2021 WHO Classification of Lung Cancer: Molecular Biology Research and Radiologic-Pathologic Correlation

The 2021 World Health Organization (WHO) classification system for thoracic tumors (including lung cancer) contains several updates to the 2015 edition. Revisions for lung cancer include a new grading system for invasive nonmucinous adenocarcinoma that better reflects prognosis, reorganization of squamous cell carcinomas and neuroendocrine neoplasms, and description of some new entities. Moreover, remarkable advancements in our knowledge of genetic mutations and targeted therapies have led to a much greater emphasis on genetic testing than that in 2015. In 2015, guidelines recommended evaluation of only two driver mutations, ie, epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) fusions, in patients with nonsquamous non-small cell lung cancer. The 2021 guidelines recommend testing for numerous additional gene mutations for which targeted therapies are now available including ROS1, RET, NTRK1-3, KRAS, BRAF, and MET. The correlation of imaging features and genetic mutations is being studied. Testing for the immune biomarker programmed death ligand 1 is now recommended before starting first-line therapy in patients with metastatic non-small cell lung cancer. Because 70% of lung cancers are unresectable at patient presentation, diagnosis of lung cancer is usually based on small diagnostic samples (ie, biopsy specimens) rather than surgical resection specimens. The 2021 version emphasizes differences in the histopathologic interpretation of small diagnostic samples and resection specimens. Radiologists play a key role not only in evaluation of tumor and metastatic disease but also in identification of optimal biopsy targets. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Exploring the molecular features and genetic prognostic factors of pulmonary high-grade neuroendocrine carcinomas

Molecular research on large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC) has progressed significantly. However, there are still fewer molecular markers related to prognostic/therapeutic strategies for these conditions compared to those for adenocarcinoma. We therefore investigated the molecular characteristics of neuroendocrine carcinomas (NECs). We enrolled patients surgically diagnosed with NECs between 2011 and 2019, with complete follow-up records. All were analyzed using whole exome sequencing and p53/Rb immunohistochemistry (IHC). A total of 92 cases, comprising 45 pure SCLC, 15 combined SCLC, 27 pure LCNEC, and 5 combined LCNEC, were included. TP53 (78.3%) and RB1 (34.8%) were the most common molecular alterations, followed by KMT2D, LRP1B, FAT3, NCOR2, SPTA1, and NOTCH1. The mutation frequency for EGFR was 10.9%. Sixteen patients with LCNEC who had TP53/RB1 co-alterations were SCLC-like, while the remaining were NSCLC-like. There was no statistically significant difference between the groups regarding overall survival (OS; p = 0.458) and progression-free survival (PFS; p = 0.157). The frequency of the loss of Rb expression by IHC in SCLC-like LCNEC was 100%. Significant pathway alterations unique to SCLC included Notch and AMPK, while HIF-1 was enriched exclusively in LCNEC. NCOR2 mutation was linked to worse OS (p = 0.029) and PFS (p = 0.015), while wild-type SPTA1 was associated with poor PFS (p = 0.018). IHC for Rb was reliable for predicting LCNEC molecular subtypes, indicating its clinical value. NCOR2 and SPTA1 alterations were identified as prognostic factors that may provide therapeutic targets for patients with NEC.

Survival of small-cell lung cancer patients after surgery: A single-center retrospective cohort study

This study summarized and analyzed the clinical characteristics and prognosis of small-cell lung cancer (SCLC) patients after surgical treatment. The clinical data of 130 patients (99 males and 31 females) with SCLC treated by surgery and confirmed by postoperative pathological examination at Peking Union Medical College Hospital from April 2004 to April 2019 were retrospectively analyzed. Clinical characteristics, surgery, pathological stage, and perioperative treatment were summarized. Kaplan-Meier survival curve and Cox regression analysis were performed. Pathological examination revealed that 36 (27.69%) patients had stage I SCLC, 22 (16.92%) patients had stage II SCLC, 65 (50.00%) patients had stage III SCLC, and 7 (5.39%) patients had stage IV SCLC. The overall median survival time was 50 months (95% confidence interval, 10.8-89.2 months). The median survival time of stage I, II, III and IV SCLC patients was 148, 42, 32, and 10 months, respectively. In patients who underwent surgical treatment, postoperative adjuvant therapy and tumor stage were independent prognostic factors for survival (p < 0.05).Lobectomy and lymph nodes resection combined with adjuvant therapy were cautiously recommended for stage I-IIIa SCLC patients.

