Recent advances and clinical implications of the micropapillary histological subtype in lung adenocarcinomas

Evaluation of the preoperative neutrophil-to-lymphocyte ratio as a predictor of the micropapillary component of stage IA lung adenocarcinoma

OBJECTIVE

To assess the ability of markers of inflammation to identify the solid or micropapillary components of stage IA lung adenocarcinoma and their effects on prognosis.

METHODS

We performed a retrospective study of clinicopathologic data from 654 patients with stage IA lung adenocarcinoma collected between 2013 and 2019. Logistic regression analysis was used to identify independent predictors of these components, and we also evaluated the relationship between markers of inflammation and recurrence.

RESULTS

Micropapillary-positive participants had high preoperative neutrophil-to-lymphocyte ratios. There were no significant differences in the levels of markers of systemic inflammation between the participants with or without a solid component. Multivariate analysis showed that preoperative neutrophil-to-lymphocyte ratio (odds ratio [OR] = 2.094; 95% confidence interval [CI], 1.668-2.628), tumor size (OR = 1.386; 95% CI, 1.044-1.842), and carcinoembryonic antigen concentration (OR = 1.067; 95% CI, 1.017-1.119) were independent predictors of a micropapillary component. There were no significant correlations between markers of systemic inflammation and the recurrence of stage IA lung adenocarcinoma.

CONCLUSIONS

Preoperative neutrophil-to-lymphocyte ratio independently predicts a micropapillary component of stage IA lung adenocarcinoma. Therefore, the potential use of preoperative neutrophil-to-lymphocyte ratio in the optimization of surgical strategies for the treatment of stage IA lung adenocarcinoma should be further studied.

Micropapillary or solid component predicts worse prognosis in pathological IA stage lung adenocarcinoma: A meta-analysis

BACKGROUND

Micropapillary and solid patterns indicate worse survival in lung adenocarcinoma patients, even in pathological stage IB patients. However, whether the presence of micropapillary or solid components is related to worse prognosis in pathological IA stage lung adenocarcinoma remains unclear.

METHODS

Several databases were searched up to December 31, 2022 for relevant studies investigating the association between micropapillary and solid components and the survival of IA stage lung adenocarcinoma patients. Primary and secondary outcomes are disease-free survival (DFS) and overall survival (OS), respectively. Hazard ratios (HRs) and 95% confident intervals (CIs) were combined, and subgroup analysis stratified by the pathological subtype and proportion of components was further performed.

RESULTS

A total of 19 studies with 12,562 cases were included. Pooled results indicated that micropapillary or solid components obviously predicted worse DFS (HR = 2.40, 95% CI: 1.96-2.94, P < .001) and OS (HR = 2.30, 95% CI: 1.68-3.15, P < .001). Subgroup analysis based on pathological subtype showed that both micropapillary and solid components were significantly associated with worse DFS (micropapillary: HR = 2.70, 95% CI: 1.70-4.28, P < .001; solid: HR = 3.98, 95% CI: 2.10-7.54, P < .001) and OS (micropapillary: HR = 2.29, 95% CI: 1.17-4.48, P = .015; solid: HR = 4.18, 95% CI: 1.72-10.17, P = .002). In addition, further subgroup analysis stratified by the proportion of micropapillary and solid components (>5%/1% or predominant) showed similar results.

CONCLUSION

Micropapillary and solid patterns predicted a significantly worse prognosis in pathological IA stage lung adenocarcinoma patients.

Factors associated with lymph node metastasis upstage after resection for patients with micropapillary lung adenocarcinoma

Background

Micropapillary adenocarcinoma has a poor prognostic histological pattern. Additionally, preoperative detection of lymph node metastases by preoperative examination is difficult in some patients with micropapillary adenocarcinoma, and postoperative upstage may occur. However, clinicopathological features of patients with micropapillary adenocarcinoma with nodal upstage have not been established, therefore this study aimed to identify the factors associated with potential lymph node metastases during preoperative examination to ensure effective surgical procedures.

Methods

Between January 2011 and December 2020, 1029 patients received complete resection for primary non‐small‐cell lung cancer by lobectomy or more extensive resection with systematic lymph node dissection at this institution. One hundred and thirty‐one patients diagnosed with adenocarcinoma with micropapillary component were included in this study. The clinicopathological features of patients with nodal upstage whose postoperative N stage was more advanced than the preoperative N stage were examined.

