Effect of histological subtype and treatment modalities on T1–2 N0–1 small cell lung cancer: A population‐based study

Abstract

Background Combined small cell lung cancer (C‐SCLC) is rare and its clinical features, appropriate treatment, and prognosis are poorly understood. Reports conflict over the prognosis of C‐SCLCs compared to pure small cell lung cancer. Methods The records of patients diagnosed with primary SCLC from 1988 to 2014 were extracted from the Surveillance, Epidemiology, and End Results database. The general features of C‐SCLCs were compared to those of SCLCs. T1–2 N0–1 data was extracted and the effects of the histological subtype, treatment modality, and other prognostic factors on lung cancer‐specific survival (CSS) was analyzed in a 3:1 matched dataset. Analysis was performed using the 8th edition tumor node metastasis staging system and previous staging systems adjunctively. Results C‐SCLCs comprised 1.5% of all SCLCs (1486/98 667); 184 cases of C‐SCLCs and 2681 cases of non‐combined SCLCs (NC‐SCLCs) were included in this study. C‐SCLCs were more likely to be of a higher grade and to occur in the upper lobe than NC‐SCLCs. Before matching, C‐SCLCs showed better CSS (hazard ratio 0.69; P < 0.001). However, stratified Cox proportional hazards analysis in the matched dataset revealed that only treatment modality and age at diagnosis were associated with CSS; the histological subtype had no effect on survival. Of all treatment modalities, surgery with chemoradiation showed the best CSS in T1–2 N0–1 SCLC. Conclusion In early SCLC, surgery with chemoradiation shows the best CSS. C‐SCLC patients might benefit more from multimodal treatments, including surgery, than SCLC patients.

Comparative study of clinicopathological characteristics and prognosis between combined and pure small cell lung cancer (SCLC) after surgical resection

“…Their study determined that C-SCLCs had a more favorable prognosis before and after matching in univariate analysis for lung cancer-specific survival (CSS) than noncombined SCLCs, but there was no significant difference for CSS in multivariate survival analysis, indicating that the histologic subtype was not an independent prognostic factor. 14 Our research results are partially consistent with this study: there was no statistical difference for both RFS and OS of the two subtypes, in both univariate (RFS P = 0.944, OS P = 0.683) (Table S1) and multivariate survival analysis (RFS P = 0.204, OS P = 0.878) ( Figs S1, S2). The inconsistencies in different studies may be due to: (i) the low incidence and detection rate of C-SCLC, resulting in a small sample size and low statistical power; (ii) interpatient heterogeneity due to the additional histological type; and (iii) differences in distribution of disease stage and treatment methods.…”

“…For C‐SCLC, two basic questions remain: Are there any differences in clinical characteristics and prognosis of C‐SCLC compared with P‐SCLC? Should different treatment strategies be applied for the two subtypes? 14 For the first question, we found that the average age of patients with C‐SCLC was higher than that for patients with P‐SCLC, and there were more patients with a smoking history. Although the statistics of the two factors did not reach the threshold for significance, the standard mean difference (SMD) of both factors was greater than 0.1 (age SMD = 0.327, smoking SMD = 0.333) (Table 1).…”

“…In a few studies which used a Caucasian cohort, large cell carcinoma was reported to be the most common component, where inconsistency may be explained by ethnic differences 4, 6 . A previous study reported that the C‐SCLC was mainly located in the upper lobe, 14 and in another study that it often appeared as peripheral lung cancer 5 . The incidence of peripheral lesions of C‐SCLCs and other subtypes (including oat cell or intermediate and mixed small cell/large cell) detected by chest x‐ray was 56% and 14%, respectively 5 .…”

“…Currently, C-SCLCs are treated based on SCLC guidelines. 14 In our cohort, 17 (37.0%) C-SCLC patients were treated with platinum-based doublets sensitive to SCLC, with 14 (30.4%) of cases using etoposide and three (6.5%) cases using irinotecan. Of note, nine (19.5%) C-SCLC patients were treated with platinum-based doublet with paclitaxel or vinorelbine, which are more sensitive to NSCLC.…”

Primary tumor standardized uptake value (SUVmax) measured on 18F-FDG PET/CT and mixed NSCLC components predict survival in surgical-resected combined small-cell lung cancer

“…Combined small-cell lung carcinoma (c-SCLC) is defined as small-cell lung cancer (SCLC) combined with an additional component that consists of any of the histological types of non-small-cell lung cancer (NSCLC), including adenocarcinoma (AC), squamous cell carcinoma (SCC), large-cell carcinoma (LCC), or spindle cell, carcinoid and other rare types (Travis 2014 ). C-SCLC is comparatively uncommon and accounts for only 1−3% of all SCLCs (Moon et al 2019 ).…”