Lung adenocarcinoma with sarcomatoid transformation after tyrosine kinase inhibitor treatment and chemotherapy

Histological sarcomatoid transformation in a lung adenocarcinoma patient following immune checkpoint blockade

Histological transformation is a phenomenon that is well described as one of the causes of tyrosine kinase inhibitor resistance in oncogene-driven non-small-cell lung cancer (NSCLC). The use of immune checkpoint inhibitors (ICIs) as a potential mechanism of acquired resistance to immunotherapy in NSCLC to small-cell lung cancer was also recently found. Here, we report the histological transformation of sarcomatoid carcinoma and metastasis in a lung adenocarcinoma patient without targetable genetic alterations who experienced long-term disease remission after nivolumab therapy. The patient subsequently developed rapid progression in the mediastinal and retroperitoneal lymph nodes, bones, and small intestine. Surgical resection of the small intestine lesion due to acute small intestine bleeding revealed the transformation of NSCLC to sarcomatoid carcinoma. The patient died 3 months after sarcomatoid carcinoma transformation and extensive disease progression, although he was rechallenged with immunotherapy. Genomic and immunohistochemical analyses revealed a comparable abundance of gene mutations and a limited number of immune cells in the tumor microenvironment, with low infiltration of CD8+ T cells, CD4+ T cells, regulatory T cells, and PD-L1+ macrophages in metastatic tumors, revealing a noninflamed immune microenvironment for ICI-resistant tumors.

Salvage Surgery for Advanced Lung Adenocarcinoma After Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Treatment

BACKGROUND

No published studies to date have evaluated the detailed pathologic and genetic features of lung adenocarcinoma after epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy and salvage surgery. We aimed to evaluate the pathologic and genetic changes of tumors in patients with advanced lung adenocarcinoma treated with EGFR TKI therapy and salvage surgery.

METHODS

This study retrospectively collected data from 29 advanced lung adenocarcinoma patients who underwent EGFR TKI therapy, followed by salvage operation, between January 2010 and December 2018. All patients had partial response or stable disease without evidence of progressive disease. Next-generation sequencing was used to determine whether acquired resistant mutations in morphologically treatment-sensitive and morphologically treatment-resistant regions of tumor existed.

RESULTS

There were 3, 22, and 4 patients with clinical stage IIIB, IVA, and IVB, respectively. After a mean TKI treatment duration of 134 days, 27 patients had partial response, 2 had stable disease, and 27.6% of patients were downstaged before salvage surgery. All patients had residual viable tumor cells in their tumor bed; 5 patients (17.2%) had a major pathologic response. Acquired T790M mutations (n = 4), histologic transformations (n = 2), and acquired T790M mutation with histologic transformation (n = 1) were identified in the morphologically treatment-resistant regions of tumors. The 3-year overall survival was 75.9%.

CONCLUSIONS

The presence of morphologically treatment-resistant tumor regions with acquired T790M mutations and histologic transformations demonstrate the existence of resistant subclones in TKI-treated tumors before disease progression. Salvage surgery performed in selected patients before disease progression may improve survival by removing TKI-resistant subclones.

Clinicopathological features and prognostic nomogram of giant cell carcinoma of the lung: A population-based study

BACKGROUND

Due to its rarity, the features and prognosis of giant cell carcinoma of the lung (GCCL) are not well defined. The present study aimed to describe the clinicopathological features and prognostic analysis of this rare disease, compare it with lung adenocarcinoma (LAC), further determine the prognostic factors and establish a nomogram.

METHODS

Patients diagnosed with GCCL and LAC were identified from the SEER database between 2004 and 2016. The features and survival between GCCL and LAC were compared in the unmatched and matched cohorts after propensity score matching (PSM) analysis. Univariate and multivariate Cox analyses were used to identify the prognostic factors, and a nomogram was constructed. Area under the curve (AUC), C-index, calibration curve and decision curve analysis (DCA) were used to confirm the established nomogram.