A nomogram diagnostic prediction model of pancreatic metastases of small cell lung carcinoma based on clinical characteristics, radiological features and biomarkers

Objective

To investigate clinical characteristics, radiological features and biomarkers of pancreatic metastases of small cell lung carcinoma (PM-SCLC), and establish a convenient nomogram diagnostic predictive model to differentiate PM-SCLC from pancreatic ductal adenocarcinomas (PDAC) preoperatively.

Methods

A total of 299 patients with meeting the criteria (PM-SCLC n=93; PDAC n=206) from January 2016 to March 2022 were retrospectively analyzed, including 249 patients from hospital 1 (training/internal validation cohort) and 50 patients from hospital 2 (external validation cohort). We searched for meaningful clinical characteristics, radiological features and biomarkers and determined the predictors through multivariable logistic regression analysis. Three models: clinical model, CT imaging model, and combined model, were developed for the diagnosis and prediction of PM-SCLC. Nomogram was constructed based on independent predictors. The receiver operating curve was undertaken to estimate the discrimination.

Results

Six independent predictors for PM-SCLC diagnosis in multivariate logistic regression analysis, including clinical symptoms, CA199, tumor size, parenchymal atrophy, vascular involvement and enhancement type. The nomogram diagnostic predictive model based on these six independent predictors showed the best performance, achieved the AUCs of the training cohort (n = 174), internal validation cohort (n = 75) and external validation cohort (n = 50) were 0.950 (95%CI, 0.917-0.976), 0.928 (95%CI, 0.873-0.971) and 0.976 (95%CI, 0.944-1.00) respectively. The model achieved 94.50% sensitivity, 83.20% specificity, 86.80% accuracy in the training cohort and 100.00% sensitivity, 80.40% specificity, 86.70% accuracy in the internal validation cohort and 100.00% sensitivity, 88.90% specificity, 87.50% accuracy in the external validation cohort.

Conclusion

We proposed a noninvasive and convenient nomogram diagnostic predictive model based on clinical characteristics, radiological features and biomarkers to preoperatively differentiate PM-SCLC from PDAC.

Different clinical characteristics and survival between surgically resected pure and combined small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is the most malignant and common form of neuroendocrine lung cancer with pure (P-SCLC) and combined subtypes (C-SCLC). However, little is known about the differences between these two groups and in this study we aimed to provide a more comprehensive insight into SCLC.

METHODS

Data from 580 postoperative patients with pathologically confirmed SCLC in Shanghai Chest Hospital from January 2010 to December 2020 were collected retrospectively. The clinical characteristics and prognosis were analyzed.

RESULTS

A total of 357 P-SCLC patients and 223 C-SCLC patients were included. The results indicated that P-SCLC appeared to have a higher proportion of being located in the middle lobe than C-SCLC. The incidences of P-SCLC in patients with visceral pleural invasion (VPI) and in stage II were higher than C-SCLC, while C-SCLC was more likely to be accompanied by higher incidences of epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) rearrangement, and higher levels of CEA, SCCA and CYFRA21-1 than P-SCLC. The most common were SCLC combined with large cell neuroendocrine components among 223 C-SCLCs. Survival analysis confirmed a more favorable disease-free survival (DFS) (p = 0.016) and overall survival (OS) (p = 0.024) in patients with P-SCLCs compared with C-SCLCs. Histological type, tumor location, pN stage, adjuvant chemotherapy, serum NSE and CA125 levels were independent risk factors for survival rate in SCLC. In addition, adjuvant chemotherapy was beneficial in improving stage I P-SCLC and C-SCLC DFS and OS rates, and similar results were not seen in adjuvant radiation therapy.

