Distinct clinicopathologic features, genomic characteristics and survival of central and peripheral pulmonary large cell neuroendocrine carcinoma: From different origin cells?

The Correlation Between Histologic, Immunophenotypic, and Molecular Characteristics of Pulmonary Sarcomatoid Carcinoma Reveals That Sarcomatoid Change Is Potentially Derived From Epithelial Carcinoma Cells Undergoing Epithelial-Mesenchymal Transition

Pulmonary sarcomatoid carcinoma (PSC) is characterized by biphasic tumors with epithelial and mesenchymal phenotype. Little is known about the correlation between histologic, immunophenotypic features and the genetic profile of PSC. We analyzed the expression of epithelial-mesenchymal transition-related markers, adenocarcinoma (ADC) and squamous cell carcinoma lineage-specific markers of 205 PSC cases. The alteration of 5 targeted genes was detected by amplification-refractory mutation system-polymerase chain reaction. The intensity of cytokeratin staining was stronger in epithelial carcinoma (EC) than that of the sarcomatoid component (SC) of pleomorphic carcinoma, while vimentin was positive in only 16.3% (17/104) of EC of pleomorphic carcinoma. There is no significant difference between thyroid transcription factor 1 (TTF-1) expression in the SC (46.5%, 33/71) of pleomorphic carcinoma with ADC components and pure PSC (44.2%, 42/95) without p40 expression ( P =0.858). Four cases with ALK rearrangement were confirmed to co-express ALK fusion protein in both the SC and EC. The incidence of EGFR/ALK/KRAS mutation was similar between pleomorphic carcinoma with ADC components (40.6%, 26/64) and TTF-1 + pure PSC (38.2%, 13/34) ( P =0.583). However, higher proportions of TTF-1 + /p40 - PSC patients (44.8%, 39/87) had EGFR/ALK/KRAS mutation than those with TTF-1 - /p40 - PSC (16.7%, 4/24) ( P =0.031). The incidence of EGFR mutation was significantly higher in TTF-1-positive (18.4%, 16/87) than TTF-1-negative (2.7%, 2/74) PSC ( P =0.002). No EGFR and ALK abnormality were observed in 24 pleomorphic carcinoma cases with squamous cell carcinoma components or pure PSC with p40 expression. Our study reveals a close correlation between SC and EC components of pleomorphic carcinoma in terms of immunophenotypic and genetic features, which suggests that pleomorphic carcinoma is potentially derived from the sarcomatoid change of EC cells undergoing epithelial-mesenchymal transition.

Prognostic Factors across Poorly Differentiated Neuroendocrine Neoplasms: A Pooled Analysis

INTRODUCTION

Poorly differentiated neuroendocrine carcinomas (NECs) are characterized by aggressive clinical course and poor prognosis. No reliable prognostic markers have been validated to date; thus, the definition of a specific NEC prognostic algorithm represents a clinical need. This study aimed to analyze a large NEC case series to validate the specific prognostic factors identified in previous studies on gastro-entero-pancreatic and lung NECs and to assess if further prognostic parameters can be isolated.

METHODS

A pooled analysis of four NEC retrospective studies was performed to evaluate the prognostic role of Ki-67 cut-off, the overall survival (OS) according to primary cancer site, and further prognostic parameters using multivariable Cox proportional hazards model and machine learning random survival forest (RSF).

RESULTS

422 NECs were analyzed. The most represented tumor site was the colorectum (n = 156, 37%), followed by the lungs (n = 111, 26%), gastroesophageal site (n = 83, 20%; 66 gastric, 79%) and pancreas (n = 42, 10%). The Ki-67 index was the most relevant predictor, followed by morphology (pure or mixed/combined NECs), stage, and site. The predicted RSF response for survival at 1, 2, or 3 years showed decreasing survival with increasing Ki-67, pure NEC morphology, stage III-IV, and colorectal NEC disease. Patients with Ki-67 <55% and mixed/combined morphology had better survival than those with pure morphology. Morphology pure or mixed/combined became irrelevant in NEC survival when Ki-67 was ≥55%. The prognosis of metastatic patients who did not receive any treatment tended to be worse compared to that of the treated group. The prognostic impact of Rb1 immunolabeling appears to be limited when multiple risk factors are simultaneously assessed.

CONCLUSION

The most effective parameters to predict OS for NEC patients could be Ki-67, pure or mixed/combined morphology, stage, and site.

