Prognostic value of the international association for the study of lung cancer grading system and its association with the tumor microenvironment in stage I EGFR-muted lung adenocarcinoma.

INTRODUCTION: The International Association for the Study of Lung Cancer (IASLC) grading system predicts early lung adenocarcinoma outcomes. METHODS: The purpose of this study is to examine prognostic value of the IASLC grading system and its association with the tumor microenvironment (TME) in Stage I EGFR-muted lung adenocarcinoma. Based on the IASLC grading system, we compared the clinicopathological characteristics of EGFR-mutated lung adenocarcinoma (n = 296). In addition, we examined the expression level of E-cadherin in tumor cells and counted the number of tumor-infiltrating lymphocytes (TILs; CD8, CD20, CD138, and Foxp3), tumor-associated macrophages (TAMs; CD204), and cancer-associated fibroblasts (CAFs; podoplanin) using semi-automatic digital pathology image analysis. RESULTS: Recurrence-free survival (RFS) curve showed that survival of grade 3 was significantly shorter than that of grade 1 (P < 0.01) and grade 2 (P = 0.03). Multivariate analysis of RFS revealed the invasive size, lymphatic permeation, and grade 3 (P < 0.01) as independent poor prognostic factors. The number of CD204 +TAMs and PDPN+CAFs was significantly higher in grade 3 than in grade 1 or 2 (all P < 0.01). Among the intermediate grade by the predominant subtype based classification, cases classified as grade 3 by the new classification had higher number of CD204 +TAMs (P < 0.01) and PDPN+CAFs (P = 0.02) than those classified as grade 2. CONCLUSION: The IASLC grading system correlated with the outcomes of EGFR-mutated lung adenocarcinoma. Grade 3 was found to have the TME that most contributes to tumor progression, which probably explained their poor prognosis.

Prognostic significance of micronest in cancer stroma in resected lung squamous cell carcinoma.

Tumor budding in the cancer stroma has been reported to be a prognostic factor in non-small cell lung cancer. Micronest in cancer stroma (MICS) is often observed as a formation that is larger and more conspicuous than budding, but its clinicopathologic significance is unclear. In this study, we aimed to examine the clinicopathological significance of MICS in lung squamous cell carcinoma (LSqCC). A total of 198 consecutive patients with pathologically diagnosed LSqCC (anyT N0-1M0) were enrolled in this study. MICS were defined as those that met the following criteria: (1) consisting of 5-200 tumor cells or less than 200 µm in diameter and (2) more than 200 µm away from the adjacent main lesion. The prognostic impact of the presence or absence of MICS and the characteristics of MICS-forming cancer cells were evaluated by immunohistochemistry (IHC). MICS was observed in 57 patients (28.8%), and overall survival (OS) and recurrence-free survival (RFS) were significantly shorter in the MICS-positive group (OS: 44.4% vs. 84.4%, p < 0.001; RFS: 30.0% vs. 82.6%, p < 0.001). Univariate and multivariate analyses revealed that the presence of MICS was an independent poor prognostic factor for OS (hazard ratio [HR] 3.54, p < 0.001) and RFS (HR 4.99, p < 0.001). Immunohistochemistry showed that the expression levels of the cell-cell adhesion molecule E-cadherin and hypoxia-induced protein GLUT-1 were significantly decreased in cancer cells forming MICS lesions compared to the tumor component excluding MICS within the same tumor (non-MICS lesions). Our data show that MICS is a distinct morphological feature with important biological and prognostic significance.

A case of lung metastasis from gastric cancer presenting as ground-glass opacity dominant nodules.