RESULTS

A total of 295 patient diagnosed with GCCL and 149 082 patients with LAC were identified. Compared with LAC, patients with GCCL tend to be younger, male, black and have pathological Grade III/IV GCCL, more proportion of AJCC-TNM-IV, T3/T4 and distant metastases. The 1-, 2- and 5-year OS rates of the patients with GCCL were 21.7%, 13.4% and 7.9%, respectively. The median OS and CSS were 3 and 4 months, respectively. Patients with GCCL had significantly shorter OS and CSS than those with LAC in the unmatched and matched cohorts after PSM. Multivariate Cox analysis demonstrated that T, N and M stages and use of chemotherapy and surgery were independent of survival. Furthermore, we constructed a prognostic nomogram for OS and CSS by using independent prognostic factors. The C-index of OS-specific nomogram is 0.78 (0.74-0.81), and the C-index of CSS-specific nomogram is 0.77 (0.73-0.80). The calibration curve and ROC analysis showed good predictive capability of these nomograms. DCA showed that the nomogram had greater clinical practical value in predicting the OS and CSS of GCCL than TNM staging.

CONCLUSION

GCCL have distinct clinicopathological characteristics and significantly worse clinical outcomes. Prognostic nomograms for overall survival (OS) and CSS were constructed.

Immune checkpoint inhibitors plus chemotherapy in patients with locally advanced or metastatic pulmonary sarcomatoid carcinoma: a multicentric real-world study

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have demonstrated promising efficacy as monotherapy in patients with pulmonary sarcomatoid carcinoma (PSC). We performed the current multi-institutional, real-world study to assess the efficacy of ICIs plus chemotherapy in patients with PSC.

METHODS

All consecutive patients with locally advanced or metastatic PSC from three centers treated with ICIs between January 2018 and July 2021 were enrolled. Programmed death ligand 1 (PD-L1) expression was stained and evaluated using immunohistochemical with 22C3. Single-cell RNA sequencing (scRNA-seq) was performed in two patients with PSC and two patients with adenocarcinoma to understand the cell-type-specific transcriptome landscape of cancer cells and tumor microenvironment (TME) of PSC.

RESULTS

A cohort of 42 PSC patients was identified. In the overall population, the objective response rate (ORR) was 73.8%, median progression-free survival (mPFS) was 10.3 months and median overall survival was not reached and 2-year survival rate was 51.2%. For 34 treatment-naïve patients who received first-line ICIs plus chemotherapy, the ORR was 70.6%, mPFS was 10.3 months and 2-year survival rate was 57.8%. In patients with PD-L1 tumor proportion score (TPS) < 1%, 1-49%, and ⩾50%, the ORR was 33.3%, 72.7%, and 85.7% and mPFS was 6.0, 6.7, and 10.3 months, respectively. Notably, two patients with transformed PSC from lung adenocarcinoma after epidermal growth factor receptor-tyrosine kinase inhibitor treatment also responded well to ICIs plus chemotherapy. scRNA-seq revealed immune-cell-inflamed TME, lower intratumoral heterogeneity, and activated immune response pathway in PSC.

CONCLUSIONS

Our study demonstrated remarkable efficacy of ICIs plus chemotherapy as first-line therapy for patient with locally advanced or metastatic PSC.

Immunophenotyping of pulmonary sarcomatoid carcinoma

Background

Previous studies have suggested that patients with pulmonary sarcomatoid carcinoma (PSC)may benefit from immune checkpoint inhibitors (ICIs); however, relevant data are lacking. This study aimed to establish the immunophenotype of PSC by assessing PD-L1 and CD8+ T-cell infiltration.