Targeting ALK in Neuroendocrine Tumors of the Lung

Background

Anaplastic lymphoma kinase (ALK) rearrangements are known oncogenic drivers in non-small cell lung cancer (NSCLC). Few case reports described the occurrence of such rearrangements in large cell neuroendocrine carcinomas (LCNECs) of the lung without information on clinical responses to ALK tyrosine kinase inhibitors (TKIs) in these cases. Currently, neuroendocrine tumors of the lungs are not screened for ALK rearrangements.

Methods

To illustrate the clinical impact of molecular characterization in LCNECs, we report the disease course in three patients with ALK-rearranged metastatic LCNEC from our clinical routine, as well as their treatment response to ALK TKIs (index cases). To gain insight into the prevalence of ALK rearrangements in neuroendocrine tumors of the lung, we analyzed a retrospective cohort of 436 tumor biopsies including LCNEC (n = 61), small cell lung cancer (SCLC) (n = 206), typical (n = 91) and atypical (n = 69) carcinoids, and mixed histology (n = 9) for the presence of ALK rearrangements using a sequential diagnostic algorithm. ALK immunohistochemistry (IHC) was evaluable in 362 cases; fluorescence in situ hybridization (FISH) was evaluable in 28 out of the 35 IHC-positive cases, followed by next-generation sequencing (NGS) that was available in 12 cases.

Results

Within the retrospective cohort, ALK IHC was positive in 35 out of 362 (9.7%) evaluable samples. FISH was positive in 3 out of the 28 (10.7%) evaluable cases: 2 with atypical carcinoids and 1 with LCNEC. Additionally, the 3 index cases showed positive ALK IHC, which was confirmed by NGS. Within the retrospective cohort, NGS confirmed the presence of an ALK genomic rearrangement in one FISH-positive atypical carcinoid where material was sufficient for sequencing. Two out of three patients with metastatic ALK-rearranged LCNEC received up-front treatment with the ALK TKI alectinib and showed rapid tumor response at all metastatic sites, including multiple brain metastases.

Conclusions

ALK rearrangements represent rare but targetable oncogenic driver alterations in LCNEC. Contrarily to NSCLC, the detection of ALK rearrangements in neuroendocrine tumors of the lung is challenging, since ALK IHC can lead to false-positive results and therefore needs confirmation by FISH or NGS. Up-front comprehensive molecular profiling with NGS should be performed in metastatic LCNEC in order not to miss actionable genomic alterations.

Different Characteristics and Survival between Surgically Resected Pure and Combined Pulmonary Large Cell Neuroendocrine Carcinoma

BACKGROUND

Large cell neuroendocrine carcinoma (LCNEC) is a rare high-grade neuroendocrine carcinoma of the lung. Little is known about the differences between the pure and combined LCNEC subtypes, and thus we conducted this study to provide more comprehensive insight into LCNEC.

METHODS

We reviewed 221 patients with pure LCNEC (P-LCNEC) and 120 patients with combined LCNEC (C-LCNEC) who underwent pulmonary surgery in our hospital to compare their clinical features, driven genes' status (EGFR/ALK/ROS1/KRAS/BRAF), and adjuvant chemotherapy regimens. Propensity score matching (PSM) was applied to reduce selection bias.

RESULTS

The P-LCNEC group included a higher proportion of males and smokers than the C-LCNEC group. Furthermore, the C-LCNEC group had higher incidences of visceral pleural invasion (VPI), EGFR mutation and ALK rearrangement compared with the P-LCNEC group. Expression of neuroendocrine markers (CD56, CGA, and SYN) and recurrence patterns were not significantly different between the two groups. The P-LCNEC group had better disease-free survival (DFS) and overall survival (OS) compared with the C-LCNEC group (median DFS: 67.0 vs. 28.1 months, p = 0.021; median OS: 72.0 vs. 45.0 months, p = 0.001), which was further confirmed by the PSM method (p = 0.004 and p < 0.001, respectively). Adjuvant chemotherapy was also an independent factor for DFS and OS. Subgroup analysis found that regardless of whether it was for the entire LCNEC group or the P- and C-LCNEC subtypes, the small cell lung cancer (SCLC) regimens presented with superior survival compared with the non-small cell lung cancer (NSCLC) regimens.

CONCLUSION

P-LCNEC was associated with more favorable prognosis compared with C-LCNEC. SCLC-based adjuvant chemotherapy was more appropriate for LCNEC patients than NSCLC-based regimens, regardless of whether they were the pure or combined LCNEC subtypes. C-LCNEC patients may be the potential beneficiary of targeted therapy.

