Combined small-cell lung carcinoma: An institutional experience

A combined small cell lung carcinoma patient with only small cell carcinoma components in mediastinal lymph node metastasis and chondrosarcoma-like components in liver metastasis

A 69-year-old ex-smoker Japanese man presented with a left mediastinal lymph node and left upper lobe tumour. Bronchoscopic biopsy specimens from the enlarged left mediastinal lymph node and left upper lobe tumour revealed small cell lung carcinoma (SCLC). He was treated with first-line chemotherapy with carboplatin, etoposide, and atezolizumab for four courses and subsequent atezolizumab maintenance therapy. However, his left upper lobe lung tumour only increased in size, and left upper lobectomy revealed combined SCLC (adenocarcinoma and chondrosarcoma-like features). Four months after lobectomy, liver metastasis of chondrosarcoma-like features (similar to pathological findings of the left upper lobe tumour) were observed. Combined SCLC, including sarcomatous components, is rare and poorly responds to chemotherapy. The metastases of combined SCLC in this patient were of only one type of histological component, making diagnosis and treatment difficult. If treatment for SCLC responds inadequately, considering combined SCLC and actively re-examining histological diagnosis is necessary.

Combined small cell lung cancer: current progress and unmet needs

Combined small cell lung cancer (CSCLC) is a specific subtype of lung cancer characterized by a pathological mixture of small cell lung cancer and any subtype of non-small cell lung cancer components. Currently, our understanding of the clinicopathological features, origin, molecular characterization, treatment, and prognosis of CSCLC remains limited. CSCLCs represent examples of intratumor heterogeneity and pose challenges for accurate diagnosis. Are there any distinct clinicopathologic and molecular differences between pure SCLC and CSCLC? Furthermore, the prognostic outcomes and optimal treatments for CSCLC are urgently needed. This article aims to summarize the current biological features and clinical management of CSCLC, providing a reference for further understanding of this heterogeneous form of small cell lung cancer.

Clinicopathological and Treatment Patterns of Combined Small-Cell Lung Carcinoma with Future Insight to Treatment: A Population-Based Study

BACKGROUND

Primary lung cancer is the most common cause of cancer-related mortality in the United States (US). Approximately 90% of lung cancers are associated with smoking and the use of other tobacco products. Based on histology, lung cancers are divided into small-cell lung carcinomas (SCLCs) and non-small-cell lung carcinomas (NSCLCs). Most SCLCs are of the pure subtype, while the rare combined SCLCs contain elements of both small-cell and non-small-cell morphologies. This study sought to evaluate the demographics, clinical factors, molecular abnormalities, treatment approaches, and survival outcomes with combined SCLC and NSCLCs.

MATERIALS AND METHODS

Data on 2126 combined SCLC patients was extracted from the Surveillance Epidemiology and End Result (SEER) database from 2000 to 2018. Data extracted for analyses included age, sex, race, tumor size, tumor location, metastasis status, stage at diagnosis, treatment received, and treatment outcomes. Multivariate analysis was performed using Statistical Product and Service Solutions (SPSS) software.

RESULTS

The patients had a median age of 68 years; 43.9% of the patients were female and 56.1% were male; 84.5% were White and 11.7% were African Americans. The majority of patients had a poorly differentiated disease at 29.6%; 17% were undifferentiated, 3.2% were moderately differentiated, and 0.8% were well differentiated. Chemotherapy was the most common treatment modality (45.3%); 17% underwent surgery only, 10.3% underwent surgery followed by adjuvant chemotherapy, and 10% underwent radiation after surgery. Five-year cancer-specific survival was 15.2% with surgery alone, and combined surgery and chemotherapy provided the highest percentages (38.3% and 34.7%, respectively). Females had significantly higher 1- and 5-year cancer-specific survival rates compared to males (59.3% and 29.9% vs. 48.0% and 23.7, respectively; p < 0.001). Well-differentiated tumors had significantly higher survival compared to other gradings (p < 0.001). Survival decreased as tumor staging moved distally from localized to regional to distant (p < 0.001). Metastasis to bone, liver, brain, and lung significantly decreased survival in comparison to patients who did not have any metastasis (p < 0.001). Females had significantly shorter survival compared to their counterparts when metastasis was to the bone, brain, or liver (p < 0.001). Multivariate analysis identified male sex (Hazard Ratio (HR) = 1.2), undifferentiated grade (HR = 1.9), regional extent of disease (HR = 1.7), distant extent of disease (HR = 3.7), and metastasis to liver (HR = 3.5) as variables associated with worse survival.

CONCLUSION

Combined SCLC is overall very rare. However, the frequency of presentation with combined SCLC is on the rise, in part due to improvements in diagnostic techniques. Despite advances in therapies, treating combined SCLC is challenging, and novel therapies are not utilized, owing to low rates of targetable mutations. Combined SCLC has higher survival rates if well differentiated.

