Anatomy, Biology and Concepts, Pertaining to Lung Cancer Stage Classification

The Proposed Ninth Edition TNM Classification of Lung Cancer

A universal nomenclature of the anatomic extent of lung cancer has been critical for individual patient care as well as research advances. As progress occurs, new details emerge that need to be included in a refined system that aligns with contemporary clinical management issues. The ninth edition TNM classification of lung cancer, which is scheduled to take effect in January 2025, addresses this need. It is based on a large international database, multidisciplinary input, and extensive statistical analyses. Key features of the ninth edition include validation of the significant changes in the T component introduced in the eighth edition, subdivision of N2 after exploration of fundamentally different ways of categorizing the N component, and further subdivision of the M component. This has led to reordering of the TNM combinations included in stage groups, primarily involving stage groups IIA, IIB, IIIA, and IIIB. This article summarizes the analyses and revisions for the TNM classification of lung cancer to familiarize the broader medical community and facilitate implementation of the ninth edition system.

Metastatic sites as predictors in advanced NSCLC treated with PD-1 inhibitors: a systematic review and meta-analysis

BACKGROUND

Programmed cell death protein 1 (PD-1) inhibitors are the first-line treatment for advanced non-small-cell lung cancer (NSCLC) patients. However, their efficacy in metastatic NSCLC patients remains controversial.

AIM OF THE STUDY

The aim of our study was to evaluate the prognosis of advanced metastatic NSCLC patients treated with PD-1 inhibitors, and discuss the predictive effect of metastatic site on the long-term outcome.

METHODS

The Embase, Ovid Medline, Cochrane Central Register of Controlled Trials, and PubMed databases were systematically screened up to February 10, 2020. Twenty-five eligible studies, involving 8,067 patients that assessed the impact of metastatic sites on survival outcome were incorporated in our study. Overall survival (OS) and progression-free survival (PFS) were described as hazard ratio (HR) with 95% confidence interval (CI).

RESULTS

Among the advanced NSCLC patients, the median proportion of brain, liver, bone, and adrenal gland metastases were 21%, 17%, 35%, and 21%, respectively. Patients with metastases to the brain, liver, and bone had worse OS compared to patients without these metastases when treated with PD-1 inhibitors. Similarly, patients with metastasis to the brain and liver were more likely to progress when treated with PD-1 inhibitors. Besides, patients with multiple metastatic sites had worse PFS compared to patients with one metastatic site, while no significant difference was found in terms of OS.

CONCLUSIONS

Based on the findings of our systematic review and meta-analysis, metastatic sites were independent predictors of the survival outcome for advanced NSCLC patients treated with PD-1 inhibitors.

Computational delineation and quantitative heterogeneity analysis of lung tumor on 18F-FDG PET for radiation dose-escalation

Quantitative measurement and analysis of tumor metabolic activities could provide a more optimal solution to personalized accurate dose painting. We collected PET images of 58 lung cancer patients, in which the tumor exhibits heterogeneous FDG uptake. We design an automated delineation and quantitative heterogeneity measurement of the lung tumor for dose-escalation. For tumor delineation, our algorithm firstly separates the tumor from its adjacent high-uptake tissues using 3D projection masks; then the tumor boundary is delineated with our stopping criterion of joint gradient and intensity affinities. For dose-escalation, tumor sub-volumes with low, moderate and high metabolic activities are extracted and measured. Based on our quantitative heterogeneity measurement, a sub-volume oriented dose-escalation plan is implemented in intensity modulated radiation therapy (IMRT) planning system. With respect to manual tumor delineations by two radiation oncologists, the paired t-test demonstrated our model outperformed the other computational methods in comparison (p < 0.05) and reduced the variability between inter-observers. Compared to standard uniform dose prescription, the dosimetry results demonstrated that the dose-escalation plan statistically boosted the dose delivered to high metabolic tumor sub-volumes (p < 0.05). Meanwhile, the doses received by organs-at-risk (OAR) including the heart, ipsilateral lung and contralateral lung were not statistically different (p > 0.05).