CONCLUSIONS

Patients with C-SCLC have a poorer prognosis than P-SCLC patients. We determined that large cell neuroendocrine carcinoma was the most common additional component of C-SCLC, and patients with this component appeared to have a longer DFS and OS than other combined components.

Primary tumor location in lung cancer: the evaluation and administration

ABSTRACT

Lung cancer continues to be the leading cause of cancer-related death in the world, which is classically subgrouped into two major histological types: Non-small cell lung cancer (NSCLC) (85% of patients) and small-cell lung cancer (SCLC) (15%). Tumor location has been reported to be associated with the prognosis of various solid tumors. Several types of cancer often occur in a specific region and are more prone to spread to predilection locations, including colorectal cancer, prostate cancer, gastric cancer, ovarian cancer, cervical cancer, bladder cancer, lung tumor, and so on. Besides, tumor location is also considered as a risk factor for lung neoplasm with chronic obstructive pulmonary disease/emphysema. Additionally, the primary lung cancer location is associated with specific lymph node metastasis. And the recent analysis has shown that the primary location may affect metastasis pattern in metastatic NSCLC based on a large population. Numerous studies have enrolled the "location" factor in the risk model. Anatomy location and lobe-specific location are both important in prognosis. Therefore, it is important for us to clarify the characteristics about tumor location according to various definitions. However, the inconsistent definitions about tumor location among different articles are controversial. It is also a significant guidance in multimode therapy in the present time. In this review, we mainly aim to provide a new insight about tumor location, including anatomy, clinicopathology, and prognosis in patients with lung neoplasm.

Prognostic factors of patients with small cell lung cancer after surgical treatment

Background

The current National Comprehensive Cancer Network guidelines recommend surgical treatment for patients with stages I–IIA small cell lung cancer (SCLC), but it still cannot deny the effect of surgical treatment on other limited-stage SCLC. Although more advanced diagnostic methods are now used for the diagnosis and classification of SCLC, the selection of surgical candidates is still arbitrary.

Methods

Data were collected from patients with SCLC who underwent surgery at the First Affiliated Hospital of Zhengzhou University from January 2011 to January 2021. Kaplan-Meier method was used to calculate cumulative survival curves, and log-rank test was used to evaluate differences among different subgroups. The Cox proportional hazard regression model was used to assess the predictive power of the variables for prognosis and survival.

Results

Smoking index, surgical resection method, TNM stage of postoperative pathology, and postoperative chemotherapy were significantly correlated with postoperative survival (P<0.05), which were independent predictors for postoperative survival. Patients with a smoking index >800 had a higher risk of death after surgery [hazard ratio (HR): 7.050, 95% confidence interval (CI): 3.079–16.143, P<0.001]. Compared with patients who underwent pulmonary lobectomy, those who underwent other pneumoresections (e.g., wedge resection, segmental resection, sleeve resection) had an increased risk of death (HR: 2.822, 95% CI: 1.030–7.734, P=0.044). Compared with stage I patients, stage II and stage III patients had an increased risk of death, with HRs of 6.039 and 3.145, respectively. Compared with those who received ≤4 courses of postoperative chemotherapy, those who received >4 courses of postoperative chemotherapy had reduced postoperative mortality risk (HR: 0.211, 95% CI: 0.097–0.459, P<0.001).

Conclusions

A high smoking index suggests worse prognosis; therefore, patients who smoke should be advised to quit smoking. Compared with stage II and stage III patients, surgical treatment is recommended for stage I SCLC patients. TNM staging, especially N staging, should be evaluated prior to surgery. Pulmonary lobectomy with mediastinal lymph node dissection should be the preferred surgical treatment for patients with SCLC. Patients should receive at least 5 courses of adjuvant chemotherapy after surgery.