BACKGROUND: Most metastatic lung tumors present as solid nodules on chest computed tomography (CT). In contrast, ground-glass opacity on chest computed tomography usually suggests low-grade malignant lesions such as adenocarcinoma in situ or atypical adenomatous hyperplasia of the lung. CASE PRESENTATION: A 75-year-old woman with a history of gastric cancer surgery approximately 5 years prior was referred to the Department of Thoracic Surgery at our hospital because of two newly appearing pulmonary ground-glass opacity-dominant nodules on chest computed tomography. She had two ground-glass opacities in the right lower lobe, one in the S6 segment was 12 mm and the other in the S10 segment was 8 mm. On chest computed tomography 15 months prior to referral, the lesion in the S6 segment was 8 mm, and the lesion in the S10 segment was 2 mm. She was suspected to have primary lung cancer and underwent wide-wedge resection of the nodule in the S6 segment. In the resected specimen, polygonal tumor cells infiltrated the alveolar septa, with some tumor cells exhibiting signet ring cell morphology. Based on morphological similarities to the tumor cells of previous gastric cancers and the results of immunostaining, the patient was diagnosed with lung metastases of gastric cancer. CONCLUSIONS: Pulmonary nodules in patients with a history of cancer in other organs, even if ground-glass opacity is predominant, should also be considered for the possibility of metastatic pulmonary tumors if they are growing rapidly.

Effect of Resected Lung Volume on Pulmonary Function and Residual Lung Volume in Patients Undergoing Segmentectomy: A Retrospective Study.

PURPOSE: We elucidated the effects of planned resection volume on postoperative pulmonary function and changes in residual lung volume during segmentectomy. METHODS: This study included patients who underwent thoracoscopic segmentectomy between January 2017 and December 2022 and met eligibility criteria. Pre- and post-resection spirometry and computed tomography were performed. Three-dimensional reconstructions were performed by using computed tomography images to calculate the volumes of the resected, remaining, and nonoperative side regions. Based on the resected region volume, patients were divided into the higher and lower volume segmentectomy groups. Changes in lung volume and pulmonary function before and after the surgery were comparatively analyzed. RESULTS: The median percentage of resected lung volume was 10.9%, forming the basis for categorizing patients into the two groups. Postoperative forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) ratios to preoperative measurements in both groups did not differ significantly (FEV1, p = 0.254; FVC, p = 0.777). Postoperative FEV1 and FVC ratios to their predicted postoperative values were significantly higher in the higher volume segmentectomy group than in the lower volume segmentectomy group (FEV1, p = 0003; FVC, p < 0.001). The higher volume segmentectomy group showed significantly greater post-to-preoperative lung volume ratio in overall, contralateral, ipsilateral, residual lobe and residual segment than the lower volume segmentectomy group. CONCLUSIONS: Postoperative respiratory function did not differ significantly between the higher- and lower-volume segmentectomy groups, indicating improved respiratory function because of substantial postoperative residual lung expansion. Our findings would aid in determining the extent of resection during segmentectomy.

Clinicopathological differences between EGFR mutated and EGFR wild-type lung adenocarcinoma with papillary predominant pattern.

OBJECTIVES: We aimed to reveal the clinicopathological differences between epidermal growth factor receptor (EGFR)-mutated and wild-type (WT) lung adenocarcinoma (LUAD) focusing on the predominant subtype. METHODS: This study included 352 with EGFR mutation and 370 with WT patients in consecutive stage I LUAD classified by the predominant subtype, and their clinicopathological characteristics and prognosis were analyzed. Using the Cancer Genome Atlas Program (TCGA) cohort, we analyzed differences in gene expression between EGFR mutation and WT groups. Furthermore, we performed immunohistochemical evaluations for 46 with EGFR mutation and 47 with WT patients in consecutive stage I papillary predominant adenocarcinoma (PPA). RESULTS: Compared to the PPA with WT [n = 115], those with EGFR mutation [n = 99] exhibited smaller invasive size (p = 0.03) and less frequent vessel invasion (p < 0.01). However, PPA with EGFR mutation showed significantly worse 5-ys recurrence-free survival (RFS) rates compared to those with WT (70.6 % versus 83.3 %, p = 0.03). Contrarily, no significant differences were observed in other predominant subtypes. In the TCGA cohort, PPA with EGFR mutation tended to show higher expression of galectin-3, which is associated with tumor metastasis and resistance to anoikis, compared to those with WT (p = 0.06). Immunohistochemical evaluation revealed that galectin-3 expression was significantly higher in PPA with EGFR mutation than in those with WT (p < 0.01). CONCLUSIONS: The prognosis of PPA with EGFR mutation proved to be less favorable compared to that with WT, and galectin-3 is highly expressed in EGFR-mutated PPA.

