Postoperative radiotherapy for patients with completely resected pathological stage IIIA-N2 non-small cell lung cancer: a preferential benefit for squamous cell carcinoma

Abstract

BackgroundThe beneficial effect of postoperative radiotherapy (PORT) on completely resected pathological IIIA-N2 (pIIIA-N2) non-small cell lung cancer (NSCLC) has been a subject of interest with controversy. The aim of the study was to distinguish the clinical efficacy of PORT on lung adenocarcinoma (LADC) and lung squamous cell carcinoma (LSCC) among pIIIA-N2 NSCLC.Patients and methodsBetween October 2010 and September 2016, 288 consecutive patients with completely resected pIIIA-N2 NSCLC at Beijing Chest Hospital were retrospectively analyzed, which consisted of 194 cases of LADC and 85 cases of LSCC. There were 42 (21.6%) patients treated with PORT in LADC cases and 19 (22.3%) patients treated with PORT in LSCC cases. The 5-year overall survival (OS), loco-regional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS) were calculated using the Kaplan-Meier method. The prognostic factors were determined using Cox’s regression model.ResultsAmong 194 cases of LADC, the 1-, 3-, and 5-year OS in the PORT group were 95.2%, 61.9% and 40.0%, respectively, while in the non-PORT group were 90.1%, 63.3% and 45.0% (p = 0.948). The use of postoperative chemotherapy (POCT) and smoking index ≥ 400 were both prognostic factors of 5-year rates of OS, LRFS and DMFS. On the other hand, among 85 cases of LSCC, the 1-, 3-, and 5-year OS in the PORT group were 94.7%, 63.2% and 63.2%, respectively, whereas in the non-PORT group were 86.4%, 48.5% and 37.1% (p = 0.026). In this group, only the use of PORT was a favorable prognostic factor for 5-year OS, LRFS and DMFS.ConclusionsDue to clinicopathological differences among completely resected pIIIA-N2 NSCLC, PORT may not be suitable to all patients. Our study distinguishes pIIIA-N2 LSCC from LADC by their positive responses to PORT.

The impact of postoperative radiotherapy on the survival of patients with stage III non-small cell lung cancer: A CONSORT-compliant analysis using the SEER database

“…[ 21 ] Based on the findings of Su et al, [ 22 ] postoperative chemoradiotherapy was found to be effective in treating N2-NSCLC patients, especially those with squamous cell lung cancer. Similarly, Tian et al [ 23 ] observed that PORT was beneficial for IIIA/N2 NSCLC patients with squamous cell cancer but not for those with lung adenocarcinoma. The LNR is calculated by dividing the number of positive Lymph Nodes by the total number of Lymph Nodes sampled pathologically, and it is a prognostic metric.…”

Log odds of positive lymph nodes is a robust predictor of survival and benefits from postoperative radiotherapy in stage IIIA‐N2 resected non‐small cell lung cancer

“…It has been reported that a number of clinicopathological factors such as age, gender, grade, T‐stage, chemotherapy and LNR, were all independent risk factors for patients with poor prognosis 15,27–29 . Notably, recent years witnessed an increase in retrospective studies to explore potential candidates with stage IIIA‐N2 disease for PORT 12,28–33 . Furthermore, it was common that the number or ratio of positive nodes was identified as a predictor of responses to PORT in previous studies 12,28,29,33,34 .…”

“… 15 , 27 , 28 , 29 Notably, recent years witnessed an increase in retrospective studies to explore potential candidates with stage IIIA‐N2 disease for PORT. 12 , 28 , 29 , 30 , 31 , 32 , 33 Furthermore, it was common that the number or ratio of positive nodes was identified as a predictor of responses to PORT in previous studies. 12 , 28 , 29 , 33 , 34 For instance, Gao et al 12 found that PORT only exhibited its role in improving survival in stage IIIA‐N2 NSCLC with PLN ≥6.…”

Predictive Risk Factors for Early Recurrence of Stage pIIIA-N2 Non-Small Cell Lung Cancer

“…There is considerable discussion in the medical community about whether patients with pIIIA-N2 NSCLC should receive postoperative radiation. [44][45][46][47] According to some studies, patients in the high-risk group should consider and may benefit from postoperative radiation. However, clinical evidence of its benefit is required to support the claim.…”