Commission on Cancer Standards for Lymph Node Sampling and Oncologic Outcomes after Lung Resection.

BACKGROUND: The newest Commission on Cancer (CoC) standards recommend sampling 3 mediastinal and 1 hilar lymph node station, 3(N2)1(N1), for lung cancer resections. However, the relationship between the CoC standards and outcomes has not been thoroughly investigated. METHODS: A prospective institutional database was queried for clinical stage I-III lung resections prior to the implementation of the new standards. The relationship between the 3(N2)1(N1) standard ("guideline concordant") and outcomes (upstaging, complications, receipt of adjuvant therapy, locoregional/distant recurrence, and survival) were assessed using multivariable models and stratified by stage. RESULTS: Of 9,289 pulmonary resections 3048 (33%) were guideline concordant and 6241 (67%) were not. Compared to non-concordant, those who were guideline-concordant had higher rates of nodal upstaging (21% vs 13%; OR 1.32 [95% CI 1.14-1.51] p<0.001) and in-hospital complications (34% vs 27%), (OR 1.17 [95% CI 1.05-1.30], p=0.004), but similar adjuvant systemic therapy administration (19% vs 13%; OR 1.09 [95% CI 0.95-1.24], p=0.2), (98% chemotherapy). Locoregional and distant recurrence were not significantly improved with guideline concordance across clinical stage I, II and III subsets. Overall survival was similar in clinical stages I and II but improved survival was observed among guideline concordant clinical stage III patients (HR 0.85 [95% CI 0.74-0.97], p=0.02). CONCLUSIONS: Sampling 3(N2)1(N1) was associated with increased upstaging and complications but not with decreased recurrence or mortality in clinical stage I or II patients. Survival was improved among concordant, clinical stage III patients. Further study is indicated to determine the ideal lymph node sampling strategy across heterogeneous lung cancer patients.

Effects of Serratus Anterior Plane Block on Early Recovery from Thoracoscopic Lung Resection: A Randomized, Blinded, Placebo-Controlled Trial.

BACKGROUND: The efficacy of serratus anterior plane block (SAPB) for treatment of pain after minimally invasive thoracic surgery remains unclear. This trial assesses the impact of SAPB on postoperative opioid consumption and on measures of early recovery after thoracoscopic lung resection. METHODS: Patients undergoing minimally invasive anatomic lung resection at a single center were randomized to undergo SAPB with 40 mL of injectate containing bupivacaine 0.25%, clonidine 100 mcg, and dexamethasone 4 mg (SAPB group) or sham block with 40 mL of normal saline (placebo group) at the conclusion of surgery. The primary outcome was cumulative intravenous morphine equivalents during the first 24 h postoperatively. Secondary outcomes were intravenous morphine equivalents, pain scores at rest and with cough, inspiratory volume on incentive spirometry, and incidence of nausea/vomiting during the first 48 h postoperatively; Quality of Recovery-15 score on postoperative day 7; and length of stay. RESULTS: Using the protocol-specified intention-to-treat analysis, the median (interquartile range, IQR) intravenous morphine equivalents was 10.6 (5.0 to 27.1) mg in SAPB patients (n=46) versus 18.8 (9.9 to 29.6) mg in placebo patients (n=46) (32% reduction; ratio=0.68 [95% CI, 0.44 to 1.06]; P=0.085). Of the secondary outcomes, only the composite pain with cough scores differed significantly in the SAPB group by a coefficient of -0.41 (95% CI, -0.81 to -0.01; P=0.044). A sensitivity as-treated analysis reported median (IQR) intravenous morphine equivalents of 10.0 (5.0 to 27.2) mg in SAPB patients (n=44) versus 19.9 (10.4 to 29.0) mg in placebo patients (n=48) (36% reduction; ratio=0.64 [95% CI, 0.41 to 1.00]; P=0.048). CONCLUSIONS: The protocol-specified intention-to-treat analysis demonstrated that SAPB did not result in a significant reduction in opioid consumption when added to a multimodal analgesic regimen after thoracoscopic anatomic lung resection. The sensitivity as-treated analysis showed a significant and modest clinical reduction in the primary outcome that warrants further investigation.