Combined SCLC clinical and pathological aspects

Combined small cell lung carcinoma (C-SCLC) is rare and accounts for 1-3% of all lung cancer cases. Although its incidence has increased recently, there are limited studies on it. The records of patients admitted to our hospital between January 2015 and December 2019 and diagnosed with histologically proven combined small cell were scanned retrospectively and reviewed. 31 patients were analyzed. The average follow-up time was 10 months. The radiotherapy (RT) rate, surgery rate, and large cell malignancy rate were significantly lower in the ex group than in the living group (p=0.024, p=0.023, p=0.015). The rates of extensive disease, metastasis, and thyroid transcription factor 1 (TTF1) were significantly higher in the old group than in the living group (p=0.000, p=0.000, p=0.029, respectively). In the univariate model, sequential RT, fatigue, lactate dehydrogenase (LDH), stage, metastasis, contralateral lung metastasis, chemotherapy were observed to be significantly effective in predicting survival time (p=0.000, p=0.050, p=0.011, p=0.004, p=0.004, p=0.045, p=0.009).  In the multivariate model, independent (p=0.015, p=0.022, p=0.049) efficacy of RT, stage, and chemotherapy in predicting survival was observed. C-SCLC is a specific mixed carcinoma and reports evaluating this type are still scarce. The stage of the disease, radiotherapy and chemotherapy are extremely important in predicting survival.

Small cell lung cancer transformation: From pathogenesis to treatment

Small cell lung cancer (SCLC) is a type of neuroendocrine tumor with high malignancy and poor prognosis. Besides the de novo SCLC, there is transformed SCLC, which has similar characteristics of pathological morphology, molecular characteristics, clinical manifestations and drug sensitivity. However, de novo SCLC and transformed SCLC have different pathogenesis and tumor microenvironment. SCLC transformation is one of the mechanisms of resistance to chemotherapy, immunotherapy, and targeted therapy in NSCLC. Two hypotheses have been used to explain the pathogenesis of SCLC transformation. Although SCLC transformation is not common in clinical practice, it has been repeatedly identified in many small patient series and case reports. It usually occurs in epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma after treatment with tyrosine kinase inhibitors (TKIs). SCLC transformation can also occur in anaplastic lymphoma kinase (ALK)-positive lung cancer after treatment with ALK inhibitors and in wild-type EGFR or ALK NSCLC treated with immunotherapy. Chemotherapy was previously used to treat transformed SCLC, yet it is associated with an unsatisfactory prognosis. We comprehensively review the advancements in transformed SCLC, including clinical and pathological characteristics, and the potential effective treatment after SCLC transformation, aiming to give a better understanding of transformed SCLC and provide support for clinical uses.

Case Report: Combined Small Cell Lung Carcinoma With Pulmonary Adenocarcinoma

Background

Combined small cell lung carcinoma is defined as cancer tissues that mainly contain small cell lung cancer (SCLC) components with non-SCLC (NSCLC) histopathological types. The most common part of NSCLC is squamous cell carcinoma or large cell carcinoma. Combined SCLC (CSCLC) contains adenocarcinoma is extremely rare.

Case Presentation

We reported a case with surgically treated diagnosed as CSCLC with adenocarcinoma in an elderly and we summarized the clinical features of this disease. The patient has remained well for over 2 weeks after the treatment.

Conclusion

There are still few research reports on CSCLC. Since the survival time of patients with advanced CSCLC is shorter than that of simple SCLC, the recommended treatment for CSCLC is early detection and early surgery. In order to facilitate preoperative diagnosis and avoid misdiagnosis of such rare diseases, more cases need to be reported.

Clinicopathological Difference and Survival Impact of Patients with c-SCLC and SCLC

Background

Combined small cell lung cancer (c-SCLC) distinguishes itself from small cell lung cancer (SCLC) due to its inclusion of both SCLC and non-small cell lung cancer (NSCLC) components. Few studies have compared clinicopathological characteristics, prognosis and factors affecting survival. We therefore addressed the issues in this study.

Patients and Methods

A total of 400 c-SCLC and 20,841 SCLC patients were enrolled using SEER database. Difference in clinicopathological characteristics of SCLC and c-SCLC patients was analyzed using chi-square. Kaplan–Meier was applied to compare their survival before and after propensity score matching (PSM). Cox regression model was adopted to assess the impact of different clinical variables on survival. Logistic regression was applied to identify risk factors for c-SCLC and SCLC patients.