A randomized phase III trial of postoperative surveillance for pathological stage II and IIIA non-small cell lung cancer (JCOG2012, PHOENIX).

The goal of postoperative surveillance following non-small cell lung cancer surgery is to detect recurrence and second primary malignancies while curative treatment is still possible. Although several guidelines recommend that patients have computed tomography (CT) scans every 6 months for the first 2 years after resection, then once a year, there is no evidence that it is effective for survival, especially in locally advanced non-small cell lung cancer. In October 2022, we launched a multi-institutional, randomized controlled phase III trial for pathological stage II and IIIA non-small cell lung cancer patients to confirm the non-inferiority of less intensive surveillance with less frequent CT scans versus standard surveillance in terms of overall survival. The primary endpoint is overall survival. We intend to enroll 1100 patients from 45 institutions over 4 years. The trial has been registered in the Japan Registry of Clinical Trials under the code jRCT1030220361 (https://jrct.niph.go.jp/latest-detail/jRCT1030220361).

Spatial intratumor heterogeneity of programmed death-ligand 1 expression predicts poor prognosis in resected non-small cell lung cancer.

BACKGROUND: We quantified the pathological spatial intratumor heterogeneity of programmed death-ligand 1 (PD-L1) expression and investigated its relevance to patient outcomes in surgically resected non-small cell lung carcinoma (NSCLC). METHODS: This study enrolled 239 consecutive surgically resected NSCLC specimens of pathological stage IIA-IIIB. To characterize the spatial intratumor heterogeneity of PD-L1 expression in NSCLC tissues, we developed a mathematical model based on texture image analysis and determined the spatial heterogeneity index of PD-L1 for each tumor. The correlation between the spatial heterogeneity index of PD-L1 values and clinicopathological characteristics, including prognosis, was analyzed. Furthermore, an independent cohort of 70 cases was analyzed for model validation. RESULTS: Clinicopathological analysis showed correlations between high spatial heterogeneity index of PD-L1 values and histological subtype (squamous cell carcinoma; P < .001) and vascular invasion (P = .004). Survival analysis revealed that patients with high spatial heterogeneity index of PD-L1 values presented a significantly worse recurrence-free rate than those with low spatial heterogeneity index of PD-L1 values (5-year recurrence-free survival [RFS] = 26.3% vs 47.1%, P < .005). The impact of spatial heterogeneity index of PD-L1 on cancer survival rates was verified through validation in an independent cohort. Additionally, high spatial heterogeneity index of PD-L1 values were associated with tumor recurrence in squamous cell carcinoma (5-year RFS = 29.2% vs 52.8%, P < .05) and adenocarcinoma (5-year RFS = 19.6% vs 43.0%, P < .01). Moreover, we demonstrated that a high spatial heterogeneity index of PD-L1 value was an independent risk factor for tumor recurrence. CONCLUSIONS: We presented an image analysis model to quantify the spatial intratumor heterogeneity of protein expression in tumor tissues. This model demonstrated that the spatial intratumor heterogeneity of PD-L1 expression in surgically resected NSCLC predicts poor patient outcomes.

Long-term outcomes of 5-year survivors without recurrence after the complete resection of non-small cell lung cancer after lobectomy: a landmark analysis in consideration of competing risks.

