Surgery for small cell lung cancer

Small-cell carcinoma in the setting of pulmonary adenocarcinoma: new insights in the era of molecular pathology

INTRODUCTION

Transformation into small-cell lung carcinoma (SCLC) has been reported as an evolution of lung adenocarcinoma acquiring resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI). However, spontaneous association of SCLC and adenocarcinoma also exists. We sought to compare patients' clinical features and mutation status of EGFR in each tumor component in these conditions.

METHODS

Our study is based on nine consecutive cases of SCLC, occurring synchronously or after a previous diagnosis of pulmonary adenocarcinoma, with or without TKI-based therapy, diagnosed in Marie Lannelongue Surgical Center, France, between 2001 and 2013. Molecular analysis by DNA direct sequencing was performed to detect EGFR mutations on formalin-fixated tissue mostly from surgically resected tumors.

RESULTS

Six patients had a metachronous occurrence of SCLC after adenocarcinoma (2 after TKI); three had a synchronous form. There were four combined SCLCs/adenocarcinomas. Seven adenocarcinoma components were EGFR mutated: five exon 19 deletions and two mutations in exon 21 (L833_V834delinsFL and L858R). Four SCLC components were EGFR mutated. Two cases occurred in never-smoker women with adenocarcinoma treated with TKI: one with E872 mutation in exon 21 and one combined SCLC/adenocarcinoma with exon 19 deletion in both components. Two cases were spontaneous: a SCLC with exon 19 deletion occurring after a nonmutated adenocarcinoma and a combined SCLC/adenocarcinoma with exon 21 mutation (L833_V834delinsFL) in both components.

CONCLUSION

SCLC developing in association with adenocarcinoma, either synchronously or metachronously, seem linked to EGFR mutation, regardless of TKI use. Our findings suggest that such associated cases should be tested for EGFR mutations.

Epidermal growth factor receptor mutation status and clinicopathological features of combined small cell carcinoma with adenocarcinoma of the lung

In lung cancer, somatic mutations of epidermal growth factor receptor (EGFR) are concentrated in exons 18-21, especially in adenocarcinoma (Ad), but these mutations have rarely been reported in small cell lung carcinoma (SCLC). Combined SCLC is rare, and the EGFR mutation status and its relationship to the clinicopathological features of this tumor type have not yet been elucidated. We retrospectively studied six patients with combined SCLC with Ad components among 64 consecutive patients who underwent resection of SCLC. The clinicopathological features of each patient were reviewed, especially for the distribution pattern of the Ad component and lymph node metastases. EGFR mutations were screened by high-resolution melting analysis in each case, and were confirmed by sequencing of each mutation in the microdissected SCLC or Ad components. Regarding EGFR, no specific mutation was detected in five of the six patients, whereas one female patient who had never smoked had a missense mutation. In this case, both the SCLC and Ad components shared the same mutation in exon 21 (L858R). We identified a patient with combined SCLC with Ad sharing an identical EGFR mutation in both the SCLC and Ad components. In addition to the clinicopathological characteristics of this rare histological type of lung cancer, these findings provide useful information for better understanding the biology, natural history and clinical management of SCLC.

CT findings of early-stage small cell lung cancer in a low-dose CT screening programme

The survival of patients with small cell lung cancer (SCLC) is related to T, N, M components, and early diagnosis and treatment of limited stage SCLC may improve survival. The objective of this study was to review the initial and annual repeat screening computed tomography (CT) images of all five patients with SCLC, encountered in our 1996-1998 population-based screening for lung cancer, to clarify any subtle, characteristic CT findings of early-stage small cell lung cancer. The medical records of the patients were reviewed to examine demographic and clinical features. We identified characteristic CT features of SCLC in the lung periphery, which were related to gross pathologic findings with longitudinal spread along the bronchial wall: a small spindle-shaped or pyramidal lesion was found as a subtle CT finding of SCLC, and irregularly shaped nodular lesions (vermiform, pine-cone-like or tandem-like nodular lesions) appeared at a more advanced stage. Tumour volume doubling time of the cases ranged from 38 days to 217 days. All five patients were male smokers: four patients underwent surgery and adjuvant chemotherapy; three of them remain alive, while the remaining patient, an interval case, died of lung cancer. One patient refused treatment and died of a cause other than lung cancer. Annual repeat CT screening was useful for detecting SCLC cases mostly at a curable stage, and information about CT features, presented here, should help physicians identify SCLC at an earlier-stage and lead to a more successful treatment of the disease.

Results of preoperative mediastinoscopy for small cell lung cancer

BACKGROUND

The significance of mediastinoscopy for small cell lung cancer is unclear owing to the small number of surgical cases.

METHODS

To determine the N component of the TNM staging system, computed tomographic findings and the results of mediastinoscopy were compared with the pathologic examination of surgical specimens.

RESULTS

Four cases among 37 patients (10.8%) were determined as inoperable by mediastinoscopy because of mediastinal lymph node metastasis. A thoracotomy was performed in 33 patients. Six patients (18.2%) who had been judged to have no metastasis by mediastinoscopy were found to have N2 disease after examination of the surgical specimens. In the identification of all mediastinal metastases, mediastinoscopy was 40.0% sensitive, 100% specific, and 83.8% accurate. When the superior mediastinal, paratracheal, pretracheal, tracheobronchial, and subcarinal lymph nodes were defined as approachable nodes, mediastinoscopy was 66.7% sensitive, 100% specific, and 94.6% accurate in the evaluation of these restricted nodes. Four cases among 8 patients with cN1 lesions resulted in a designation as pN2.

CONCLUSIONS

Mediastinoscopy is useful for the diagnosis of an approachable mediastinal lymph node in small cell lung cancer cases. This exploration is necessary for patients with small cell lung cancer who are diagnosed as cN1 before thoracotomy.

Surgical results for small cell lung cancer based on the new TNM staging system. Thoracic Surgery Study Group of Osaka University, Osaka, Japan

BACKGROUND

Operation with combined chemotherapy has been recently recommended for very early stage of small cell lung cancer without lymph node metastasis.

METHODS

A retrospective study was undertaken in 91 patients who had undergone pulmonary resection for small cell lung cancer according to the new international staging system.

RESULTS

The 5-year overall probability of survival was 37.1%. The 5-year survival rate was 100% for p-stage 0, 56.1% for p-stage IA, 30.0% for p-stage IB, 57.1% for p-stage IIA, and 42.9% for p-stage IIB. In the p-stage IA-IIB patients who underwent a complete resection, the 5-year survival rate of the patients treated by operation with chemotherapy was better than that of patients treated by operation alone. In addition, the 5-year survival rate of the patients who had four or more courses of chemotherapy was 80.0%.

CONCLUSIONS

These results suggest that operation should be considered for p-stage IA-IIB patients and more than four courses of combined chemotherapy might be desirable in these resectable cases.

Pathological-radiological correlations: pathological and radiological correlation of endobronchial neoplasms: part II, malignant tumors

The majority of lung neoplasms are malignant. Many of these are central and have an associated endobronchial component. Most such neoplasms are of surface epithelial origin; however, neoplasms of submucosal gland, mesenchymal, and lymphoreticular origin may also demonstrate an endobronchial component. Because of their endobronchial location and associated symptoms, these patients often present at an earlier stage than purely parenchymal lung malignancies. The radiographic features in such cases may be similar to those associated with benign endobronchial tumors; however, there are certain radiological signs that are more suggestive of a malignant process. Despite these circumstances, conservative management such as endoscopic excision are inappropriate in most instances. The clinicopathologic and radiological features of these lesions are detailed.