Clinical characteristics and prognosis of pulmonary lymphoepithelioma-like carcinoma: A multicentre retrospective study.

Abstract

8044 Background: Pulmonary lymphoepithelioma-like carcinoma (PLELC) is a rare form of squamous lung cancer, and large-scale clinical studies on its clinical features, prognosis at different stages, and outcomes following treatments are limited. Methods: Patients with PLELC diagnosed by pathology from January 2009 to December 2023 at Sichuan Cancer Hospital and Sun Yat-sen University Cancer Centre were retrospectively analysed. Survival curves were estimated using the Kaplan-Meier method, Log-rank tests were used to compare differences between groups, and the Bonferroni method was used to correct the p-value when two-by-two comparisons between multiple groups were involved. Results: A total of 1,106 PLELC patients were included in the study. Most patients were non-smokers (73.4%), and brain metastasis was rare (0.3%). Tumor-specific characteristics showed a low incidence of EGFR mutation (0.6%) but a high prevalence of PD-L1 positivity (71.6%). The median follow-up duration was 31.6 months. The two-year overall survival (OS) rates for stage I, II, III, and IV patients were 99.4%, 97.7%, 92.7%, and 70.4%, respectively, while the five-year OS rates were 94.8%, 88.7%, 70.6%, and 37.8%, respectively. No statistically significant differences in progression-free survival (PFS) or OS were observed between surgery alone and surgery combined with adjuvant therapy in stage I and II patients, or between radiochemotherapy and combined surgery-radiochemotherapy in stage IIIA and IIIB patients. However, in stage IV patients, chemotherapy combined with immunotherapy resulted in significantly better PFS and OS compared to chemotherapy alone. Conclusions: PLELC patients, mostly non-smokers with rare brain metastasis and high PD-L1 positivity, show favorable prognosis, but further research is needed to refine its optimal treatment strategies. PFS and OS in patients with different stages. Stage Number of cases Median PFS (months) 2-year PFS 95% CI 5-year PFS 95% CI Median OS (months) 2-year OS 95% CI 5-year OS 95% CI IA 145 108.3 94.0% 88.9%-99.1% 75.6% 63.2%-88% Incalcu 99.1% 97.3%-100% 95.7% 90.7%-100% IB 56 119.2 78.0% 65.3%-90.7% 65.2% 49.5%-80.9% Incalcu 100.0% 100%-100% 93.5% 84.8%-100% IIA 37 Incalcu 85.4% 70.1%-100% 62.9% 40.9%-85% Incalcu 100.0% 100%-100% 96.2% 88.8%-100% IIB 104 87.9 78.0% 68.6%-87.4% 60.0% 47.2%-72.8% Incalcu 96.9% 93.6%-100% 85.6% 77.1%-94.1% IIIA 213 47.9 70.6% 63.5%-77.7% 42.8% 33.9%-51.7% 161.5 97.9% 95.9%-99.9% 79.7% 72.4%-87% IIIB 132 24.6 51.1% 41.3%-60.9% 21.3% 11.7%-30.9% 83.7 87.9% 81.6%-94.2% 65.3% 54.8%-75.8% IIIC 73 22.0 44.0% 29.5%-58.5% 24.7% 8.4%-41% 53.5 84.9% 75.3%-94.5% 49.4% 31.8%-67% IVA 123 12.0 29.8% 20.4%-39.2% 0.0% 0%-4.5% 50.0 79.3% 70.9%-87.7% 44.1% 30.9%-57.3% IVB 223 9.0 16.0% 10.3%-21.7% 2.7% 0%-6% 33.6 65.4% 58.1%-72.7% 34.1% 24.3%-43.9% Incalcu: Incalculable; CI: confidence interval.