PURPOSE: Among non-small cell lung cancers (NSCLC), 5 years is a benchmark in cancer control and treatment, but a certain percentage of cases recur after 5 years. The long-term post-recurrence outcomes remain controversial. To examine the accurate prognostic factors associated with survival and cancer recurrence among 5-year survivors, a landmark analysis that considered competing risks was performed. METHODS: Complete resection of NSCLC was performed in 2482 patients between January 2003 and December 2015. A total of 1431 patients were 5-year survivors without recurrence. A landmark time analysis was applied to the overall survival (OS) and recurrence-free survival (RFS) from 5 years after surgery, and the findings were calculated using the Kaplan-Meier method. The cumulative incidence of cause-specific death and recurrence was estimated using the cumulative incidence function, while carefully considering the competing risks. RESULTS: Postoperative recurrence was detected in 732 patients, of whom 68 (9.3%) had recurrence after 5 years. The median follow-up period was 8.2 years. In the competing risk analysis, the independent poor prognostic factors associated with cause-specific death were age ≥ 75 years, lymph node metastasis and pleural invasion. CONCLUSIONS: Patients requiring a follow-up for > 5 years were aged ≥ 75 years and had either lymph node metastasis or pleural invasion.

EGFR mutation impacts recurrence in high-risk early-stage lung adenocarcinoma in the IASLC grading system.

INTRODUCTION: The developments of perioperative treatments for patients with high-risk early-stage lung cancer are ongoing, however, real-world data and evidence of clinical significance of genetic aberration are lacking in this population. This study aimed to identify patients with early-stage lung adenocarcinoma at high risk for recurrence based on pathological indicators of poor prognosis, including the International Association for the Study of Lung Cancer (IASLC) grade, and elucidate the prognostic impact of epidermal growth factor receptor mutation (EGFRm) status. METHODS: This retrospective study included 494 consecutive patients who underwent complete resection for pathological stage I lung adenocarcinoma between 2011 and 2016. The patients were evaluated for EGFRm and IASLC grade. Multivariable analysis was used to identify pathological factors for poor prognosis associated with recurrence-free survival (RFS) and overall survival (OS). Patients with any one of these factors were classified into the high-risk group. The prognostic impact of EGFRm was evaluated using RFS, OS, and cumulative recurrence proportion. RESULTS: Multivariable analysis for RFS and OS revealed that IASLC grade 3, pathological invasion size>2 cm, and presence of lymphovascular invasion were indicators of poor prognosis. EGFRm-positive patients had a higher incidence of all types of recurrence, including central nervous system (CNS) metastasis and distant metastasis in high-risk group, but not in low-risk group. CONCLUSIONS: This study provides evidence that patients with EGFRm-positive stage I lung adenocarcinoma in the high-risk group have an increased risk of recurrence, including CNS metastasis. These findings highlight the need for development of adjuvant treatment in this population.

Ten-year follow-up outcomes of limited resection trial for radiologically less-invasive lung cancer.

BACKGROUND: The JCOG0804/WJOG4507L single-arm confirmatory trial indicated a satisfactory 10-year prognosis for patients who underwent limited resection for radiologically less-invasive lung cancer. However, only one prospective trial has reported a 10-year prognosis. METHODS: We conducted a multicenter prospective study coordinated by the National Cancer Center Hospital East and Kanagawa Cancer Center. We analyzed the long-term prognosis of 100 patients who underwent limited resection of a radiologically less-invasive lung cancer in the peripheral lung field. We defined radiologically less-invasive lung cancer as lung adenocarcinoma with a maximum tumor diameter of ≤2 cm, tumor disappearance ratio of ≥0.5 and cN0. The primary endpoint was the 10-year local recurrence-free survival. RESULTS: Our patients, with a median age of 62 years, included 39 males. A total of 58 patients were non-smokers; 87 had undergone wide wedge resection and 9 underwent segmentectomy. A total of four cases were converted to lobectomy because of the presence of poorly differentiated components in the frozen specimen or insufficient margin with segmentectomy. The median follow-up duration was 120.9 months. The 10-year recurrence-free survival and overall survival rates of patients with lung cancer were both 96.0%. Following the 10-year long-term follow-up, two patients experienced recurrences at resection ends after wedge resection. CONCLUSIONS: Limited resection imparted a satisfactory prognosis for patients with radiologically less-invasive lung cancer, except two cases of local recurrence >5 years after surgery. These findings suggest that patients with this condition who underwent limited resection may require continued follow-up >5 years after surgery.

