Hisao Asamura

International association for the study of lung cancer/american thoracic society/european respiratory society international multidisciplinary classification of lung adenocarcinoma.

Introduction: Adenocarcinoma is the most common histologic type of lung cancer. To address advances in oncology, molecular biology, pathology, radiology, and surgery of lung adenocarcinoma, an international multidisciplinary classification was sponsored by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society. This new adenocarcinoma classification is needed to provide uniform terminology and diagnostic criteria, especially for bronchioloalveolar carcinoma (BAC), the overall approach to small nonresection cancer specimens, and for multidisciplinary strategic management of tissue for molecular and immunohistochemical studies. Methods: An international core panel of experts representing all three societies was formed with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons. A systematic review was performed under the guidance of the American Thoracic Society Documents Development and Implementation Committee. The search strategy identified 11,368 citations of which 312 articles met specified eligibility criteria and were retrieved for full text review. A series of meetings were held to discuss the development of the new classification, to develop the recommendations, and to write the current document. Recommendations for key questions were graded by strength and quality of the evidence according to the Grades of Recommendation, Assessment, Development, and Evaluation approach. Results: The classification addresses both resection specimens, and small biopsies and cytology. The terms BAC and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced such as adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) for small solitary adenocarcinomas with either pure lepidic growth (AIS) or predominant lepidic growth with ≤5 mm invasion (MIA) to define patients who, if they undergo complete resection, will have 100% or near 100% disease-specific survival, respectively. AIS and MIA are usually nonmucinous but rarely may be mucinous. Invasive adenocarcinomas are classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous BAC), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous BAC), colloid, fetal, and enteric adenocarcinoma. This classification provides guidance for small biopsies and cytology specimens, as approximately 70% of lung cancers are diagnosed in such samples. Non-small cell lung carcinomas (NSCLCs), in patients with advanced-stage disease, are to be classified into more specific types such as adenocarcinoma or squamous cell carcinoma, whenever possible for several reasons: (1) adenocarcinoma or NSCLC not otherwise specified should be tested for epidermal growth factor receptor (EGFR) mutations as the presence of these mutations is predictive of responsiveness to EGFR tyrosine kinase inhibitors, (2) adenocarcinoma histology is a strong predictor for improved outcome with pemetrexed therapy compared with squamous cell carcinoma, and (3) potential life-threatening hemorrhage may occur in patients with squamous cell carcinoma who receive bevacizumab. If the tumor cannot be classified based on light microscopy alone, special studies such as immunohistochemistry and/or mucin stains should be applied to classify the tumor further. Use of the term NSCLC not otherwise specified should be minimized. Conclusions: This new classification strategy is based on a multidisciplinary approach to diagnosis of lung adenocarcinoma that incorporates clinical, molecular, radiologic, and surgical issues, but it is primarily based on histology. This classification is intended to support clinical practice, and research investigation and clinical trials. As EGFR mutation is a validated predictive marker for response and progression-free survival with EGFR tyrosine kinase inhibitors in advanced lung adenocarcinoma, we recommend that patients with advanced adenocarcinomas be tested for EGFR mutation. This has implications for strategic management of tissue, particularly for small biopsies and cytology samples, to maximize high-quality tissue available for molecular studies. Potential impact for tumor, node, and metastasis staging include adjustment of the size T factor according to only the invasive component (1) pathologically in invasive tumors with lepidic areas or (2) radiologically by measuring the solid component of part-solid nodules.

The IASLC Lung Cancer Staging Project: A Proposal for a New International Lymph Node Map in the Forthcoming Seventh Edition of the TNM Classification for Lung Cancer

The accurate assessment of lymph node involvement is an important part of the management of lung cancer. Lymph node “maps” have been used to describe the location of nodal metastases. However, discrepancies in nomenclature among maps used by Asian and Western countries hinder analyses of lung cancer treatment outcome. To achieve uniformity and to promote future analyses of a planned prospective international database, the International Association for the Study of Lung Cancer proposes a new lymph node map which reconciles differences among currently used maps, and provides precise anatomic definitions for all lymph node stations. A method of grouping lymph node stations together into “zones” is also proposed for the purposes of future survival analyses.