Results

Differences in race, sex, T stage, N stage, surgery, bone, brain and liver metastasis were detected between c-SCLC and SCLC patients. c-SCLC patients had better overall survival (OS) than SCLC patients before PSM. Age, race, sex, T stage, N stage, surgery, bone, brain, liver and lung metastasis were prognostic factors affecting OS for c-SCLC and SCLC (P < 0.05). However, a significant OS benefit was not observed in c-SCLC after adjusting for clinicopathological variables (HR, 0.950; 95% CI, 0.842–1.073; P=0.411). No significant OS difference was found between c-SCLC and SCLC patients after PSM (P = 0.789). c-SCLC patients had lower risk of lymph node (OR: 0.555; 95% CI: 0.439–0.703; P < 0.001) and liver metastasis (OR: 0.591; 95% CI: 0.448–0.779; P < 0.001), whereas had no significant differences in bone and brain metastasis risks (P > 0.05) compared with SCLC patients.

Conclusion

The prognosis of c-SCLC did not significantly differ from that of SCLC if clinicopathological characteristics are controlled. Better prognosis for c-SCLC patients over SCLC patients may be ascribed to fewer liver and lymph node metastases upon diagnosis.

The Value of 18F-FDG PET in the Diagnosis of Intertrabecular Vertebral Metastasis in a Small Cell Lung Cancer Patient with a High Serum CEA Level

We encountered a small cell lung cancer (SCLC) patient with intertrabecular vertebral metastasis (IVM). A 59-year-old man was admitted to our hospital with weight loss. ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET)-CT demonstrated the uptake of fluorodeoxyglucose in the hilum of the left lung and whole-body bones. Despite intensive support, the patient died within a month. Subsequent autopsy revealed a small lesion consisting of small round cells in the left lung. The cancer cells were found to have spread through the replacement of the bone marrow cells while sparing the trabecular bone. This case demonstrated the potential of ¹⁸F-FDG PET for detecting IVM in SCLC patients.

Combined small-cell lung carcinoma

Currently, studies assessing combined small-cell lung carcinoma (C-SCLC) are relatively scarce and limited. Indeed the clinicopathological features, treatment, and prognosis of patients with C-SCLC have not been fully determined. The incidence of C-SCLC ranges from 5%–28% in different studies, which is related to the specimen types used. The clinical features of C-SCLC are characterized by the higher proportion of peripheral locations, earlier stage, and more opportunity to experience surgery. Surgery is more important for earlier stage C-SCLC. There have been no recent changes in the chemotherapy of C-SCLC, which is recommended by the treatment guidelines for SCLC, neither showing survival benefit from the 3-agent regimen. Meanwhile, the efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in EGFR-mutated C-SCLC patients remains inconclusive. This review focuses on clinical and pathologic features, prognostic factors, and optimized treatment model in C-SCLC.

The role of prophylactic cranial irradiation in surgically resected combined small cell lung cancer: a retrospective study

Background

Combined small cell lung cancer (C-SCLC) is defined as small cell lung cancer (SCLC) combined with any of non-small cell lung cancer (NSCLC) histological types, such as large cell carcinoma, squamous cell carcinoma, or adenocarcinoma. Since C-SCLC is an increasingly recognized subtype of small cell carcinoma, we conducted a retrospective study in our institution to explore the value of prophylactic cranial irradiation (PCI) in patients with C-SCLC treated by surgery.

Methods

Between 2005 and 2014, the records of all consecutive patients with pathologically diagnosed C-SCLC after surgery in our institution were reviewed. Overall survival (OS), disease-free survival (DFS), and brain metastasis free survival (BMFS) were estimated by Kaplan-Meier method. Survival differences were evaluated by log-rank test, while multivariate analysis was performed by a Cox proportional hazards model.

Results

Of the total 91 patients included in this analysis, 11 patients (12.1%) were in PCI group and 80 (87.9%) in non-PCI group. The 5-year cumulative incidence of brain metastasis in the whole group was 22.2% (26.3% in non-PCI group vs. 0% in PCI group), and 5-year OS rate was 44.1%. Patients treated with PCI had significantly longer OS (P=0.011) and DFS (P=0.013), also had the trend to live a longer BMFS with marginal significance (P=0.092) than non-PCI-treated patients. The multivariate analysis showed that PCI [hazard ratio (HR) =0.102, P=0.024] was one of independent prognostic factors of the OS in surgery-treated C-SCLC patients.

Conclusions

C-SCLC patients have a relative high risk of developing brain metastases based on our study. These data showed that PCI could improve OS and DFS, as well as tend to decrease brain metastases in surgically resected C-SCLC. However, whether PCI could be part of comprehensive treatment modalities in C-SCLC should be assessed in prospective studies.