Predictors of residual simultaneous multiple ground-glass nodule progression after dominant lesion resection.

OBJECTIVE: This study aimed to identify the predictive factors for the progression of residual simultaneous multifocal ground-glass nodules (SMGGNs) after resection of the dominant lesion. METHODS: Patients (n = 3420) with primary lung cancer who underwent lung resections at our hospital between 2006 and 2016 were screened, and the data from 82 patients who had residual SMGGNs after undergoing surgery for the dominant lesion (pathologically stage 0-IIA) were retrospectively analyzed. Clinicopathological factors that predicted the growth of residual second dominant GGNs were identified. RESULTS: Median total tumor and solid component sizes of the residual second dominant GGNs were 1.3 cm (interquartile range [IQR]: 0.6-2.0) and 0 cm (IQR: 0-0.7), respectively. During a median follow-up period of 54 months (IQR: 37-78 months), 35 (43%) lesions progressed. Logistic regression analysis revealed that age younger than 70 (OR: 10.54, 95% CI: 1.71-65.11), a dominant lesion with pure solid appearance (reference: GGN, OR: 18.16, 95% CI: 1.66-198.60), a second dominant GGN total size larger than 1.0 cm (OR: 12.27, 95% CI: 1.85-81.17), and a second dominant GGN solid component size larger than 0.5 cm (OR: 17.59, 95% CI: 3.58-86.47) were significant predictive factors for the progression of residual GGNs (all p values < 0.03). Based on an analysis of growth patterns, rapid growth was higher in second dominant GGNs with a part-solid appearance. CONCLUSIONS: If the resected dominant lesion or the residual second dominant GGN exhibits high-risk factors, the second dominant GGN should be meticulously observed.

An accurate prediction of negative lymph node metastasis with consideration of glucose metabolism in early-stage non-small cell lung cancer.

OBJECTIVE: We aimed to identify risk factors in lymph node metastasis in early-stage non-small cell lung cancer (NSCLC) and predict lymph node metastasis. METHODS: A total of 416 patients with clinical stage IA2-3 NSCLC who underwent lobectomy and lymph node dissection between July 2016 and December 2020 at National Cancer Center Hospital East were included. Multivariable logistic regression was performed to develop a model for predicting lymph node metastasis. Leave-one-out cross-validation was performed to evaluate the developing prediction model, and sensitivity, specificity, and concordance statistics were calculated to evaluate its diagnostic performance. RESULTS: The formula for calculating the probability of pathological lymph node metastasis included SUVmax of the primary tumor and serum CEA level. The concordance statistics was 0.7452. When the cutoff value associated with the risk of incorrectly predicting pathological lymph node metastasis was 7.2%, the diagnostic sensitivity and specificity for predicting metastasis were 96.4% and 38.6%, respectively. CONCLUSIONS: We created a prediction model for lymph node metastasis in NSCLC by combining the SUVmax of the primary tumor and serum CEA levels, which showed a particularly strong association. This model is clinically useful as it successfully predicts negative lymph node metastasis in patients with clinical stage IA2-3 NSCLC.

The significance of regular chest computed tomography in postoperative surveillance for surgically resected non-small cell lung cancer based on TNM 8th staging system.

