, and in 139 cases (24%) for the L858R-specific antibody. With the molecular-based results set as the gold standard, the sensitivity and specificity of the DEL-specific antibody were 42.2% and 99.5%, respectively, while the sensitivity and specificity of the L858R-specific antibody were 75.6% and 97.8%, respectively. The antibody specificities improved when the threshold for the mutation-positive reactions was set as >50% of immunopositive tumor cells. The significant predictors of the clinical response to EGFR-TKI were molecular-based EGFR mutations (p<0.001) and IHC-based EGFR mutations (p=0.001). However, a multivariate analysis revealed that only molecular-based EGFR mutations were significantly correlated with the clinical response (p<0.001)., Conclusions: Mutation-specific antibodies demonstrated extremely high specificities, but their sensitivities were not higher than those of molecular-based analyses. However, IHC should be performed before a molecular-based analysis, because it is more cost-effective and can effectively select candidates for EGFR-TKI therapy., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Pulmonary heterotopic ossification is an unusual event. The relationship between ossification and lung carcinoma is unclear. The present study analyzed clinicopathological features of primary lung carcinoma with heterotopic ossification. We reviewed 2269 surgically resected primary lung carcinomas and identified 33 with heterotopic ossification, including 15 cases with intratumoral heterotopic ossification (IHO) and 18 cases with extratumoral heterotopic ossification (EHO). All cases with IHO were adenocarcinomas and 10 of 15 (66.6%) cases had confirmed positive mucin staining in the tumor cells. Cases with EHO could be divided into three patterns, and each pattern is potentially associated with the background conditions of lung parenchyma. Immunohistochemistry, BMP-2 production was present in 13 of 15 (86.7%) cases with IHO, although, only 4 of 17 (23.5%) cases with EHO. A prognostic analysis revealed no statistically significant difference to be observed between adenocarcinomas with IHO and without IHO. The present study suggested that IHO associated with adenocarcinomas and BMP-2 production in the tumor cells, whereas EHO was not associated with the biology of the carcinoma.

Objective: Although the incidence of peripheral squamous cell carcinomas (SqCCs) of the lung has increased over recent years, histologic prognostic factors for small peripheral SqCCs have not been well established. The aim of this study is to identify clinicopathologic prognostic factors., Materials and Methods: We evaluated various clinicopathologic parameters in 101 patients with peripheral lung SqCCs (defined as tumors located in or more peripheral to the fourth branching bronchus), measuring < or = 30 mm in diameter., Results: Multivariate analysis showed that the size of the minimal tumor nest (MTN), a background of usual interstitial pneumonia (UIP) and lymph node metastasis were significant prognostic factors. MTN sizes were defined as large (>6 tumor cells), small (2-5 tumor cells) or single cell. The 5-year disease-free survival rate was significantly worse in patients with single cell nests (50 patients, 69.5%) than in those with small nests (42 patients, 94.1%) (P = 0.0035, log rank test). The MTN size had a significant impact on survival in patients with pathologic stage IA disease and tumors < or = 20 mm in diameter. A background of UIP, which correlated with the presence of a single cell invasive component and pleural involvement, was also a poor prognostic factor, suggesting that peripheral SqCC in UIP is highly malignant even if the tumor is small., Conclusion: The MTN size is a useful prognostic factor for small peripheral SqCCs. Tumors with a single cell invasive component appear to be highly malignant, and should be distinguished from invasive cancers with a low malignant potential (tumors with large or small tumor nest components).

For the scheduled future revision of the TNM staging system for lung cancer, it is important that the present 1997 version be evaluated in a large population. In 2001, the Japanese Joint Committee of Lung Cancer Registry sent a questionnaire to 320 Japanese institutions regarding the prognosis and clinicopathological profiles of patients who underwent the resection for primary lung neoplasms in 1994. We compiled the data for 7408 patients from 303 institutions (94.7%). Among these, 6644 patients with non-small cell histology were studied in terms of prognosis. The 5-year survival rate of the entire group was 52.6%. The 5-year survival rates by clinical (c-) stage were as follows: 72.1% for IA (n = 2423), 49.9% for IB (n = 1542), 48.7% for IIA (n = 150), 40.6% for IIB (n = 746), 35.8% for IIIA (n = 1270), 28.0% for IIIB (n = 366) and 20.8% for IV (n = 147). The difference in prognosis between neighboring stages was significant except for between IB and IIA and between IIIB and IV. The 5-year survival rates by pathological (p-) stage were as follows: 79.5% for IA (n = 2009), 60.1% for IB (n = 1418), 59.9% for IIA (n = 232), 42.2% for IIB (n = 757), 29.8% for IIIA (n = 1250), 19.3% for IIIB (n = 719) and 20.0% for IV (n = 259). The difference in prognosis between neighboring stages was significant except for between IB and IIA and between IIIB and IV. The survival curves of stages IB and IIA were almost superimposed in both c- and p-settings. These findings indicated that the present stages IB and IIA should be merged into the same stage category. Otherwise, the present TNM staging system seemed to well characterize the stage-specific prognosis in non-small cell lung cancer. The future revision should focus on the subdivision of stages I and II.