Management of Large Cell Neuroendocrine Carcinoma

BACKGROUND

Large cell neuroendocrine carcinoma (LCNEC) is a rare, aggressive cancer with a dismal prognosis. The majority of cases occur in the lung and the gastrointestinal tract; however, it can occur throughout the body. Recently advances in the understanding of the molecular underpinnings of this disease have paved the way for additional novel promising therapies. This review will discuss the current best evidence for management of LCNEC and new directions in the classification and treatment of this rare disease.

METHODS

We performed a PubMed search for "Large cell neuroendocrine carcinoma" and "High grade neuroendocrine carcinoma." All titles were screened for relevance to the management of LCNEC. Papers were included based on relevance to the management of LCNEC.

RESULTS

Papers were included reviewing both pulmonary and extra pulmonary LCNEC. We summarized the data driven best practices for the management of both early and advanced stage LCNEC. We describe emerging therapies with promising potential.

DISCUSSION

LCNEC are rare and aggressive neoplasms. In advanced disease, the historical regimen of platinum based therapy in combination with etoposide or irinotecan remains among the commonly used first line therapies, however for extra thoracic LCNEC regimens like FOLFOX, FOLFOIRI and CAPTEM can also be used. Further effective and safe treatment options are desperately needed. Recently, new advances including a new understanding of the genetic subcategories of LCNEC and immunotherapy agents may guide further treatments.

Survival outcomes of surgery in patients with pulmonary large-cell neuroendocrine carcinoma: a retrospective single-institution analysis and literature review

Background

Pulmonary large-cell neuroendocrine carcinoma (pLCNEC) is a very rare malignancy originating from the lung and bronchus, and its biological behaviour, clinical diagnosis, treatment and prognosis are poorly understood. Thus, the clinical characteristics and surgical treatment-related prognostic factors of this rare disorder must be explored.

Results

The clinical data of 59 patients (48 males and 11 females) who were treated by surgery and diagnosed with pLCNEC by postoperative pathology at Peking Union Medical College Hospital from April 2004 to April 2019 were analysed retrospectively. The median patient age was 62 years (38–79 years), and the median duration of disease was 2 months (0.5–18 months). Compared with other lung malignancies, pLCNEC lacks specific clinical symptoms and imaging features, and preoperative biopsy pathology is often insufficient to confirm the diagnosis. The corresponding numbers of patients who were classified into stages I, II, III and IV according to the postoperative pathological tumour-nodal-metastasis stage were 25, 12, 15 and 7, respectively. The median overall survival was 36 months (0.9–61.1 months). The 1-year, 3-year and 5-year survival rates were 76.3%, 49% and 44.7%, respectively. The tumour stage exerted a significant effect on survival (Cox multivariate analysis p < 0.05).

Conclusions

For patients with resectable pLCNEC, multidisciplinary therapy based on surgery may have good survival benefits, and tumour stage is an independent risk factor for the prognosis of pLCNEC.

Ki-67 Index of 55% Distinguishes Two Groups of Bronchopulmonary Pure and Composite Large Cell Neuroendocrine Carcinomas with Distinct Prognosis

BACKGROUND

Little information is available concerning prognostic factors for bronchopulmonary large cell neuroendocrine carcinomas (BP-LCNECs) and even less is known about combined LCNECs (Co-LCNECs). We investigated whether an integrated morphological, immunohistochemical, and molecular approach could be used for their prognostic evaluation.

METHODS

Morphological (including combined features), proliferative (mitotic count/Ki-67 index), immunohistochemical (napsin A, p40, TTF-1, CD44, OTP, SSTR2A, SSTR5, mASH1, p53, RB1, and MDM2), and genomic (TP53, RB1, ATM, JAK2, KRAS, and STK11) findings were analyzed in BP-LCNECs from 5 Italian centers, and correlated with overall survival (OS). The Ki-67 index was expressed as the percentage of positive cells in hot spots as indicated in the WHO 2019 Digestive System Tumors and, for Co-LCNECs, the Ki-67 index was evaluated only in the LCNEC component.