OBJECTIVES: Although several societies recommend regular chest computed tomography (CT) scans for the surveillance of surgically resected non-small cell lung cancer (NSCLC), there is paucity of evidence to support these statements. This study aimed to clarify whether regular CT scans improved the prognosis of patients with surgically resected NSCLC based on TNM 8th classification. METHODS: Patients with pathologic Stage 0-III NSCLC who underwent complete surgical resection other than sublobar resection procedures were enrolled in the study. For these patients, clinicopathological data and postoperative surveillance data were collected by the retrospective review of medical records. Patients were categorized into the chest X-ray (CXR) group or the CT group according to whether they were followed-up with basic examinations including CXR or basic examinations plus regular chest CT. Postoperative overall survival was compared between the two groups. RESULTS: Six hundred sixty five patients were categorized into the CXR (n = 245) and CT (n = 420) groups. The clinicopathological backgrounds did not differ to a statistically significant extent. Recurrence was seen in 68 (27.3%) patients in the CXR group and 117 (27.8%) patients in the CT group. The 5-year overall survival rates of the two groups did not differ to a statistically significant extent (CXR, 76.5%; CT, 78.3%, P = 0.22). CONCLUSION: Regular chest CT scans may not improve the prognosis of surgically resected NSCLC. Further study is warranted to precisely evaluate the benefit of CT-based postoperative surveillance of NSCLC.

The prognostic impact of a high number of peritumoral alveolar macrophages in neuroendocrine carcinoma in the lung.

Alveolar macrophages (AMs) are resident macrophages in the lungs; however, whether the number of AMs plays a role in the lung neuroendocrine tumor (NET) prognosis remains unclear. We counted the number of AMs located around the tumor (peritumoral alveolar macrophages [pAMs]) and the number of AMs located apart from the tumor (distant macrophages; dAMs). In 73 cases of neuroendocrine carcinoma (NEC: small cell lung carcinoma and large cell neuroendocrine carcinoma), the group that contained higher pAMs (≥86/µm2 ) revealed shorter recurrent-free survival (RFS) than those with lower pAMs (<86/µm2 ) (p = 0.005). Bivariate analysis showed that the number of pAMs was an independent predictor of a poor RFS. In contrast, in the carcinoid tumor cohort (n = 29), there was no statistically significant correlation between the two groups with high and low numbers of pAMs in RFS (p = 0.113). Furthermore, we examined the correlation between genomic alterations and the number of pAMs in NEC, but no significant correlation was observed. In conclusion, the number of pAMs is a prognostic factor for NEC in the lung and pAMs may contribute to tumor progression within the peritumoral microenvironment.

Efficacy of Preoperative Biopsy in Predicting the Newly Proposed Histologic Grade of Resected Lung Adenocarcinoma.

A novel histologic grading system for invasive lung adenocarcinomas (LUAD) has been newly proposed and adopted by the World Health Organization (WHO) classification. We aimed to evaluate the concordance of newly established grades between preoperative biopsy and surgically resected LUAD samples. Additionally, factors affecting the concordance rate and its prognostic impact were also analyzed. In this study, surgically resected specimens of 222 patients with invasive LUAD and their preoperative biopsies collected between January 2013 and December 2020 were used. We determined the histologic subtypes of preoperative biopsy and surgically resected specimens and classified them separately according to the novel WHO grading system. The overall concordance rate of the novel WHO grades between preoperative biopsy and surgically resected samples was 81.5%, which was higher than that of the predominant subtype. When stratified by grades, the concordance rate of grades 1 (well-differentiated, 84.2%) and 3 (poorly differentiated, 89.1%) was found to be superior compared to grade 2 (moderately differentiated, 66.2%). Overall, the concordance rate was not significantly different from biopsy characteristics, including the number of biopsy samples, biopsy sample size, and tumor area size. On the other hand, the concordance rate of grades 1 and 2 was significantly higher in tumors with smaller invasive diameters, and that of grade 3 was significantly higher in tumors with larger invasive diameters. Preoperative biopsy specimens can predict the novel WHO grades, especially grades 1 and 3 of surgically resected specimens, more accurately than the former grading system, regardless of preoperative biopsy or clinicopathologic characteristics.