Methods

A retrospective analysis of pathologically confirmed PSC cases from two centers was performed from January 2009 to May 2021. According to the infiltration of CD8+ T cells in different spatial regions, patients were classified into three types: immune-inflamed, immune-excluded, and immune desert. PD-L1 staining was also performed on the intratumoral region and the tumor proportion score (TPS) was used for scoring. Combined with CD8+ T-cell infiltration and PD-L1 expression in the intratumoral region, immunophenotyping can be divided into four types: type I (PD-L1+/CD8+, adaptive immune resistance), type II (PD-L1-/CD8-, immunologic ignorance), type III (PD-L1+/CD8-, intrinsic induction), and type IV (PD-L1-/CD8+, tolerance). Finally, correlation analysis was performed on the immunophenotype, clinicopathological characteristics, and outcomes of the patients.

Results

A total of 32 patients with PSC were included in the final analysis. Of these patients, 65.6% (21/32), 15.6% (5/32), and 18.8% (6/32) were classified as immune-inflamed, immune-excluded, and immune-desert, respectively. Notably, the immune-inflamed type is predominantly observed in pleomorphic carcinomas (PC, 66.7%). Moreover, among these participants, 19 (59.4%) were classified as PD-L1 positive according to the TPS score. In particular, 11 (34.4%) patients had PD-L1 TPS scores >50%. Next, we immunophenotyped patients with PSC based on CD8+ T cell infiltration and tumor cell PD-L1 expression (types I–IV). Type I (PD-L1+/CD8+, adaptive immune resistance) was the most prevalent subtype, accounting for 46.9% (15/32), followed by type II (PD-L1-/CD8-, immunological ignorance) (21.9%), type IV (PD-L1-/CD8+, tolerance) (18.7%), and type III (PD-L1+/CD8-, intrinsic induction) (12.5%). Finally, we performed a survival analysis and found that neither immunophenotype was a predictor of prognosis in patients with PSC. Multivariate analysis showed that pneumonectomy increased the risk of death by four times compared with lobectomy (RR: 4.1; 95% CI:1.3-12.4, P=0.014).

Conclusion

Patients with PSC are characterized by immune-inflamed type and type I (PD-L1+/CD8+, adaptive immune resistance), explaining the intrinsic reasons for their high response rate to immunotherapy.

Histologic transformation in lung cancer: when one door shuts, another opens

Histologic transformation (HT) is a major cause of drug resistance to therapy in patients with lung cancer. HTs to small-cell lung cancer (SCLC) have been reported frequently in patients with epidermal growth factor receptor (EGFR)-mutated lung cancer. Although HTs have an impact on the clinical outcomes in patients owing to a high refractoriness to treatments, there is limited data on the prevalence, causes, mechanisms, treatment efficacy, and future treatment strategies. In this review, we assess the literature regarding HTs comprehensively, including those describing EGFR-tyrosine kinase inhibitors, other molecular targeted drugs, and immune checkpoint inhibitors. Furthermore, we discuss the mechanisms of HTs and the lineage plasticity to SCLC and squamous cell carcinoma in lung cancer. In addition, we summarize the treatment efficacy and future perspectives of HTs in patients with lung cancer, and propose better management strategies for this group of patients.

Pulmonary Carcinosarcoma: A Rare Disease With Challenging Diagnosis and Treatment

Pulmonary carcinosarcoma (PCS) is a rare type of non-small cell cancer. Overall, middle-aged and older smokers are the most affected age and sex groups. The diagnosis of PCS is difficult due to the absence of characteristic imaging findings. Additionally, preoperative biopsies do not usually reflect the heterologous nature of this tumor. Given the rarity of such tumors and the challenging diagnosis, the prognostic factors have not been established, and the overall prognosis remains poor. The valid therapeutic options are still limited. Here, we report a rare case of metastatic PCS that was accidentally discovered by imaging and properly diagnosed after surgical resection. The clinicopathological features, diagnostic tools, genetic theories, prognosis, and therapeutic options of this rare cancer are also discussed.