RESULTS

A total of 111 LCNECs were distinguished into 70 pure LCNECs, 35 Co-LCNECs (27 with adenocarcinoma [ADC] and 8 with squamous cell carcinoma [SqCC]), and 6 LCNECs with only napsin A immunoreactivity. The Ki-67 index cutoff at 55% evaluated in the neuroendocrine component was the most powerful predictor of OS (log-rank p = 0.0001) in all LCNECs; 34 cases had a Ki-67 index <55% (LCNEC-A) and 77 had a Ki-67 index ≥55% (LCNEC-B). Statistically significant differences in OS (log-rank p = 0.0001) were also observed between pure and Co-LCNECs. A significant difference in OS was found between pure LCNECs-A and Co-LCNECs-A (p < 0.05) but not between pure LCNECs-B and Co-LCNECs-B. Co-LCNEC-ADC and LCNEC napsin A+ cases had longer OS than pure LCNEC and Co-LCNEC-SqCC cases (log-rank p = 0.0001). On multivariable analysis, tumor location, pure versus combined features, and napsin A, but no single gene mutation, were significantly associated with OS after adjustment for Ki-67 index and study center (p < 0.05).

CONCLUSIONS

The Ki-67 proliferation index and the morphological characterization of combined features in LCNECs seem to be important tools for predicting clinical outcome in BP-LCNECs.

Diagnostic Value of Insulinoma-Associated Protein 1 (INSM1) and Comparison With Established Neuroendocrine Markers in Pulmonary Cancers

CONTEXT.—

The diagnostic distinction of pulmonary neuroendocrine (NE) tumors from non-small cell lung carcinomas (NSCLCs) is clinically relevant for prognostication and treatment. Diagnosis is based on morphology and immunohistochemical staining.

OBJECTIVE.—

To determine the diagnostic value of insulinoma-associated protein 1 (INSM1), in comparison with established NE markers, in pulmonary tumors.

DESIGN.—

Fifty-four pulmonary NE tumors and 632 NSCLCs were stained for INSM1, CD56, chromogranin A, and synaptophysin. In a subset, gene expression data were available for analysis. Also, 419 metastases to the lungs were stained for INSM1. A literature search identified 39 additional studies with data on NE markers in lung cancers from the last 15 years. Seven of these included data on INSM1.

RESULTS.—

A positive INSM1 staining was seen in 39 of 54 NE tumors (72%) and 6 of 623 NSCLCs (1%). The corresponding numbers were 47 of 54 (87%) and 14 of 626 (2%) for CD56, 30 of 54 (56%) and 6 of 629 (1%) for chromogranin A, and 46 of 54 (85%) and 49 of 630 (8%) for synaptophysin, respectively. Analysis of literature data revealed that CD56 and INSM1 were the best markers for identification of high-grade NE pulmonary tumors when considering both sensitivity and specificity, while synaptophysin also showed good sensitivity. INSM1 gene expression was clearly associated with NE histology.

CONCLUSIONS.—

The solid data of both our and previous studies confirm the diagnostic value of INSM1 as a NE marker in pulmonary pathology. The combination of CD56 with INSM1 and/or synaptophysin should be the first-hand choice to confirm pulmonary high-grade NE tumors. INSM1 gene expression could be used to predict NE tumor histology.

Exploring imaging features of molecular subtypes of large cell neuroendocrine carcinoma (LCNEC)

OBJECTIVES

Radiological characteristics and radiomics signatures can aid in differentiation between small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC). We investigated whether molecular subtypes of large cell neuroendocrine carcinoma (LCNEC), i.e. SCLC-like (with pRb loss) vs. NSCLC-like (with pRb expression), can be distinguished by imaging based on (1) imaging interpretation, (2) semantic features, and/or (3) a radiomics signature, designed to differentiate between SCLC and NSCLC.

MATERIALS AND METHODS

Pulmonary oncologists and chest radiologists assessed chest CT-scans of 44 LCNEC patients for 'small cell-like' or 'non-small cell-like' appearance. The radiologists also scored semantic features of 50 LCNEC scans. Finally, a radiomics signature was trained on a dataset containing 48 SCLC and 76 NSCLC scans and validated on an external set of 58 SCLC and 40 NSCLC scans. This signature was applied on scans of 28 SCLC-like and 8 NSCLC-like LCNEC patients.

RESULTS

Pulmonary oncologists and radiologists were unable to differentiate between molecular subtypes of LCNEC and no significant differences in semantic features were found. The area under the receiver operating characteristics curve of the radiomics signature in the validation set (SCLC vs. NSCLC) was 0.84 (95% confidence interval (CI) 0.77-0.92) and 0.58 (95% CI 0.29-0.86) in the LCNEC dataset (SCLC-like vs. NSCLC-like).