Clinical Behavior of Combined Versus Pure High-Grade Neuroendocrine Carcinoma

BACKGROUND

The aim of this study was to investigate and compare the clinical behaviors of combined and pure high-grade neuroendocrine carcinoma (large-cell neuroendocrine carcinoma [LCNEC] and small-cell lung carcinoma [SCLC]).

PATIENTS AND METHODS

Data of 132 patients who underwent complete resection for combined or pure high-grade neuroendocrine carcinoma (combined group, 67; pure group, 65) between January 2001 and December 2015 were retrospectively reviewed. The clinicopathological features were analyzed and compared, and the prognoses were assessed by performing the Kaplan-Meier method and Cox regression analysis.

RESULTS

The combined and pure groups had nearly equivalent clinicopathological characteristics, specifically, older males with smoking history, almost the same percentage of pleural/lymphatic/vascular invasion, and nearly the same recurrence rates and relapse patterns. The combined group had prognosis equivalent to that of the pure group (5-year overall survival [OS] rates: 61.8% vs. 52.2%, respectively; P = .82 and 5-year recurrence-free survival [RFS] rates: 42.4% vs. 43.9%, respectively; P = .96), and this trend was identified in sub-analyses only for patients with LCNEC, SCLC, and the same pathological stage. Multivariable Cox regression analysis in patients with high-grade neuroendocrine carcinoma revealed that vascular invasion and pathological stage were independent prognostic factors for OS; more importantly, combined and pure histologies were proven to have nearly equivalent associations with prognosis (hazard ratio, 0.96; 95% confidence interval, 0.22to 1.66; P = .96).

RESULTS

Combined high-grade neuroendocrine carcinoma had clinical behavior equivalent to those of pure high-grade neuroendocrine carcinoma, with similar clinicopathological characteristics.

Clinical characteristics and prognostic factors of surgically resected combined small cell lung cancer: a retrospective study

OBJECTIVES

Small cell lung cancer (SCLC) is the most malignant lung cancer. Some of them are mixed with non-small cell lung cancer(NSCLC, Non SCLC),which are called combined small cell lung cancer (C-SCLC).Due to the difficulty of pathological diagnosis and the complexity of treatment, studies of C-SCLC have just been rising in recent years. This study is to evaluate the clinical and pathologic characteristics of C-SCLC.

METHODS

Stage Ⅰ-Ⅲa C-SCLC patients who received radical R0 surgery between 2009-2018 in Shanghai Chest Hospital were enrolled. Clinical characteristics and prognosis were analyzed.

RESULTS

Totally 181 patients were included, most of them were small cell combined with large cell neuroendocrine components(SCLC/LCNEC,58.0 %,N = 105),then with adenocarcinoma(SCLC/ADC:13.8 %,N = 25),and finally with squamous cell carcinoma(SCLC/SCC:13.3 %,N = 24).Median DFS and OS of C-SCLC patients underwent radical surgery were 32.5 and 49.7 months.1,3 and 5 years DFS rates of the entire cohort were 68.5 %,32.6 % and 16.0 %,respectively. Patients with SCLC/LCNEC had longer DFS (44.1 m vs. 20.4 m, p = 0.040) and longer OS trend (62.1 m vs. 33.2 m, p = 0.122).Groups of whether tumor invaded the pleura(p = 0.028 and p = 0.050),lymph node stage(p = 0.029 and p = 0.010) and the courses of adjuvant chemotherapy(p = 0.011 and p = 0.001) had statistical differences on DFS and OS.

CONCLUSIONS

SCLC/LCNEC was the most common type of C-SCLC. Patients' DFS and OS were also longer than other combined types. Adjuvant chemotherapy for SCLC is still the main treatment for surgical C-SCLC. Further studies are needed to clarify the clinical characteristics and prognosis of C-SCLC.