Results

Forty patients had nodal upstage after resection. ¹⁸F‐fluorodeoxyglucose (FDG) positron emission tomography‐computed tomography (PET‐CT) revealed that a maximum standardized uptake value (SUVmax) ≥5 for the primary lesion was significantly associated with postoperative nodal upstage. There were no significant differences in terms of sex, age, smoking history, surgical procedure, and diabetes. Among 38 patients with nodal upstage, 23 patients had no significant preoperative lymphadenopathy and showed no abnormal FDG uptake in the lymph nodes on ¹⁸F‐FDG‐PET‐CT, respectively.

Conclusions

Lymph node metastases were suspected in patients preoperatively diagnosed with micropapillary adenocarcinoma with FDG SUVmax ≥5 for the primary tumor. Therefore, standard surgical resection and careful lymph node dissection should be performed for such patients.

Micropapillary adenocarcinoma of lung: Morphological criteria and diagnostic reproducibility among pulmonary pathologists

CONTEXT

Invasive micropapillary adenocarcinoma (MPC) is an aggressive variant of lung adenocarcinoma, frequently manifesting with advanced stage lymph node metastasis and decreased survival.

OBJECTIVE

Identification of this morphology is important, as it is strongly correlated with poor prognosis regardless of the amount of MPC component. To date, no study has investigated the morphological criteria used to objectively diagnose it.

DESIGN

Herein, we selected 30 cases of potential MPC of lung, and distributed 2 digital images per case among 15 pulmonary pathology experts. Reviewers were requested to diagnostically interpret, assign the percentage of MPC component, and record the morphological features they identified. The noted features included: columnar cells, elongated slender cell nests, extensive stromal retraction, lumen formation with internal epithelial tufting, epithelial signet ring-like forms, intracytoplasmic vacuolization, multiple nests in the same alveolar space, back-to-back lacunar spaces, epithelial nest anastomosis, marked pleomorphism, peripherally oriented nuclei, randomly distributed nuclei, small/medium/large tumor nest size, fibrovascular cores, and spread through air-spaces (STAS).

RESULTS

Cluster analysis revealed three subgroups with the following diagnoses: "MPC", "combined papillary and MPC", and "others". The subgroups correlated with the reported median percentage of MPC. Intracytoplasmic vacuolization, epithelial nest anastomosis/confluence, multiple nests in the same alveolar space, and small/medium tumor nest size were the most common criteria identified in the cases diagnosed as MPC. Peripherally oriented nuclei and epithelial signet ring-like forms were frequently identified in both the "MPC" and "combined papillary and MPC" groups.

CONCLUSIONS

Our study provides objective diagnostic criteria to diagnose MPC of lung.

The more the micropapillary pattern in stage I lung adenocarcinoma, the worse the prognosis-a retrospective study on digitalized slides

Although the majority of lung adenocarcinomas show mixed pattern, only the predominant component is taken into account according to the novel classification. We evaluated the proportion of different patterns and their impact on overall survival (OS) and disease-free survival (DFS). Patterns were recorded according to predominance and their proportions were rated and calculated by objective area measuring on digitalized, annotated slides of resected stage I lung adenocarcinomas. Spearman's rank correlation, Kaplan-Meier models and the log rank test were used for statistical evaluation. Two hundred forty-three stage I adenocarcinoma were included. Lepidic pattern is more frequent in tumours without recurrence (20 vs. 8%), and lepidic predominant tumours have favourable prognosis (OS 90.5%, DFS 89.4%), but proportions above 25% are not associated with improving outcome. Solid and micropapillary patterns are more frequent in patients with recurrence (48 vs. 5% and 13 vs. 4%) and predominance of each one is associated with unfavourable prognosis (OS 64.1%, DFS 56.3% and OS 28.1%, DFS 28.1%, respectively). Above 25%, a growing proportion of solid or micropapillary pattern is not associated with worsening prognosis. In contrast, tumours having micropapillary pattern as secondly predominant form a different intermediate group (OS 51.1%, DFS 57.8%). Our study was based on measured area of each growth pattern on all available slides digitalized. This is the most precise way of determining the size of each component from the material available. We propose using predominant and secondly predominant patterns for prognostic purposes, particularly in tumours having solid or micropapillary patterns.