Human epididymis protein 4 may not be a reliable screening biomarker for detecting lung carcinoma patients

Human epididymis protein 4 (HE4) acts as a protease inhibitor. It has been detected in the serum of patients with lung cancer patients and its utility for lung cancer screening was found in different studies. Nevertheless, little is known regarding the expression of HE4 in lung carcinoma subtypes. The aim of the present study was to investigate whether HE4 expression is a reliable marker for detecting any lung carcinoma subtypes, including small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC) and adenocarcinoma (AC). In total, 141 lung carcinoma patients were enrolled in the study. Biopsy samples were obtained from bronchoscopic biopsy. The tumors were classified as SCLC (group 1, 54 cases) or NSCLC (group 2, 87 cases) based on histology and immunohistochemistry. The latter was sub-grouped as adenocarcinoma (group 2a, AC) and squamous cell carcinoma (group 2b, SCC). The immunohistochemical expression of HE4 was compared between the groups. The study revealed that the majority of the SCLC and SCC cases were devoid of HE4 (90.1 and 89.65%, respectively). Approximately 10% of cases had HE4 immune expression and the staining was focal and moderate throughout the tumor tissue. On the other hand, 78.8% of AC expressed HE4 and the staining was diffuse and strong. The overall HE4 expression in the lung cancer patients was 33.7%. In conclusion, the results of the present study have shown that HE4 is expressed in adenocarcinoma of the lung but it is not frequent in SCC and SCLC. The value of HE4 as a screening biomarker for lung cancer is limited but its presence exclusively in adenocarcinoma may provide new insight for targeted therapy.

Clinical outcomes of surgically resected combined small cell lung cancer: a two-institutional experience

BACKGROUND

The combined small cell lung cancer (c-SCLC) was rare and its clinicopathological characteristics had not been thoroughly described. The aim of this study was to determine prognostic factors and survival in c-SCLC patients.

METHODS

Clinical records of patients with c-SCLC who underwent surgery between January 2009 and December 2013 in two institutions were retrospectively reviewed.

RESULTS

Ninety-seven patients were identified. The most common pathology was combined SCLC and large cell neuroendocrine carcinoma (LCNEC, N=46), followed by combined SCLC and squamous cell carcinoma (SCC) (N=32), combined SCLC and adenocarcinoma (AC) (N=12), and combined SCLC and adenosquamous carcinoma (ASC) (N=7). The overall survival (OS) rates of the entire cohort were 42.4% and 35.2% at 3 and 5 years, respectively. Multivariate analysis identified sex [female vs. male, hazards ratio (HR) =0.38; 95% confidence interval (CI): 0.19-0.79; P=0.010], age (<53 vs. >53 years, HR =0.28; 95% CI: 0.09-0.81; P=0.019), performance status (<2 vs. >2, HR =0.08; 95% CI: 0.02-0.32; P<0.001), combined non-small cell lung cancer (NSCLC) components (LCNEC vs. non-LCNEC, HR =3.00; 95% CI: 1.03-8.76; P=0.045), adjuvant therapy (yes vs. no, HR =0.33; 95% CI: 0.17-0.67; P=0.002) as significantly prognostic factors of OS in patients with complete resection and lymphadenectomy.

CONCLUSIONS

The mixed NSCLC components within c-SCLCs had a significant influence on the survival. Compared with surgery alone, adjuvant therapy was associated with significantly improved survival in patients with complete resection and lymphadenectomy.

Mixed Neuroendocrine-Nonneuroendocrine Neoplasms (MiNENs): Unifying the Concept of a Heterogeneous Group of Neoplasms

The wide application of immunohistochemistry to the study of tumors has led to the recognition that epithelial neoplasms composed of both a neuroendocrine and nonneuroendocrine component are not as rare as traditionally believed. It has been recommended that mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are classified as only those in which either component represents at least 30 % of the lesion but this cutoff has not been universally accepted. Moreover, since their pathogenetic and clinical features are still unclear, mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are not included as a separate clinicopathological entity in most WHO classifications, although they have been observed in virtually all organs. In the WHO classification of digestive tumors, mixed neuroendocrine-nonneuroendocrine neoplasm is considered a specific type and is defined as mixed adenoneuroendocrine carcinoma, a definition that has not been accepted for other organs. In fact, this term does not adequately convey the morphological and biological heterogeneity of digestive mixed neoplasms and has created some misunderstanding among both pathologists and clinicians. In the present study, we have reviewed the literature on mixed neuroendocrine-nonneuroendocrine epithelial neoplasms reported in the pituitary, thyroid, nasal cavity, larynx, lung, digestive system, urinary system, male and female genital organs, and skin to give the reader an overview of the most important clinicopathological features and morphological criteria for diagnosing each entity. We also propose to use the term "mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN)" to define and to unify the concept of this heterogeneous group of neoplasms, which show different characteristics mainly depending on the type of neuroendocrine and nonneuroendocrine components.