Cancer related mutations in NRF2 impair its recognition by Keap1-Cul3 E3 ligase and promote malignancy

The nuclear factor E2-related factor 2 (Nrf2) is a master transcriptional activator of genes encoding numerous cytoprotective enzymes that are induced in response to environmental and endogenously derived oxidative/electrophilic agents. Under normal, nonstressed circumstances, low cellular concentrations of Nrf2 are maintained by proteasomal degradation through a Keap1-Cul3-Roc1-dependent mechanism. A model for Nrf2 activation has been proposed in which two amino-terminal motifs, DLG and ETGE, promote efficient ubiquitination and rapid turnover; known as the two-site substrate recognition/hinge and latch model. Here, we show that in human cancer, somatic mutations occur in the coding region of NRF2, especially among patients with a history of smoking or suffering from squamous cell carcinoma; in the latter case, this leads to poor prognosis. These mutations specifically alter amino acids in the DLG or ETGE motifs, resulting in aberrant cellular accumulation of Nrf2. Mutant Nrf2 cells display constitutive induction of cytoprotective enzymes and drug efflux pumps, which are insensitive to Keap1-mediated regulation. Suppression of Nrf2 protein levels by siRNA knockdown sensitized cancer cells to oxidative stress and chemotherapeutic reagents. Our results strongly support the contention that constitutive Nrf2 activation affords cancer cells with undue protection from their inherently stressed microenvironment and anti-cancer treatments. Hence, inactivation of the Nrf2 pathway may represent a therapeutic strategy to reinforce current treatments for malignancy. Congruously, the present study also provides in vivo validation of the two-site substrate recognition model for Nrf2 activation by the Keap1-Cul3-based E3 ligase.

Neuroendocrine Neoplasms of the Lung: A Prognostic Spectrum

PURPOSE Neuroendocrine (NE) tumors of the lung include typical carcinoid (TC), atypical carcinoid (AC), large-cell NE carcinoma (LCNEC), and small-cell lung carcinoma (SCLC). Their clinicopathologic profiles and relative grade of malignancy have not been defined. PATIENTS AND METHODS From 10 Japanese institutes, 383 surgically resected pulmonary NE tumors were collected. The histologic diagnosis was determined by the consensus of a pathology panel consisting of six expert pathologists as TC, AC, LCNEC, or SCLC on the basis of the WHO classification, and its relationship to clinicopathologic profiles was analyzed. RESULTS Of the 383 tumors, 18 were excluded because of an improper specimen. The pathology panel reviewed the remaining 366 tumors, and a diagnosis of NE tumor was made in 318 patients (87.4%); 55 patients had TC, nine had AC, 141 had LCNEC, and 113 had SCLC. The 5-year survival rates of patients with all stages were as follows: 96.2% for TC, 77.8% for AC, 40.3% for LCNEC, and 35.7% for SCLC. There was significant prognostic difference between TC and AC as well as between AC and LCNEC+SCLC. However, there was no difference between LCNEC and SCLC, and their survival curves were superimposed. The multivariate analysis indicated that histologic type, completeness of resection, symptoms, nodal involvement, and age were significantly prognostic. CONCLUSION The grade of malignancy of NE tumors was upgraded in the following order: TC, AC, LCNEC, and SCLC. No prognostic difference was noted between LCNEC and SCLC. The high-grade NE histology uniformly indicated poor prognosis regardless of its histologic type.