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for the M Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The International Association for the Study of Lung Cancer developed a global multicenter database to propose evidence-based revisions for the ninth edition of the TNM classification of pleural mesothelioma (PM). This study analyzes the M category to validate eighth edition M category recommendations. METHODS: Cases were submitted electronically or by transfer of existing institutional databases for patients with histologically or cytologically confirmed PM. The presence and number of metastases (single versus multiple) in each of eight organ systems were reported for patients with M1 disease at diagnosis. Overall survival (OS) was calculated by the Kaplan-Meier method. Differences in OS were assessed by log-rank test. RESULTS: Of 7338 submitted cases, 3598 were eligible and 3221 had sufficient data for clinical staging; 228 cases (7%) were M1. Median overall estimated survival was inferior for M1 compared with M0 patients: 10.5 months versus 21.5 months, respectively (p < 0.0001); estimated 1-year survival was 46% versus 71%, respectively. OS differences between M categories were preserved within histologic subgroups. Among 158 patients with organ-specific documentation of M1 disease, there was no statistically significant difference in OS between those with intrathoracic versus more distant metastatic disease (14.4 mo versus 10.9 mo, p = 0.64). No significant survival difference was detected between patients with metastatic disease in a single-organ system versus multiple-organ systems (12.6 mo versus 8.8 mo, p = 0.45). CONCLUSIONS: This evidence-based analysis of the M category for PM conforms with the eighth edition M descriptors. No changes are proposed in the ninth edition of the mesothelioma M category.

Robotic Resection of Spinal and Paraspinal Tumors.

BACKGROUND AND OBJECTIVES: Robotic arm surgical systems provide minimally invasive access and are commonly used in multiple surgical fields, with limited application in neurosurgery. Our institutional experience has led us to explore the benefits of a neurosurgeon trained to perform robotic surgery as part of a multidisciplinary team. The objective of this study is to evaluate the feasibility, safety, and outcomes of robotic resection for spinal nerve sheath tumors (NST). METHODS: Retrospective case series of robotic-assisted intracavitary approaches and resection of NSTs including thoracic, retroperitoneal, and transperitoneal. Surgical outcomes are compared to a historical cohort of open surgical resection of NSTs. RESULTS: Nineteen cases presented, of which 2 were combined posterior spinal followed by robotic tumor resection. One of 19 cases was converted to an open surgery. Gross total resection was achieved in all cases. There were 2 cases of postoperative Horner's syndrome, and 1 case with an intraoperative durotomy that was repaired primarily with no postoperative sequelae. Median estimated blood loss was 50 cc (range: 5-650) and median length of stay was 1 day (range: 0-6), with 9 (47.4%) patients discharged on postoperative day 1 and 3 (15.8%) patients discharged on an outpatient basis. Compared with our previously reported institutional outcomes for open resection of 25 tumors, there was a significant increase in rates of gross total resection (100 vs 60%, P = .002) and decrease in length of stay (median 1 vs 5 days, P < .0001). CONCLUSION: Robotic resection of complex paraspinal tumors appears safe and effective including for preservation of neurological function and may reduce surgical morbidity. Integration of robotic surgical platforms holds the potential to significantly affect neurological surgery.

Are there features that can predict the unresectability of pleural mesothelioma?