Histological Transformation after Acquired Resistance to the Third-Generation EGFR-TKI in Patients with Advanced EGFR-Mutant Lung Adenocarcinoma

Background and Objectives: Third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) is one of the standard-of-care therapies in patients with EGFR-mutant lung adenocarcinoma; however, acquired resistance inevitably developed. Despite the proposition of histological transformation being one of the resistance mechanisms, its incidence and influence on outcome remain unclear. Materials and Methods: This was a retrospective study conducted at Taichung Veterans General Hospital on patients with advanced EGFR-mutant lung adenocarcinoma receiving the third-generation EGFR-TKI. Only patients receiving rebiopsy were included in the analysis. Results: A total of 55 patients were studied. Eight patients (14.5%) showed histological transformation, including three small cell carcinoma, three squamous cell carcinoma, one large cell neuroendocrine carcinoma, and one with a mixture of adenocarcinoma and squamous cell carcinoma components. The median treatment duration of the third-generation EGFR-TKI before rebiopsy was numerically longer in patients with histological transformation than those without (16.0 vs. 10.9 months). Both the overall survival time from the start of third-generation EGFR-TKI initiation (30.8 vs. 41.2 months) and from rebiopsy (6.6 vs. 12.9 months) to mortality were numerically shorter amongst the transformed population. All patients in the transformed group did not respond to the next line of systemic treatment. One patient with histological transformation receiving local treatment for the metastatic site had a longer overall survival. Conclusions: Repeating biopsy to identify histological transformation should be considered in patients with progression to the third-generation EGFR-TKI. Histological transformations could contribute to the acquired resistance with the implication of a worse prognosis. Further studies are needed to determine the optimal therapy for these patients.

A Rare Case of Neck Sarcomatoid Squamous Cell Carcinoma With Brain Metastases

Squamous cell carcinoma (SCC) is the second most prominent form of skin malignancy. It occurs most frequently in older males with fair skin complexion that have extensive sun exposure most commonly in their childhood. The metastatic presentation of SCC is rare and is most common in the lung. In this paper, we present the unique case of a 73-year-old patient with sarcomatoid squamous cell carcinoma in their posterior neck that metastasized to the brain.

ESMO expert consensus statements on the management of EGFR mutant non-small-cell lung cancer

The European Society for Medical Oncology (ESMO) held a virtual consensus-building process on epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer in 2021. The consensus included a multidisciplinary panel of 34 leading experts in the management of lung cancer. The aim of the consensus was to develop recommendations on topics that are not covered in detail in the current ESMO Clinical Practice Guideline and where the available evidence is either limited or conflicting. The main topics identified for discussion were: (i) tissue and biomarkers analyses; (ii) early and locally advanced disease; (iii) metastatic disease and (iv) clinical trial design, patient's perspective and miscellaneous. The expert panel was divided into four working groups to address questions relating to one of the four topics outlined above. Relevant scientific literature was reviewed in advance. Recommendations were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This manuscript presents the recommendations developed, including findings from the expert panel discussions, consensus recommendations and a summary of evidence supporting each recommendation.

Morphologic-Molecular Transformation of Oncogene Addicted Non-Small Cell Lung Cancer

Patients with non-small cell lung cancer, especially adenocarcinomas, harbour at least one oncogenic driver mutation that can potentially be a target for therapy. Treatments of these oncogene-addicted tumours, such as the use of tyrosine kinase inhibitors (TKIs) of mutated epidermal growth factor receptor, have dramatically improved the outcome of patients. However, some patients may acquire resistance to treatment early on after starting a targeted therapy. Transformations to other histotypes—small cell lung carcinoma, large cell neuroendocrine carcinoma, squamous cell carcinoma, and sarcomatoid carcinoma—have been increasingly recognised as important mechanisms of resistance and are increasingly becoming a topic of interest for all specialists involved in the diagnosis, management, and care of these patients. This article, after examining the most used TKI agents and their main biological activities, discusses histological and molecular transformations with an up-to-date review of all previous cases published in the field. Liquid biopsy and future research directions are also briefly discussed to offer the reader a complete and up-to-date overview of the topic.