CONCLUSION

LCNEC appears to have radiological characteristics of both SCLC and NSCLC, irrespective of pRb loss, compatible with the SCLC-like subtype. Imaging interpretation, semantic features and our radiomics signature designed to differentiate between SCLC and NSCLC were unable to separate molecular LCNEC subtypes, which underscores that LCNEC is a unique disease.

Are neuroendocrine negative small cell lung cancer and large cell neuroendocrine carcinoma with WT RB1 two faces of the same entity?

Until recently, small cell lung cancer (SCLC) was described as SCLC and SCLC variant, based upon cellular morphology and loss of neuroendocrine markers in the SCLC variant. However, based on recent research advances, driven in part by the increase in comprehensive genomic data, it has become clear that there are multiple SCLC subtypes including an ASCL1 and NEUROD1 low, YAP1 high (SCLC-Y) subtype enriched for WT RB1. Comparing morphological and other features of this SCLC subtype to neuroendocrine negative RB1, KEAP1, STK11 WT LCNEC raises a number of important questions with diagnostic and therapeutic implications.

Basket Trials for Intractable Cancer

Currently, genomic characterization has become standard of care for tumor types such as non-small cell lung cancer, breast cancer, melanoma, and colorectal cancer. A deep understanding of genomic alterations in different tumor types would help identify potentially actionable genomic changes which occur across a wide variety of tumor types. A basket trial is a new type of clinical trial for which eligibility is based on the presence of a specific genomic alteration, irrespective of histology. Basket trials are phase II screening trials for the off-label use of a targeted drug in patients with the same genomic alterations for which it was approved. Intractable cancer refers to a type or condition of cancer which is unresponsive or resistant to treatment; intractable cancers may be classified into five subtypes as follows: hard-to-treat condition of common advanced cancer after multiple-line therapy, rare cancer in which no standard of care has been recommended, advanced cancer in which standard of care does not work well, cancer accompanied with organ dysfunction, and cancers in older or younger cancer patients. Previous studies have demonstrated that in basket trials, genomic-guided therapy yields clinical benefits in intractable cancer, thereby providing novel insights into the optimal clinical management of such cancers. In this review, we describe a novel way to classify intractable cancer, and summarize the current knowledge on such cancers. We additionally provide information on the role of basket trials in intractable cancer.

Clinicopathological characteristics, treatment and survival of pulmonary large cell neuroendocrine carcinoma: a SEER population-based study

Background

This study was designed to investigate the clinicopathological characteristics, treatment and survival of patients with pulmonary large cell neuroendocrine carcinoma (LCNEC).

Methods

The Surveillance, Epidemiology and End Results database was utilized to identify patients diagnosed with pulmonary LCNEC between 2004 and 2013. Kaplan–Meier analysis was conducted to determine the overall survival (OS) and cancer-specific survival (CSS) rate. Univariate survival analysis along with log-rank test, and Cox proportional hazards model were employed to detect independent prognostic factors.

Results

Pulmonary LCNEC accounted for 0.58% (2972/510607) of the total number of lung and bronchus carcinoma. And a total of 1,530 eligible cases were identified, with the median follow-up time of 11 months. To be specific, the 3-, 5-year OS and CSS rates were 22.8%, 16.8% and 26.5%, 20.8% respectively. Generally, pulmonary LCNEC was commonly detected in the elderly (72.2%), males (55.9%), the upper lobe (62.0%) and advanced AJCC stage (65.5%). Multivariate analysis revealed that elderly [(≥60 and <80 years) HR:1.203, 95% CI [1.053–1.375], P = 0.007; (≥80 years) HR:1.530, 95% CI [1.238–1.891], P < 0.001] and advanced AJCC stage [(stage III) HR:2.606, 95% CI [2.083–3.260], P < 0.001; (stage IV) HR:4.881, 95% CI [3.923–6.072], P < 0.001] were independent unfavorable prognostic factors, and that female (HR:0.845, 95% CI [0.754–0.947], P = 0.004)), surgery [(Segmentectomy/wedge resection) HR:0.526, 95% CI [0.413–0.669], P < 0.001; (Lobectomy/Bilobectomy) HR:0.357, 95% CI [0.290–0.440], P < 0.001;(Pneumonectomy) HR:0.491, 95% CI [0.355–0.679], P < 0.001] , chemotherapy (HR:0.442, 95% CI [0.389–0.503], P < 0.001) and radiation (HR:0.837, 95% CI [0.738–0.949], P = 0.005) were independent favorable prognostic factors.