INTRODUCTION: The current clinical staging of pleural mesothelioma (PM) is often discordant with the pathologic staging. This study aimed to identify clinical and radiological features that could help predict unresectability in PM. METHODS: Twenty-two descriptive radiologic features were retrospectively evaluated on preoperative computed tomography (CT) and/or positron emission tomography/CT (PET/CT) performed in patients with presumably resectable PM who underwent surgery. Measurements of maximum and sum pleural thickness at three levels of the thorax (upper, middle, and lower) were taken and stratified based on the cutpoints provided by the International Association for the Study of Lung Cancer (IASLC). Clinical and radiological features, including clinical-stage, were compared between resectable and unresectable tumors by univariate analysis and logistic regression modeling. RESULTS: Of 133 patients, 69/133 (52%) had resectable and 64/133 (48%) had unresectable PM. Asbestos exposure (p = 0.005), neoadjuvant treatment (p = 0.001), clinical T-stage (p < 0.0001), all pleural thickness measurements (p < 0.05), pleural thickness pattern (p < 0.0001) and degree (p = 0.033), lung invasion (p = 0.004), extrapleural space obliteration (p < 0.0001), extension to subphrenic space (p = 0.0004), and two combination variables representing extensive diaphragmatic contact and/or chest wall involvement (p = 0.002) and mediastinal invasion (p < 0.0001) were significant predictors at univariate analysis. At multivariable analysis, all models achieved a strong diagnostic performance (area under the curve (AUC) > 0.8). The two best-performing models were one that included the upper-level maximum pleural thickness, extrapleural space obliteration, and mediastinal infiltration (AUC = 0.876), and another that integrated clinical variables and radiological assessment through the clinical T-stage (AUC = 0.879). CONCLUSION: Selected clinical and radiologic features, including pleural thickness measurements, appear to be strong predictors of unresectability in PM. CLINICAL RELEVANCE STATEMENT: A more accurate prediction of unresectability in the preoperative assessment of patients with pleural mesothelioma may avoid unnecessary surgery and prompt initiation of nonsurgical treatments. KEY POINTS: About half of pleural mesothelioma patients are reported to receive an incorrect disease stage preoperatively. Eleven features identified as predictors of unresectability were included in strongly performing predictive models. More accurate preoperative staging will help clinicians and patients choose the most appropriate treatments.

Determinants of successful minimally invasive surgery for resectable non-small cell lung cancer after neoadjuvant therapy.

OBJECTIVE: Minimally invasive surgery (MIS) (video-assisted thoracoscopic surgery and robot-assisted thoracoscopic surgery) for pulmonary resection is standard in early-stage non-small cell lung cancer because it is associated with better perioperative outcomes than thoracotomy. MIS for resection of more advanced non-small cell lung cancer (Stages IB-IIIB) treated with neoadjuvant therapy has been utilized. However, the determinants of success are not well defined. METHODS: A single institution retrospective review of a prospectively maintained database was conducted, querying for patients with clinical Stage IB through IIIB non-small cell lung cancer who had resection after neoadjuvant systemic therapy without radiation from 2013 to 2022. Patients were grouped by surgical approach; that is, open versus MIS. Successful MIS was defined by no conversion, R0 resection, and no major (grade 3 or greater) morbidity. Analyses by intent-to-treat assessed outcomes by Wilcoxon rank-sum test and Fisher exact test. (Multivariable regression analysis identified variables that contributed to successful MIS resection.) RESULTS: Of 627 eligible patients, 360 (57%) had open and 267 (43%) had MIS procedures. Most patients (79.1%) received neoadjuvant platinum-based chemotherapy, and 21.9% were treated with immunotherapy or targeted therapy alone or combined with chemotherapy. Among MIS resections, 179 (67%) were performed by video-assisted thoracoscopic surgery and 88 (33%) by robot-assisted thoracoscopic surgery. The conversion rate was 16% (n = 43). Successful MIS resection was achieved in 77% of patients. Multivariable regression analysis showed that pretreatment clinical N stage was a significant determinant of success, but not pretreatment clinical T stage or type of neoadjuvant therapy. CONCLUSIONS: Following neoadjuvant systemic therapy for clinical stage IB or IIIB non-small cell lung cancer, MIS resection can be successfully accomplished and should be considered in appropriate patients. Presence of pretreatment nodal disease is associated with higher odds of conversion, major morbidity, and incomplete resection.

Outcomes of Patients Undergoing Segmentectomy for Occult Node-Positive Clinical Stage IA Lung Cancer.