Predicting the prognosis of lung cancer: the evolution of tumor, node and metastasis in the molecular age-challenges and opportunities

The tumor, node and metastasis (TNM) classification of malignant tumors was proposed by Pierre Denoit in the mid-20(th) century to code the anatomic extent of tumors. Soon after, it was accepted by the Union for International Cancer Control and by the American Joint Committee on Cancer, and published in their respective staging manuals. Till 2002, the revisions of the TNM classification were based on the analyses of a database that included over 5,000 patients, and that was managed by Clifton Mountain. These patients originated from North America and almost all of them had undergone surgical treatment. To overcome these limitations, the International Association for the Study of Lung Cancer proposed the creation of an international database of lung cancer patients treated with a wider range of therapeutic modalities. The changes introduced in the 7(th) edition of the TNM classification of lung cancer, published in 2009, derived from the analysis of an international retrospective database of 81,495 patients. The revisions for the 8(th) edition, to be published in 2016, will be based on a new retrospective and prospective international database of 77,156 patients, and will mainly concern tumor size, extrathoracic metastatic disease, and stage grouping. These revisions will improve our capacity to indicate prognosis and will make the TNM classification more robust. In the future the TNM classification will be combined with non-anatomic parameters to define prognostic groups to further refine personalized prognosis.

Diagnosis of lung cancer: a bronchoscopist's perspective

BACKGROUND

Guidelines recommend multiple types of cytologic and tissue samplings in the diagnosis of lung cancer by bronchoscopy, but differences of opinion exist as to the relative value of bronchial brushings and endobronchial or transbronchial biopsies. Our objective was to determine concordance of these procedures by a test of symmetry in a historical cohort referred to the pulmonary diagnostic laboratory.

METHODS

From 1988 to 2001, patients with pathologic confirmation of primary lung cancer were examined by standard bronchoscopic techniques of that period. An electronic medical record system was used, with statistical analysis of symmetry between brushings and biopsies establishing the diagnosis.

RESULTS

Of 968 patients, 98% had bronchoscopy for 624 central and 322 peripheral suspect lesions. Bronchial brushings from 915 patients confirmed pulmonary malignancy in 811 (89%) patients. Endobronchial or transbronchial biopsies from 739 patients showed lung cancer in 603 (82%) cases. Bronchial washings in 16 patients and transthoracic needle biopsies in 30 patients established diagnosis. Transbronchial needle aspiration of mediastinal nodes identified metastases in 94 patients. Only 14 patients required a surgical procedure for diagnosis, but 188 received surgical excision as primary treatment. Statistical evaluation used only patients with both bronchial brushings and endobronchial or transbronchial biopsies. Analysis by a test of symmetry showed a significant difference (P<0.0001).

CONCLUSIONS

Positive, suspicious, and negative specimens were consistent, with bronchial brushings being more sensitive with a lower false-negative rate than endobronchial or transbronchial biopsies. Multiple techniques are recommended for bronchoscopic confirmation of lung cancer, but bronchial brushings should be collected initially, as technical or patient limitations might preclude diagnostic tissue biopsies.

[Correlation between regional node metastasis and imageological characteristics in non-small cell lung cancer]

非小细胞肺癌（non-small cell lung cancer, NSCLC）局部淋巴结（N）分期是影响患者治疗方案选择的关键因素之一。目前临床所使用的无创和有创性N分期方法均有其局限性。研究发现NSCLC的某些影像学特点可预测淋巴结转移的危险性，包括大小、CT密度和氟代脱氧葡萄糖（fluorodeoxyglucose, FDG）标准化摄取值（standardized uptake value, SUV）等。期待系统性多因素分析，以发现影响肺癌淋巴结转移的关键因素。

[Aberrant expression of HDGF and its prognostic values in surgically resected non-small cell lung cancer]

BACKGROUND AND OBJECTIVE

Our previous studies revealed that hepatoma-derived growth factor (HDGF) is highly expressed in non-small cell lung cancer (NSCLC) cells, playing important roles in promoting NSCLC cells growth and invasion. The aim of this study is to detect the expression of HDGF in 158 cases of surgically resected NSCLC and evaluate its clinical significance.

METHODS

Immunohistochemical SP method was used to detect the expression of HDGF in 158 NSCLC tissues and 12 normal control lung tissues. Survival analysis was further conducted.

RESULTS

HDGF was found significantly highly expressed in 158 NSCLC tissues compared with normal control lung tissues (P < 0.001). The 5-year survival rate was 38.2% in HDGF high expression cases, compared with 63.1% in HDGF low expression cases, the difference was statistically significant (P=0.009). Linear correlation analysis discovered a significantly negative correlation between HDGF expression and the survival time (r=-0.183, P=0.022). COX proportion hazard model analysis revealed that pathological stages and HDGF expression were independent prognostic factors for this group of 158 resected NSCLC cases.

CONCLUSIONS

HDGF is highly expressed in human NSCLC tissues, predicting worse prognosis in resected NSCLCs. It might be useful molecular biomarker for predicting the prognosis of resected NSCLCs.