CtBP1 Mediates Hypoxia-Induced Sarcomatoid Transformation in Hepatocellular Carcinoma

Background

Sarcomatoid hepatocellular carcinoma (sHCC), a highly aggressive subtype of hepatocellular carcinoma (HCC), mostly transforms from classical hepatocellular carcinoma (cHCC). The study intended to explore the role of C-terminal binding protein 1 (CtBP1) in sarcomatoid transformation of hepatocellular carcinoma.

Methods

Western blotting and/or immunohistochemistry were used to confirm the expression of CtBP1 and other proteins in HCC cells, xenografts and clinical tissue samples. CtBP1 shRNA-expressing lentivirus was used to infect HepG2 cells to construct CtBP1 knockdown cells. Cell migration was determined by scratch wound assays and Transwell assays. Immunofluorescence was used to label the a-tubulin cytoskeleton to evaluate cell morphology. HepG2 cells were inoculated subcutaneously in nude mice to construct xenografts and beneath the liver capsule to evaluate in vivo metastasis.

Results

Compared to that in the cHCC area, CtBP1 expression was significantly upregulated in the sHCC area, as shown by immunohistochemistry. HE staining showed that cells in the sHCC area were spindle-shaped, while those in the cHCC area were polygonal. Immunohistochemically, the epithelial markers pancytokeratin (CK) and E-cadherin were partially or completely lost, while the expression of the mesenchymal marker vimentin was upregulated in the sHCC area. Moreover, HepG2, an HCC cell line with high expression of CtBP1, autonomously underwent sarcomatoid transformation, showing a sarcomatoid morphology and phenotype. HIF1a expression was upregulated in epithelial cells adjacent to the sHCC area. Hypoxia upregulated CtBP1 protein expression and induced an EMT phenotype with increased migration and a spindle-shaped morphology in HepG2 cells. Knockdown of CtBP1 partially reversed the EMT phenotype induced by hypoxia. Silencing CtBP1 completely blocked the sarcomatoid transformation of subcutaneous xenografts and decreased lung metastasis in subcapsular xenografts of the liver in nude mice.

Conclusion

CtBP1 plays a key role in hypoxia-induced EMT and sarcomatoid transformation in HCC and could be a candidate target for the management of sHCC.

Histologic Transformation in EGFR-Mutant Lung Adenocarcinomas: Mechanisms and Therapeutic Implications

With the advent of potent EGFR tyrosine kinase inhibitors (TKIs), the treatment landscape of EGFR-mutant lung adenocarcinomas has changed drastically in recent years. However, the development of resistance to EGFR TKIs remains a critical barrier to improving survival in these patients. Histologic transformations to small cell lung carcinoma, large cell neuroendocrine carcinoma, squamous cell carcinoma, and the sarcomatoid phenotype have been increasingly recognized as important mechanisms of resistance. In this article, we summarize the known biological bases for such phenotypic switches in regard to EGFR TKIs and describe novel pathways that might be harnessed to develop effective novel therapies for patients with EGFR-mutant non-small cell lung cancers.

Report of Two Pulmonary Sarcomatoïd Carcinoma Cases With Highlights on the Computed Tomography Features

Pulmonary sarcomatoïd carcinomas are a heterogeneous group of poorly differentiated non-small cell tumors with a sarcomatous component. On imaging, they appear as peripheral or central masses, sometimes excavated. We report two cases of pulmonary sarcomatoïd lung carcinoma. The first case involves a 73-year-old active smoker who presented with dyspnea. A computed tomography (CT) scan showed a large locally advanced left lower lobar tumor process. A CT-guided biopsy was performed and the histopathological examination concluded a pulmonary sarcomatoïd carcinoma. The second case involves a 52-year-old chronic smoker who presented with hemoptysis. CT pulmonary angiography showed an excavated right upper lobar tumor. Histologic work-up of the right upper lobectomy piece objectified a pulmonary sarcomatoïd carcinoma. Pulmonary sarcomatoïd carcinoma has a nonspecific appearance on imaging and should be a part of imaging differential diagnoses in front of a large, lobulated, highly invasive lung tumor with or without excavation.

