Long term survival and failure mode analysis of locally advanced lung squamous cell carcinoma

Objective This study investigated long-term survival and identified associated prognostic factors in patients with locally advanced lung squamous cell carcinoma (LSCC).. Methods In this retrospective study, 278 patients with locally advanced LSCC and complete clinical and follow-up records were enrolled. The cohort comprised patients admitted to the Fourth Hospital of Hebei Medical University from January 2012 through December 2019. All statistical analyses, including the use of the χ² test for categorical data comparisons, were performed with IBM SPSS Statistics (version 25.0).The Kaplan-Meier method was applied to calculate OS, PFS1 and PFS2; univariate analysis by Logrank method; Cox model prognosis analysis.Survival curves for OS, PFS1, and PFS2 were generated using the Kaplan-Meier method and compared with the log-rank test. Finally, a multivariate Cox proportional hazards model was applied to identify independent prognostic factors, including all variables that showed significance in the univariate analysis. Results For the entire cohort, the 1-, 3-, 5-, and 10-year overall survival rates were 86.0%, 50.6%, 40.8%, and 24.2%, respectively. The PFS1 rates in the whole group 1、3、5、and 10 years were 63.6%、28.6%、20.8%、and 8.3%, respectively. The PFS2 rates in the whole group 1、3、5、and 10 years were 91.8%、70.9%、56.5%、and 49.4%, respectively. First disease progression: 238 cases of disease progression. Among them, Primary lesion progression 108 (45.3%), mediastinal and supraclavicular lymph node metastases 34 (14.2%), distant metastases 67 (28.1%) ,mixed metastases 29 (12.1%),and oligo metastases 77 (32.3%). Second disease progression: a total of 72 cases. Local progression 24 (33.3%), liver metastasis 6 (8.3%), bone metastasis 13(18.1%), lung metastasis 5(6.9%), brain metastasis 8(11.1%), mediastinal lymph node metastasis 5 (6.9%), adrenal metastasis 3(4.1%) and mixed metastasis 8 (11.1%). Cox multivariate analysis demonstrated that overall survival (OS) was independently predicted by age, lesion location, radiation pneumonitis, first-line treatment efficacy stratification, and PFS1 (all p < 0.05). Meanwhile, PFS1 was independently influenced by radiotherapy efficacy and the actual completed radiotherapy dose (p < 0.05). For PFS2, both PFS1 stratification and first-line treatment efficacy stratification were identified as independent prognostic factors. Conclusion The prognosis of LSCC remains poor; however, an evidence-based, integrated treatment approach can prolong survival. In our study, the choice of concurrent chemoradiotherapy ±consolidation chemotherapy can obtain better objective response rate[ORR（PR+CR）]; the efficacy of first-line therapy and PFS1 are important factors for survival.First-line treatment efficacy reaching CR or PR, PFS1≥12 months, could significantly prolong the survival. Local recurrence and distant metastasis constituted the main patterns of treatment failure. This study demonstrated that initiating radiotherapy early (within 3 months of diagnosis) significantly lowered the rates of these events.