Conclusion

To sum up, age at diagnosis, sex, AJCC 8th edition stage, surgery, chemotherapy and radiation were significantly associated with OS of patients with pulmonary LCNEC.

Larger tumors are associated with inferior progression-free survival of first-line EGFR-tyrosine kinase inhibitors and a lower abundance of EGFR mutation in patients with advanced non-small cell lung cancer

BACKGROUND

The impact of primary tumor size on the therapeutic outcomes of EGFR-tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) with EGFR mutation remains unclear.

METHODS

A total of 291 consecutive patients with advanced EGFR-mutant NSCLC administered first-line EGFR-TKIs were enrolled. Computed tomography was used to assess primary tumor diameter. The amplification refractory mutation system plus was used to quantitatively evaluate the abundance of EGFR mutations. Associations between depth of response, abundance of EGFR mutations, and tumor size was investigated.

RESULTS

Patients were divided into three groups according to T classification: ≤ 3 cm (n = 109), 3-5 cm (n = 121), and > 5 cm (n = 61). Median progression-free survival (PFS) was significantly longer in the ≤ 3 cm and 3-5 cm groups compared to the > 5 cm group (10.8 vs. 10.5 vs. 7.1 months; P < 0.001). Subgroup analysis revealed a consistent result in patients with exon 19 deletion and 21 L858R mutation. Multivariate analysis revealed that tumor size was an independent predictive factor for PFS (hazard ratio 1.528, 95% confidence interval 1.104-2.115; P = 0.010). Larger tumors (> 5 cm) were marginally significantly less EGFR-mutant abundant than smaller tumors (≤ 5 cm) (mean ± standard deviation 30.5 ± 29.5% vs. 45.8 ± 43.1%; P = 0.08).

CONCLUSION

Larger tumors (> 5 cm) were associated with inferior PFS of first-line EGFR-TKI therapy in advanced NSCLC patients with activating EGFR mutations. A potential explaination might be that EGFR mutations are less abundant in larger tumors.

Thick-wall cavity predicts worse progression-free survival in lung adenocarcinoma treated with first-line EGFR-TKIs

BACKGROUND

Cavity occurs in 5.7 to 14.9% of patients with lung adenocarcinoma (ADC). However, the impact of cavity on the therapeutic response to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in ADC patients with EGFR mutations remains unclear. The aim of the present retrospective study was to elucidate the incidence and detailed characteristics of EGFR-mutant cavitary ADC and investigate the efficacy of EGFR-TKI treatment in this subgroup.

METHODS

Two hundred seventy-six consecutive patients with advanced EGFR-mutant lung ADC treated with first-line EGFR-TKIs were enrolled. Cavitation and the thickness of cavity wall were assessed based on high-resolution computed tomography scans. Progression-free survival (PFS) was analyzed by the Kaplan-Meier plots and the log-rank test was used to calculate the significance between groups.

RESULTS

Cavity occurred in 5.4% (15/276) of patients with EGFR-mutant lung ADC and was more prevalent among male patients (66.7% vs. 33.3%, P = 0.008). Of the 15 EGFR-mutant cavitary ADC, 9 patients had exon 19 deletion (19DEL) and 6 harbored L858R mutation, 9 patients had thick-wall cavity while 6 had thin-wall cavity. Cavity had an adverse impact on the PFS of EGFR-mutant ADC treated with first-line EGFR-TKIs (noncavity versus cavity, 11.0 versus 6.5 months, hazard ratio [HR]: 0.33, 95% confidence interval [CI], 0.15-0.73, P = 0.003). The impaired effect was only observed in patients with L858R mutation (11.0 vs. 4.2 months, HR: 0.05, 95%CI, 0.01-0.27, P = 0.0003) but not in those with 19DEL (10.4 versus 9.7 months, HR: 0.73, 95%CI, 0.30-1.75, P = 0.483). All six L858R-mutant cavitary ADC patients had thick-wall cavity while thick-wall cavity was only identified in one thirds (3/9) of patients with 19DEL. Further analyses showed that patients with thick-wall cavity had worse PFS (6.0 versus 11.0 months, P = 0.013). Multivariate analysis identified cavity as an independent predictive factor for PFS (HR: 0.49, 95% CI, 0.26-0.90, P = 0.022).

CONCLUSION

Cavitary ADC was associated with a worse PFS of first-line EGFR-TKI therapy, mainly in those with L858R mutation. Thick-wall cavity formation may be the main cause that contribute to the worse PFS.