BACKGROUND: Results of recent clinical trials suggest that segmentectomy may be an acceptable alternative to lobectomy for selected patients with early-stage non-small cell lung cancer (NSCLC). Increased use of segmentectomy may result in a concomitant increase in occult node-positive (N+) disease on surgical pathology examination. The optimal management for such patients remains unknown. METHODS: Clinicopathologic data were abstracted from a prospective institutional database to identify patients with pathologic N+ disease after segmentectomy for cT1 N0 M0 NSCLC. Propensity score matching identified a comparable lobectomy cohort for assessment of cumulative incidence of recurrence and overall survival (OS). RESULTS: Of 759 included patients, 27 (4%) had nodal upstaging on the final pathology report. Of these 27 patients, 4 (15%) had skip metastasis to N2 stations, and 20 (74%) received adjuvant therapy; no completion lobectomies were performed. Ten patients (37%) had disease recurrence: 3 isolated locoregional (11%) and 7 distant (26%). The median time to recurrence among patients with recurrence was 1.8 years; OS after recurrence was 3.4 years. After 5:1 matching with 109 patients who underwent lobectomy, all variables were balanced between the groups, except pathologic N2 stage and open surgical approach. The 5-year cumulative incidence of recurrence was not significantly different between segmentectomy and lobectomy (42% vs 52%, respectively; Gray's P = .1). The 5-year OS (63% and 50%) and rate of locoregional recurrence (12% vs 13%) were not statistically different between the groups. CONCLUSIONS: Patients with occult N+ disease after segmentectomy for cT1 N0 M0 NSCLC had limited isolated locoregional recurrences and outcomes similar to those in patients who underwent lobectomy. Lobectomy may not provide an advantage in these patients.

High-risk features associated with recurrence in stage I lung adenocarcinoma.

OBJECTIVE: There is a lack of knowledge regarding the use of prognostic features in stage I lung adenocarcinoma (LUAD). Thus, we investigated clinicopathologic features associated with recurrence after complete resection for stage I LUAD. METHODS: We performed a retrospective analysis of patients with pathologic stage I LUAD who underwent R0 resection from 2010 to 2020. Exclusion criteria included history of lung cancer, induction or adjuvant therapy, noninvasive or mucinous LUAD, and death within 90 days of surgery. Fine and Gray competing-risk regression assessed associations between clinicopathologic features and disease recurrence. RESULTS: In total, 1912 patients met inclusion criteria. Most patients (1565 [82%]) had stage IA LUAD, and 250 developed recurrence: 141 (56%) distant and 109 (44%) locoregional only. The 5-year cumulative incidence of recurrence was 12% (95% CI, 11%-14%). Higher maximum standardized uptake value of the primary tumor (hazard ratio [HR], 1.04), sublobar resection (HR, 2.04), higher International Association for the Study of Lung Cancer grade (HR, 5.32 [grade 2]; HR, 7.93 [grade 3]), lymphovascular invasion (HR, 1.70), visceral pleural invasion (HR, 1.54), and tumor size (HR, 1.30) were independently associated with a hazard of recurrence. Tumors with 3 to 4 high-risk features had a higher cumulative incidence of recurrence at 5 years than tumors without these features (30% vs 4%; P < .001). CONCLUSIONS: Recurrence after resection for stage I LUAD remains an issue for select patients. Commonly reported clinicopathologic features can be used to define patients at high risk of recurrence and should be considered when assessing the prognosis of patients with stage I disease.