[Comparative survival study between the old and new bronchogenic carcinoma classification]

INTRODUCTION

A new classification of bronchogenic carcinoma has been made by the International Association for the Study of Lung Cancer (IASLC) and published by Frank C. Detterbeck et al in the journal Chest (2009). The Thoracic Surgery Department of the Gerona (Spain) University Hospital has re-staged a series of patients with bronchogenic carcinoma who had attempted curative surgery, with the aim of comparing the survival (survival for T, survival for M, and survival by disease staging) between the old and new classification, and also to determine whether these changes in survival are statistically significant. Another one of the objectives of the study is to see whether there is agreement between the current survival of our surgical series and that published by the IASLC.

PATIENTS AND METHODS

Data on 855 patients who had attempted bronchogenic carcinoma curative surgery were entered into a data base. They were radiologically, clinically and histologically staged according to the new and old staging. Survival was calculated according to the T, M, N, and histology stages. A statistical analysis was performed using the SPSS program and the changes in survival between both classifications were analysed.

RESULTS

No statistically significant changes were observed in survival (P=.58) with the new classification in stage IIA, but there were statistically significant changes in survival (P=.0001) in stage IIIB.

DISCUSSION

The study confirms that the current TNM classification is useful, since it shows changes in survival in 2 histological stages (one of them statistically significant). The survival data of our series now fits better with those provided by the IASLC.

Cerebrospinal fluid M staging for medulloblastoma: reappraisal of Chang's M staging based on the CSF flow

Tumor seeding is a strong negative prognostic factor for patients with medulloblastoma. Because Chang's M staging is based primarily on CT and myelographic findings and might be contradictory to the direction of normal cerebrospinal fluid (CSF) flow, seeding patterns and appropriate staging of medulloblastoma need to be revisited in patients diagnosed in the MRI era. We retrospectively reviewed the clinical and radiological data of 86 patients with a diagnosis of medulloblastoma who were treated in the MRI era. The presence of seeding in each subarachnoid space compartment and the patterns of seeding were analyzed in correlation with patient survival data. Thirty-four patients had gross seeding on perioperative MRI. Thirty-two patients had seeding in the spinal compartment. Sixteen and 12 patients had seeding in the infratentorial and supratentorial compartments, respectively. There was an apparent hierarchy of seeding (ie, from seeding in the spinal compartment up to the supratentorial compartment). Patients with seeding in the spinal compartment had longer progression-free survival (P = .038) and a tendency toward better overall survival (P = .053) compared with patients with seeding in intracranial compartments. We modified Chang's M staging based on the CSF flow and termed this approach "CSF M staging." CSF M staging for medulloblastoma, in which intracranial seeding occupies a higher rank than spinal seeding, was a better predictor of patient prognosis. This modified staging method may be applied to metastatic staging of brain tumors located in the fourth ventricle.

Twin-twin transfusion syndrome: an ethics-based and evidence-based argument for clinical research

Aspects of twin-twin transfusion syndrome (TTTS) diagnosis, treatment alternatives, and research opportunities were considered during a consensus conference that was held by the North American Fetal Therapy Network in 2009. A 3-member scientific consensus panel gathered data from expert conference presentations, postconference communications, and comprehensive scientific literature database searches to develop recommendations for TTTS diagnosis, therapy, and research. The panel recommends retaining the Quintero staging system until a superior system has been validated appropriately. It concludes that there is normative equipoise to justify the performance of randomized clinical trials to identify the optimal treatment strategy for mild TTTS. Recommendations for the design and conduct of clinical trials and observational studies are also provided.

Coping with the unexpected at surgery

In lung cancer surgery, it is best to avoid surprises; this requires knowledge of the reliability of preoperative assessment and careful planning. If this has been done, most of the more common situations should be manageable. If there is limited chest wall, mediastinal or N2 node involvement, one should proceed with resection. Unanticipated T4 tumors or bulky pN2 disease should not come as a surprise, and such patients should be sent to a more experienced center. One has to be careful to practice within the scope of one's knowledge and abilities as well as the sophistication of the institution. It only makes a mistake worse if an intraoperative surprise prompts one to embark on an operation that is beyond the means at hand. Collaborative organization via multidisciplinary tumor boards or inter-institutional interaction allows collective wisdom to promote better outcomes for all.

The new lung cancer staging system

The International Association for the Study of Lung Cancer (IASLC) has conducted an extensive initiative to inform the revision of the lung cancer staging system. This involved development of an international database along with extensive analysis of a large population of patients and their prognoses. This article reviews the recommendations of the IASLC International Staging Committee for the definitions for the TNM descriptors and the stage grouping in the new non-small cell lung cancer staging system.