A hypothesis of multistep carcinogenesis of lung adenocarcinoma from atypical adenomatous hyperplasia (AAH) to invasive adenocarcinoma through bronchioloalveolar carcinoma (BAC) has been proposed. However, the genetic alterations that play a role during these processes are not yet clear. Recently, somatic mutations of the epidermal growth factor receptor (EGFR) gene were found in lung adenocarcinoma. We examined the status of EGFR mutations in AAH and BAC to elucidate the role they play during multistage of lung adenocarcinoma. We found somatic EGFR mutations in 3% (1/35) of AAH, 10.8% (4/37) of BAC and 41.9% (13/31) of invasive adenocarcinoma. Sixteen of 18 EGFR mutations were found in exon 19 and two were in exon 21. Among the 16 EGFR mutations in exon 19, 13 were deletions of 15bp and one was an insertion/duplication of 18bp. Mutations of the K-ras gene were detected in 26.7% (8/30) of AAH, 16.7% (5/30) of BAC and 10% (3/30) of invasive adenocarcinoma. None of the tumors with EGFR mutations had K-ras mutation simultaneously. Patients who had invasive adenocarcinoma with EGFR mutations were younger than those without mutations (60.6 versus 67.4 years, p=0.03). These results suggest that tumors with EGFR mutations may progress more rapidly and develop into invasive cancer faster than those without mutations. Alternatively it is also possible that some invasive adenocarcinomas with EGFR mutations may not follow the AAH-adenocarcinoma sequence. We analyzed 24 patients with multiple lung lesions and 13 patients had at least one lesion that had either an EGFR or K-ras mutation. In all cases each lesion had a different mutation status. This finding suggests that the genetic alterations responsible for the development of lung adenocarcinoma occur randomly even under exposure to the same carcinogen.

Background: The efficacy of chemotherapy in patients with large cell neuroendocrine carcinoma of the lung (LCNEC) remains unclear., Methods: Patients with LCNEC who received cisplatin-based chemotherapy were identified by reviewing 567 autopsied and 2790 surgically resected lung cancer patients. The clinical characteristics and objective responses to chemotherapy in these patients were analyzed., Results: Overall, 20 cases of LCNEC were identified, including stage IIIA (n=3), stage IIIB (n=6), stage IV (n=6) and postoperative recurrence (n=5) cases. Six patients had received prior chemotherapy, and 14 were chemo-naive patients. The patients had received a combination of cisplatin and etoposide (n=9), cisplatin, vindesine and mitomycin (n=6), cisplatin and vindesine (n=4), or cisplatin alone (n=1). One patient showed complete response and nine showed partial response, yielding an objective response rate of 50%. The response rate did not differ between patients with the initial diagnosis of SCLC and those with the initial diagnosis of NSCLC, however, the response rate in chemo-naive patients (64%) was significantly different from that in previously treated patients (17%)., Conclusions: Our results suggest that the response rate of LCNEC to cisplatin-based chemotherapy was comparable to that of SCLC.

To evaluate the diagnostic value of video-assisted thoracic surgery (VATS), VATS exploration was performed in 135 patients with histologically/cytologically proven or suspected lung cancer. In 31 patients with pulmonary nodules suspected to be lung cancer, VATS exploration was intended to determine their histology by wedge resection. A histological diagnosis was made in all of the patients: 12 lung cancers (38.7%), 12 inflammatory granulomas (38.7%), four hamartomas (12.9%), and three others. VATS exploration (staging) was performed in 116 surgical candidates with documented lung cancer, including the 12 patients diagnosed by VATS wedge resection. Inoperable factors were demonstrated by this procedure in five patients (4.3%): malignant effusion without dissemination in three, malignant effusion with extensive dissemination in one, and extensive dissemination without effusion in one. Furthermore, N2 nodal metastasis at Botallo's ligament was demonstrated by this procedure in two patients, which met the eligibility criteria for a clinical study. Although the documented number of patients was relatively small, VATS exploration obviated the need for painful thoracotomy, selecting better treatment and for evaluating eligibility criteria for prospective clinical trials. The results suggest that this procedure is useful in candidates for lung cancer surgery.