The International Association for the Study of Lung Cancer Pleural Mesothelioma Staging Project: Proposal for Revision of the TNM Stage Groupings in the Forthcoming (Ninth) Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The eighth edition of the TNM classification of pleural mesothelioma (PM) saw substantial changes in T and N components and stage groupings. The International Association for the Study of Lung Cancer collected data into a multinational database to further refine this classification. This ninth edition proposal incorporates changes proposed in the clinical (c)T component but not the pathologic T component, to include size criteria, and further refines TNM stage groupings for PM. METHODS: Data were submitted through electronic data capture or batch transfer from institutional databases. Survival was measured from diagnosis date. Candidate stage groups were developed using a recursive partitioning and amalgamation algorithm applied to all cM0 cases for clinical stage and subsequently for pathologic stage. Cox models were developed to estimate survival for each stage group. RESULTS: Of 3598 submitted cases, 2192 were analyzable for overall clinical stage and 445 for overall pathologic stage. Recursive partitioning and amalgamation generated survival tree on overall survival outcomes restricted to cM0, with newly proposed (ninth edition) cT and cN component-derived optimal stage groupings of stage I (T1N0), II (T1N1; T2N0), IIIA (T1N2; T2N1/2; any T3), IIIB (any T4), and IV (any M1). Although cT and pathologic T descriptors are different in the ninth edition, aligning pathologic stage groupings with clinical stage produced better discrimination than did retaining eighth edition pathologic stage groupings. CONCLUSIONS: To our knowledge, this revision of the clinical TNM classification for PM is the first to incorporate the measurement-based proposed changes in cT category. The pathologic TNM aligns with clinical TNM.

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for the "N" Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The International Association for the Study of Lung Cancer developed an international database to inform potential revisions in the ninth edition of the TNM classification of diffuse pleural mesothelioma (PM). This study analyzed the clinical and pathologic N categories to determine whether revisions were indicated relative to the eighth edition staging system. METHODS: Of 7338 PM cases diagnosed from 2013 to 2022 and 3598 met all inclusion criteria for planned analyses. Data on 2836 patients without metastases were included in this study. Overall survival (OS) was measured from date of diagnosis. Patients were included regardless of whether they received neoadjuvant treatment. For the pathologic N analysis, patients who underwent resection (extrapleural pneumonectomy or pleurectomy/decortication) were included. N subgroups were analyzed and OS assessed by the Kaplan-Meier method. RESULTS: The existing eighth edition N categories were performed adequately in the ninth edition data set. A median OS advantage was noted for clinical and pathologic N0 versus N1 patients: 23.2 versus 18.5 and 33.8 versus 25.0 months, respectively. Patients with resected pN0 had a 3-year OS of 48%. No difference in OS was noted for single- versus multiple-station nodal metastases. The number of nodal stations sampled at the time of resection was not associated with a difference in OS. CONCLUSIONS: Data regarding clinical and pathologic N categories corroborate those used in the eighth edition. No changes in the N categories are recommended in the ninth edition of PM staging system.

A Real-World Assessment of Stage I Lung Cancer Through Electronic Nose Technology.

INTRODUCTION: Electronic nose (E-nose) technology has reported excellent sensitivity and specificity in the setting of lung cancer screening. However, the performance of E-nose specifically for early-stage tumors remains unclear. Therefore, the aim of our study was to assess the diagnostic performance of E-nose technology in clinical stage I lung cancer. METHODS: This phase IIc trial (NCT04734145) included patients diagnosed with a single greater than or equal to 50% solid stage I nodule. Exhalates were prospectively collected from January 2020 to August 2023. Blinded bioengineers analyzed the exhalates, using E-nose technology to determine the probability of malignancy. Patients were stratified into three risk groups (low-risk, [<0.2]; moderate-risk, [≥0.2-0.7]; high-risk, [≥0.7]). The primary outcome was the diagnostic performance of E-nose versus histopathology (accuracy and F1 score). The secondary outcome was the clinical performance of the E-nose versus clinicoradiological prediction models. RESULTS: Based on the predefined cutoff (<0.20), E-nose agreed with histopathologic results in 86% of cases, achieving an F1 score of 92.5%, based on 86 true positives, two false negatives, and 12 false positives (n = 100). E-nose would refer fewer patients with malignant nodules to observation (low-risk: 2 versus 9 and 11, respectively; p = 0.028 and p = 0.011) than would the Swensen and Brock models and more patients with malignant nodules to treatment without biopsy (high-risk: 27 versus 19 and 6, respectively; p = 0.057 and p < 0.001). CONCLUSIONS: In the setting of clinical stage I lung cancer, E-nose agrees well with histopathology. Accordingly, E-nose technology can be used in addition to imaging or as part of a "multiomics" platform.