A Japanese Lung Cancer Registry Study: Prognosis of 13,010 Resected Lung Cancers

Purpose: The validation of tumor, node, metastasis staging system in terms of prognosis is an indispensable part of establishing a better staging system in lung cancer. Methods: In 2005, 387 Japanese institutions submitted information regarding the prognosis and clinicopathologic profiles of patients who underwent pulmonary resections for primary lung neoplasms in 1999 to the Japanese Joint Committee of Lung Cancer Registry. The data of 13,010 patients with only lung carcinoma histology (97.6%) were analyzed in terms of prognosis and clinicopathologic characteristics. Results: The 5-year survival rate of the entire group was 61.4%. For the small cell histology (n = 390), the 5-year survival rates according to clinical (c) and pathologic (p) stages were as follows: 58.8% (n = 161) and 58.3% (n = 127) for IA, 58.0% (n = 77) and 60.2% (n = 79) for IB, 47.1% (n = 17) and 40.6% (n = 29) for IIA, 25.3% (n = 38) and 41.1% (n = 29) for IIB, 29.0% (n = 61) and 28.3% (n = 60) for IIIA, 36.3% (n = 19) and 34.6% (n = 40) for IIIB, and 27.8% (n = 12) and 30.8% for IV (n = 13). For the non-small cell histology (n = 12,620), the 5-year survival rates according to c-stage and p-stage were as follows: 77.3% (n = 5642) and 83.9% (n = 4772) for IA, 59.8% (n = 3081) and 66.3% (n = 2629) for IB, 54.1% (n = 205) and 61.0% (n = 361) for IIA, 43.9% (n = 1227) and 47.4% (n = 1330) for IIB, 38.3% (n = 1628) and 32.8% (n = 1862) for IIIA, 32.6% (n = 526) and 29.6% (n = 1108) for IIIB, and 26.5% (n = 198) and 23.1% (n = 375) for IV. Adenocarcinoma, female gender, and age less than 50 years were significant favorable prognostic factors. Conclusion: This large registry study provides benchmark prognostic statistics for lung cancer. The prognostic difference between stages IB and IIA was small despite different stages. Otherwise, the present tumor, node, metastasis staging system well characterizes the stage-specific prognoses.

Prognosis and survival after resection for bronchogenic carcinoma based on the 1997 TNM-staging classification: the Japanese experience

BACKGROUND A new TNM staging system was proposed, and the previous system was revised in 1997. METHODS To evaluate the new TNM staging system for lung cancer, records of 3,043 lung cancer patients who underwent pulmonary resection at the National Cancer Center Hospital, Tokyo, were analyzed. RESULTS With regard to clinical stages, 3 patients had occult carcinoma; 786 patients had stage IA disease; 759 patients, stage IB; 54 patients, stage IIA; 469 patients, stage IIB; 582 patients, stage IIIA; 211 patients, stage IIIB; and 179 patients, stage IV. The 5-year survival rates for the respective stages were 70.8% for stage IA, 44.0% for stage IB, 41.1% for stage IIA, 36.9% for stage IIB, 22.7% for stage IIIA, 20.1% for stage IIIB, and 21.6% for stage IV. In terms of postoperative stages, 7 patients were classified in stage 0, 610 in stage IA, 506 in stage IB, 114 in stage IIA, 432 in stage IIB, 702 in stage IIIA, 448 in stage IIIB, and 224 in stage IV. The 5-year survival rates were as follows: stage IA, 79.0%; stage IB, 59.7%; stage IIA, 56.9%; stage IIB, 45.0%; stage IIIA, 23.6%; stage IIIB, 16.5%; and stage IV, 5.1%. CONCLUSIONS In the clinical stage, there were significant prognostic differences between stage IA and stage IB, stage IIB and IIIA, and stage IIIA and stage IIIB, but there was no significant difference in 5-year survival rates between stage IB and stage IIA, stage IIA, and IIB, and stage IIIB and stage IV. In the postoperative stage, there were significant differences in 5-year survival rates between each stage except for stage IB and stage IIA.

Pulmonary resection for metastatic colorectal cancer: Experiences with 159 patients ☆ ☆☆ ★ ★★

We reviewed the clinical courses of 159 patients between February 1967 and May 1995 for the purpose of examining the survival of patients who had pulmonary resection for metastatic colorectal cancer. The cumulative survivals at 5 years and 10 years were 40.5% and 27.7%, respectively. Fifteen patients (10%) were alive more than 10 years after the thoracotomy without any evidence of recurrence. The cumulative survival at 5 years for 39 patients who had hepatic metastases before thoracotomy was 33%. There was a statistically significant difference in survival between patients with extrapulmonary metastases and those with only intrapulmonary metastases before thoracotomy. The number of pulmonary metastases and the presence of hilar or mediastinal lymph node metastases affected postthoracotomy survival. There was no significant difference in survival on the basis of sex, age, location of the primary cancer, size of the pulmonary tumors, mode of operation, or disease-free interval. Surgical treatment for pulmonary metastases from colorectal cancer in selected patients, even those who had hepatic metastases before thoracotomy, might improve prognosis.

Comprehensive histologic analysis of ALK-rearranged lung carcinomas.