Transformation of Two Cases of Lung Adenocarcinoma into Pulmonary Sarcomatoid Carcinoma following Treatment

Accumulating evidence shows that histologic transformation is involved in the drug resistance of lung cancer. Moreover, it is common for lung adenocarcinoma to transform into small-cell lung cancer or squamous cell carcinoma; however, clinical cases with sarcomatoid transformation have been rarely reported. Thus, both the diagnosis and treatment of lung adenocarcinoma with sarcomatoid transformation remain difficult. Here, we discuss two patients with lung adenocarcinoma with sarcomatoid transformation—analyzing the diagnosis, clinical features, immunohistochemical characteristics, therapy, and prognosis—with the hope that this report will be used as a reference for future treatment of these patients.

Pulmonary sarcomatoid carcinoma: progress, treatment and expectations

Pulmonary sarcomatoid carcinoma (PSC) is a unique, highly invasive pulmonary malignancy with a poor prognosis, representing 0.1-0.4% of all malignant lung tumors. Because of its highly aggressive character and propensity for frequent metastasis, PSC shows low response rates to traditional treatments such as chemotherapy, radiotherapy, and neoadjuvant therapy. In recent years, considerable progress has been made in gene sequencing, targeted therapies, and immunotherapies. One of the most promising treatment approaches is the selection of mono-targeted or multi-targeted drugs according to tumor gene-mutation sites, such as epidermal growth factor receptor or vascular endothelial growth factor receptor 2 (EGFR/VEGFR2), anaplastic lymphoma kinase (ALK), and others. Another approach is the activation of therapeutic anti-tumor immunity via pathways including programmed cell-death protein-1/programmed cell-death ligand-1 (PD-1/PD-L1), which has been used in individual cases. In this review, we will introduce the clinicopathologic features, molecular typing, and traditional treatments. We will also review the biological characteristics and the latest therapies for PSC. These novel therapies show promise in the management of PSC, and the outcomes of investigative trials will hopefully reveal a variety of treatment options for patients with PSC.

Approaches to Tumor Classification in Pulmonary Sarcomatoid Carcinoma

Pulmonary sarcomatoid carcinoma (PSC) is a heterogeneous category of primary lung cancer accounting from 0.3% to 3% of all primary lung malignancies. According to the most recent 2015 World Health Organization (WHO) classification, PSC includes several different variants of malignant epithelial tumors (carcinomas) histologically mimicking sarcomas showing or entirely lacking a conventional component of non-small cell lung cancer (NSCLC). Thus, this rare subheading of lung neoplasms includes pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, pulmonary blastoma, and carcinosarcoma. A diagnosis of PSC may be suspected on small biopsy or cytology, but commonly requires a surgical resection to reach a conclusive definition. The majority of patients with PSC consists of elderly, smoking men with a large, peripheral mass characterized by well-defined margins. However, presentation with a central, polypoid endobronchial lesion is well-documented, particularly in pleomorphic carcinoma and carcinosarcoma showing a squamous cell carcinoma component. As expected, PSC may pose diagnostic problems and immunohistochemistry is largely used when pathologists deal these tumors in routine practice. Indeed, PSC tends to overexpress molecules associated with the epithelial-to-mesenchymal transition, such as vimentin, but the panel of immunostains also includes epithelial markers (cytokeratins, EMA), TTF-1, p40 and negative markers (e.g., melanocytic, mesothelial and sarcoma-related primary antibodies). Although rare, PSC has increased their interest among oncologist community for different reasons: a. identification of the epithelial-to-mesenchymal phenomenon as a major mechanism of secondary resistance to tyrosine kinase inhibitors; b. over-expression of PD-L1 and effective treatment with immunotherapy; c. identification of c-MET exon 14 skipping mutation representing an effective target to crizotinib and other specific inhibitors. In this review, the feasibility of the diagnosis of PSC, its differential diagnosis and novel molecular findings characterizing this group of lung tumor are discussed.