A New Functional Threshold for Minimally Invasive Lobectomy.

OBJECTIVE: To assess the performance of a lower predicted postoperative (ppo) forced expiratory volume in 1 second (FEV1) or diffusion capacity of the lung for carbon monoxide (DLCO) (ppoFEV1/ppoDLCO) threshold to predict cardiopulmonary complications after minimally invasive surgery (MIS) lobectomy. SUMMARY BACKGROUND DATA: Although MIS is associated with better postoperative outcomes than open surgery, MIS uses risk-assessment algorithms developed for open surgery. Moreover, several different definitions of cardiopulmonary complications are used for assessment. METHODS: All patients who underwent MIS lobectomy for clinical stage I-II lung cancer from 2018 to 2022 at our institution were considered. The performance of a ppoFEV1/ppoDLCO threshold of <45% was compared against that of the current guideline threshold of <60%. Three different definitions of cardiopulmonary complications were compared: Society of Thoracic Surgeons (STS), European Society of Thoracic Surgeons (ESTS), and Berry et al. RESULTS: In 946 patients, the ppoFEV1/ppoDLCO threshold of <45% was associated with a higher proportion correctly classified (79% [95% CI, 76%-81%] vs. 65% [95% CI, 62%-68%]; P<0.001). The complication with the biggest difference in incidence between ppoFEV1/ppoDLCO of 45%-60% and >60% was prolonged air leak (33 [13%] vs. 34 [6%]; P<0.001). The predicted probability curves for cardiopulmonary complications were higher for the STS definition than for the ESTS or Berry definitions across ppoFEV1 and ppoDLCO values. CONCLUSIONS: The ppoFEV1/ppoDLCO threshold of <45% more accurately classified patients for cardiopulmonary complications after MIS lobectomy, emphasizing the need for updated risk-assessment guidelines for MIS lobectomy to optimize additional cardiopulmonary function evaluation.

Perioperative Immunotherapy for Node-Negative Non-Small Cell Lung Cancer-Current Evidence and Future Directions.

Neoadjuvant immunotherapy has gone from an idea to an indication in locally advanced lung cancer. Several phase III trials have demonstrated the superiority of neoadjuvant chemoimmunotherapy compared with chemotherapy in this setting. Although such progress has revolutionized the treatment of locally advanced disease, the unmet needs of stage I and stage II patients without lymph node disease have largely been underrepresented in existing trials. Up-front resection with few patients going on to complete adjuvant therapy remains the norm for most stage I and II patients. Emerging evidence now supports the exploration of supplemental checkpoint blockade in well-selected early-stage, node-negative patients with large tumors and no actionable driver mutations. Although concerns surrounding safety and risk exist, patient selection could be substantially improved using novel biomarker approaches that leverage our understanding of the tumor immune microenvironment of lung cancer. This review provides a comprehensive overview of the opportunities and controversies of perioperative immunotherapy in node-negative lung cancer.

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for Revision of the TNM Stage Groups in the Forthcoming (Ninth) Edition of the TNM Classification for Lung Cancer.

INTRODUCTION: The TNM classification of lung cancer is periodically revised. The International Association for the Study of Lung Cancer collected and analyzed a new database to inform the forthcoming ninth edition of the TNM classification. The results are herewith presented. METHODS: After exclusions, 76,518 patients from a total of 124,581 registered patients were available for analyses: 58,193 with clinical stage, 39,192 with pathologic stage, and 62,611 with best stage NSCLC. The proposed new N2 subcategories (N2a, involvement of single ipsilateral mediastinal or subcarinal nodal station, and N2b, involvement of multiple ipsilateral mediastinal nodal stations with or without involvement of the subcarinal nodal station) and the new M1c subcategories (M1c1, multiple extrathoracic metastases in one organ system, and M1c2, multiple extrathoracic metastases in multiple organ systems) were considered in the survival analyses. Several potential stage groupings were evaluated, using multiple analyses, including recursive partitioning, assessment of homogeneity within and discrimination between potential groups, clinical and statistical significance of survival differences, multivariable regression, and broad assessment of generalizability. RESULTS: T1N1, T1N2a, and T3N2a subgroups are assigned to IIA, IIB, and IIIA stage groups, respectively. T2aN2b and T2bN2b subgroups are assigned to IIIB. M1c1 and M1c2 remain in stage group IVB. Analyses reveal consistent ordering, discrimination of prognosis, and broad generalizability of the proposed ninth edition stage classification of lung cancer. CONCLUSIONS: The proposed stages for the ninth edition TNM improve the granularity of nomenclature about anatomic extent that has benefits as treatment approaches become increasingly differentiated and complex.