Long-term survival outcomes after lobe-specific nodal dissection in patients with early non-small-cell lung cancer.

OBJECTIVES: We investigated the long-term outcomes of lobe-specific nodal dissection (LSD) and systematic nodal dissection (SND) in patients with non-small-cell lung cancer (NSCLC). METHODS: Patients with c-stage I and II NSCLC who underwent lobectomy with mediastinal nodal dissection were retrospectively analysed. After propensity score matching, we assessed the overall survival (OS), recurrence-free survival (RFS) and cumulative incidence of death (CID) from primary lung cancer and other diseases. RESULTS: The median follow-up period was 8.4 years. Among 438 propensity score-matched pairs, OS and RFS were similar between the LSD and SND groups [hazard ratio (HR), 0.979; 95% confidence interval (CI), 0.799-1.199; and HR, 0.912; 95% CI, 0.762-1.092, respectively], but the LSD group showed a better prognosis after 5 years postoperatively. CID from primary lung cancer was similar between the 2 groups (HR, 1.239; 95% CI, 0.940-1.633). However, the CID from other diseases was lower in the LSD group than in the SND group (HR, 0.702; 95% CI, 0.525-0.938). According to c-stage, the LSD group tended towards worse OS and RFS, with higher CID from primary lung cancer than the SND group, in patients with c-stage II. CONCLUSIONS: LSD provides acceptable long-term survival for patients with early-stage NSCLC. However, LSD may not be suitable for patients with c-stage II NSCLC due to the higher mortality risk from primary lung cancer.

Comparison of various lung intersegmental plane identification methods.

Keeping a sufficient surgical margin free of tumor is important to prevent local recurrence in lung segmentectomy. Accurate identification of the intersegmental plane is essential to achieve adequate surgical margins. Traditionally, the inflation-deflation method was used to identify the intersegmental plane. However, in recent years, various intersegmental plane identification methods, including systemic indocyanine green injection, have been reported and shown to be useful. The purpose of this review was to evaluate the identification rates, advantages, and disadvantages of various intersegmental identification methods in lung segmentectomy. There are primarily six methods: inflation-deflation method, selective segmental inflation, endobronchial dye injection, virtual-assisted lung mapping, systemic indocyanine green injection, and pure oxygen method. These are broadly classified into those that use bronchi and pulmonary arteries anatomically and those that use air and dye technically. In this review, all methods showed relatively high identification rates. Moreover, high identification rates were expected, especially with systemic indocyanine green injection and the pure oxygen method. Each method has its advantages and disadvantages as varying situations entail different methods. It is necessary to select and apply them effectively; therefore, further improvement for each method will be required in the future.

Clinicopathological features and prognostic impact of dirty necrosis in metastatic lung cancers from the colon and rectum.

Dirty necrosis (DN) is a form of tumor necrosis (TN) with prominent neutrophil infiltration and cell detritus in the necrotic foci. This study aimed to characterize the clinicopathological features of DN in metastatic lung cancers of the colon and rectum (MLCRs). A total of 227 patients who underwent pulmonary metastasectomy and complete resection for MLCR were included in this study. TN was evaluated using digitally scanned resection specimens. These slides were immunostained for biomarkers of NETosis (citrullinated histone H3 [citH3] and myeloperoxidase [MPO]), and the area positive for citH3 and MPO was further quantified. TN was observed in 216 cases (95.2%), and 54 (25.0%) of these cases had DN. The presence of TN was not associated with a worse prognosis; however, patients with DN had a significantly shorter overall survival than those without DN (p < 0.01). Furthermore, the presence of DN was a poor prognostic factor in both the univariate and multivariate analyses. Immunohistochemical analysis revealed that the percentage of citH3-positive and MPO-positive areas in the DN-positive cases was significantly higher than that in the DN-negative cases (p < 0.01 and p < 0.01, respectively). In surgically resected MLCR, DN is the characteristic TN subtype associated with poor prognosis and neutrophil extracellular traps (NETs).