A subset (1% to 5%) of non-small-cell lung carcinomas harbors the EML4-ALK fusion gene. Data from previous studies on the histomorphology of ALK-rearranged lung cancer are inconsistent, and the specific histologic parameters that characterize this subset and how accurately such parameters predict underlying ALK abnormality remain uncertain. To answer these questions, we performed a comprehensive histologic analysis of 54 surgically resected, extensively sampled ALK-rearranged lung carcinomas and compared them with 100 consecutive resections of ALK-wild-type lung cancers. All 54 cases showed at least a focal adenocarcinoma component, and 3 and 2 cases had additional squamous and sarcomatoid differentiation, respectively. Solid or acinar growth pattern, cribriform structure, presence of mucous cells (signet-ring cells or goblet cells), abundant extracellular mucus, lack of lepidic growth, and lack of significant nuclear pleomorphism were more common in ALK-positive cancers. Two recognizable constellations of findings, a solid signet-ring cell pattern and a mucinous cribriform pattern, were present at least focally in the majority (78%) of ALK-positive tumors, but were rare (1%) in ALK-negative tumors. Multivariate analysis showed that a combination of these 2 patterns was the most powerful histologic indicator of ALK rearrangement. Characteristic histologies were present both in primary sites and in metastases. Thus, histologic findings may help to identify cases for ALK testing. However, none of the histologic parameters were completely sensitive or specific to ALK rearrangement, and histomorphology should not replace confirmatory molecular or immunohistochemical studies. ALK-positive cancers commonly showed coexpression of thyroid transcription factor-1 and p63, and its significance is currently unclear.

A review of 79 thymomas: modification of staging system and reappraisal of conventional division into invasive and non-invasive thymoma.

A clinicopathological study of surgically resected thymomas was performed using Masaokas staging and modified Masaokas staging systems, and the utility of these two staging systems was compared. The modification enabled adjustment for the disproportion in the number of cases between Stage I and Stage II. Analysis of survival rates, according to the tumor stage, indicated that the old classification should be reappraised, that is, division into non‐invasive and invasive thymomas, although staging may contribute to the indication for postoperative radiotherapy, especially for Stage II disease. Analysis of the cases showed a wide spectrum of aggressiveness, varying from cases showing slow progression with a relatively favorable prognosis, such as the spindle cell type, to cases with rapid progression leading to tumor death in a relatively short time, such as the epithelial cell predominant and polygonal cell type. The pathological stage at the time of first surgical resectlon would reflect the degree of aggressiveness of thymoma in many instances. Therefore, not only staging the tumor extent but also grading of its aggressiveness are needed in order to predict the prognosis of patients with thymoma. For the latter, histology and cytopathology are helpful.

A Prospective Radiological Study of Thin-Section Computed Tomography to Predict Pathological Noninvasiveness in Peripheral Clinical IA Lung Cancer (Japan Clinical Oncology Group 0201)

Purpose: Pathological noninvasiveness needs to be precisely predicted in preoperative radiological examinations of patients with early lung cancer for the application of limited surgery. Patients and Methods: Patients with clinical T1N0M0 peripheral lung cancer were recruited. Radiological findings of the main tumor were evaluated as to ground-glass opacity with thin-section computed tomography. The primary end point was specificity, i.e., the proportion of patients with radiologically diagnosed invasive lung cancer to patients with pathologically diagnosed invasive lung cancer. The precision-based planned sample size was 450. We expected that the lower limit of the 95% confidence interval (CI) for specificity should be satisfied in ≥97% of patients. Results: We enrolled 811 patients from 31 institutions between December 2002 and May 2004. The primary end point was evaluated in 545 patients. The specificity and sensitivity for the diagnosis of pathologically diagnosed invasive cancer were 96.4% (161/167, 95% CI: 92.3–98.7%) and 30.4% (115/378, 95% CI: 25.8–35.3%), respectively, i.e., a negative result. Nevertheless, the specificity for lung adenocarcinoma ≤2.0 cm with ≤0.25 consolidation to the maximum tumor diameter was 98.7% (95% CI: 93.2–100.0%), and this criterion could be used to radiologically define early adenocarcinoma of the lung. Conclusions: Although our predetermined criterion for specificity was not statistically confirmed, radiological diagnosis of noninvasive lung cancer with a thin-section computed tomography scan corresponded well with pathological invasiveness. Radiological noninvasive peripheral lung adenocarcinoma could be defined as an adenocarcinoma ≤2.0 cm with ≤0.25 consolidation.