The International Association for the Study of Lung Cancer (IASLC) Staging Project for Lung Cancer: Recommendation to Introduce Spread Through Air Spaces as a Histologic Descriptor in the Ninth Edition of the TNM Classification of Lung Cancer. Analysis of 4061 Pathologic Stage I NSCLC.

INTRODUCTION: Spread through air spaces (STAS) consists of lung cancer tumor cells that are identified beyond the edge of the main tumor in the surrounding alveolar parenchyma. It has been reported by meta-analyses to be an independent prognostic factor in the major histologic types of lung cancer, but its role in lung cancer staging is not established. METHODS: To assess the clinical importance of STAS in lung cancer staging, we evaluated 4061 surgically resected pathologic stage I R0 NSCLC collected from around the world in the International Association for the Study of Lung Cancer database. We focused on whether STAS could be a useful additional histologic descriptor to supplement the existing ones of visceral pleural invasion (VPI) and lymphovascular invasion (LVI). RESULTS: STAS was found in 930 of 4061 of the pathologic stage I NSCLC (22.9%). Patients with tumors exhibiting STAS had a significantly worse recurrence-free and overall survival in both univariate and multivariable analyses involving cohorts consisting of all NSCLC, specific histologic types (adenocarcinoma and other NSCLC), and extent of resection (lobar and sublobar). Interestingly, STAS was independent of VPI in all of these analyses. CONCLUSIONS: These data support our recommendation to include STAS as a histologic descriptor for the Ninth Edition of the TNM Classification of Lung Cancer. Hopefully, gathering these data in the coming years will facilitate a thorough analysis to better understand the relative impact of STAS, LVI, and VPI on lung cancer staging for the Tenth Edition TNM Stage Classification.

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for Revisions of the "T" Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The primary tumor (T) component in the eighth edition of pleural mesothelioma (PM) staging system is based on pleural involvement and extent of invasion. Quantitative assessment of pleural tumor has been found to be prognostic. We explored quantitative and qualitative metrics to develop recommendations for T descriptors in the upcoming ninth edition of the PM staging system. METHODS: The International Association for the Study of Lung Cancer prospectively collected data on patients with PM. Sum of maximum pleural thickness (Psum) was recorded. Optimal combinations of Psum and eighth edition cT descriptors were assessed using recursive binary splitting algorithm, with bootstrap resampling to correct for the adaptive nature of the splitting algorithm, and validated in the eighth edition data. Overall survival (OS) was calculated by the Kaplan-Meier method and differences in OS assessed by the log-rank test. RESULTS: Of 7338 patients submitted, 3598 were eligible for cT analysis and 1790 had Psum measurements. Recursive partitioning identified optimal cutpoints of Psum at 12 and 30 mm, which, in combination with extent of invasion, yielded four prognostic groups for OS. Fmax greater than 5 mm indicated poor prognosis. cT4 category (based on invasion) revealed similar performance to eighth edition. Three eighth edition descriptors were eliminated based on low predictive accuracy. Eighth edition pT descriptors remained valid in ninth edition analyses. CONCLUSION: Given reproducible prognostication by Psum, size criteria will be incorporated into cT1 to T3 categories in the ninth edition. Current cT4 category and all pT descriptors will be maintained, with reclassification of fissural invasion as pT2.