Treatment options and prognosis of patients with lung squamous cell cancer in situ: a comparative study of lung adenocarcinoma in situ and stage IA lung squamous cell cancer

BACKGROUND: Lung squamous cell cancer in situ (LSCIS) is preinvasive squamous tumor and generally overlooked as a potential subtype of pathological and clinical significance, which has seldom been investigated systematically. This study sought to explore the clinical features, prognostic factors, and optimal treatments for LSCIS patients. METHODS: Patients diagnosed with LSCIS (n=449), lung adenocarcinoma in situ (LAIS; n=1,132), stage IA lung squamous cell cancer (LSQCC; n=22,289) and stage IA lung adenocarcinoma (LUAD; n=68,523) were identified in the Surveillance Epidemiology and End Results (SEER) database. Additionally, 512 patients from the Shanghai Pulmonary Hospital diagnosed with LSCIS (n=34), LAIS (n=248), stage IA LSQCC (n=118) and stage IA LUAD (n=112) were included in the study. Kaplan-Meier survival curves were constructed, and Cox proportional hazards regression analyses were performed to examine the overall survival (OS), lung cancer-specific survival (LCSS), and progression-free survival (PFS) of the patients. RESULTS: The univariate and multivariate analyses showed the patients with LSCIS had significantly worse survival than those with LAIS. Although, the univariate analysis revealed that the LSCIS patients had significantly worse OS and LCSS than the stage IA LSQCC patients, the multivariate analyses showed that the prognosis of the LSCIS was similar to that of the stage IA LSQCC in the SEER cohort. The prognosis of the LSCIS was similar to that of the stage IA LSQCC in the Shanghai Pulmonary Hospital cohort. The univariate and multivariate analyses showed that age (>70 years) and chemotherapy were negative prognostic factors, and surgery was a favorable prognostic factor for the LSCIS patients. The survival of the LSCIS patients who underwent local tumor destruction or excision was similar to that of those who did not receive surgery. Lobectomy was the surgical procedure associated with the highest OS and LCSS in LSCIS patients. CONCLUSIONS: The survivals of the LSCIS were similar to those of the stage IA LSQCC, but significantly worse than those of the LAIS. Surgery was an independent favorable prognostic factor for the LSCIS patients. Lobectomy was a superior choice of surgical procedure, and significantly improved the current outcomes of the LSCIS patients.