Uniportal video-assisted thoracoscopic anatomic segmentectomy for small-sized lung cancer

Increasing evidences prove video-assisted thoracic surgery (VATS) segmentectomy is accepted as a valid alternative to lobectomy esp. a greater number of small lung nodules have been detected. Uniportal VATS segmentectomy for small-sized lung cancer is more challenging not only for technical issues in simple or complex uniportal segmentectomy, but also considering oncological efficacy in terms of localization, safe margin, the extent of lymph node dissection and pathological analysis. In this work, we evaluated our evolving uniportal experience, the surgical technique and decision-making of uniportal VATS segmentectomy for small-sized lung cancer.

Evaluation of grading systems in stage I lung adenocarcinomas: a retrospective cohort study

AIMS

There is no internationally accepted grading system for lung adenocarcinoma despite the new WHO classification. The architectural grade, the Kadota grade and the Sica score were evaluated and compared with overall (OS) and disease-free survival (DFS).

METHODS

Comprehensive histological subtyping was used in a series of resected stage I lung adenocarcinoma to identify subtypes of adenocarcinomas, the architectural grade, the Kadota grade, the Sica grade, the mitotic count, nuclear atypia, the presence of lymphovascular, vascular and airway propagation, necrosis, and micropapillary or solid growth pattern in any percentage. Statistical models fitted included Kaplan-Meier estimates and Cox proportional hazard regression models.

RESULTS

261 stage I adenocarcinomas were included. The 5-year survivals of different subtypes were as follows: lepidic (n=40, OS: 92.5%; DFS 91.6%), acinar (n=54, OS: 81.8%; DFS: 68.6%), papillary (n=49, OS: 73.6%; DFS: 61.0%), solid (n=95, OS: 64.7%; DFS: 57.8%) and micropapillary (n=23, OS: 34.8%; DFS: 33.5%). Concerning the architectural grade, there were significant differences between OS and DFS of low and intermediate (pOS=0.005, pDFS<0.001), low and high (pOS<0.001, pDFS<0.001) and intermediate and high grades (pOS=0.002, pDFS<0.001). Low-grade and intermediate grade tumours did not differ in survival according to Kadota grade and Sica grade. In the multivariable model, architectural grade was found to be an independent prognostic marker. In another model, architectural pattern proved to be superior to architectural grade.

CONCLUSIONS

Of the three grading systems compared, the architectural grade makes the best distinction between the outcome of low-grade, intermediate-grade and high-grade stage I adenocarcinomas.

Clinical impacts of a micropapillary pattern in lung adenocarcinoma: a review

Lung adenocarcinoma with a micropapillary pattern (MPPAC) has recently drawn increased attention among researchers. Micropapillary-predominant adenocarcinoma (MPA), which is defined by micropapillary pattern (MPP), is the primary histological pattern observed semiquantitatively in 5% increments on resection specimens, and MPA was formally determined to be a new histological subtype according to the new multidisciplinary classification in 2011. According to published studies, MPPAC is most common in males and nonsmokers and is associated with lymphatic invasion, pleural invasion, and lymph node metastases. MPPAC often presents as part-solid and lobulated nodules in computed tomography scans. MPP tends to have a higher maximum standardized uptake value as determined by fluorodeoxyglucose positron emission tomography combined with computed tomography, indicating a high risk of recurrence. Molecular markers, including vimentin, napsin A, phosphorylated c-Met, cytoplasmic maspin, Notch-1, MUC1, and tumoral CD10, may have higher expression in MPPAC than other subtypes; conversely, markers such as MUC4 and surfactant apoprotein A have lower expression in MPPAC. MPPAC with EGFR mutations can benefit from treatment with EGFR tyrosine kinase inhibitors. Furthermore, a complete lobectomy may be more suitable than limited resection for MPPAC because of the low sensitivity of intraoperative frozen sections and the high risk of lymph node metastasis. MPA benefits more from adjuvant chemotherapy than do other histological subtypes, whereas MPA does not benefit from adjuvant radiotherapy. Of note, MPP is associated with poor prognosis in early-stage lung adenocarcinoma, but the prognostic value of MPP is controversial in advanced-stage lung adenocarcinoma.