Survival benefit of postoperative chemotherapy in stage III lung squamous cell carcinoma based on SEER database analysis through propensity score matching

Abstract

Lung squamous cell carcinoma (LUSC) is a prevalent subtype of lung cancer. This retrospective cohort study aims to explore the effect of postoperative chemotherapy on survival in patients with Stage III LUSC and to assess its heterogeneity across different patient subgroups. Patients diagnosed with postoperative Stage III LUSC between 2010 and 2015 were identified in the Surveillance, Epidemiology, and End Results (SEER) database, and cases with missing information were excluded. The primary outcome measure was overall survival (OS). Propensity score matching (PSM) was employed to balance confounders. Kaplan-Meier (KM) curve was used to assess the OS of patients in different groups. The prognostic risk factors of patients with OS were screened and analyzed through Cox regression analysis. The cohort consisted of 1,784 patients (65.3% receiving chemotherapy), and postoperative chemotherapy was associated with a modest survival benefit: the adjusted hazard ratio (HR) was 0.62 (95%CI: 0.55-0.69, P < 0.001), corresponding to an absolute 5-year OS improvement from 28% (Non-chemotherapy) to 42% (Chemotherapy). Overall, no significant difference was observed in OS between the PSM group and the non-PSM group, except for the variable tumor size, which became significant for OS after matching. Subgroup analyses revealed that chemotherapy improved survival for patients across nearly all characteristics. Univariate and multivariate Cox regression analyses identified marital status, race, gender, and age as significant prognostic factors influencing OS. In conclusion, postoperative chemotherapy significantly ameliorates the survival in most patients with Stage III LUSC, with the most pronounced effects observed in those with N1-2 stage disease and undergoing resection of the lobe, bilobectomy, or pneumonectomy. Our findings provide valuable insights for clinical decision-making and related studies on the application of chemotherapy in patients with Stage III LUSC resection.

Keywords: Chemotherapy; Lung squamous cell carcinoma; Phase III; Propensity score matching; SEER database.

Fig. 1

Flow diagram illustrating the inclusion and exclusion criteria used for patient selection.

Fig. 2

Trends in the overall incidence of LUSC from 2000 to 2019.

Fig. 3

Visualization of PSM to balance baseline features with a caliper of 0.05.

Fig. 4

Survival analysis of patients with Stage III LUSC under different factors and before and after PSM. A: OS analysis of patients with different laterality before (left) and after (right) matching (blue: left; Red: right); B: OS analysis of patients with different tumor sizes before (left) and after (right) matching (dark blue: ≤3 cm; Red: ≥7 cm; green: 3–5 cm; light blue: 5–7 cm); C: OS analysis of patients at different primary sites before (left) and after (right) matching (dark blue: upper lobe; red: lower leaf; green: middle lobe; light blue: other); D: OS analysis of patients with different surgical methods before (left) and after (right) matching (blue: resection of lobe or bilobectomy; red: other; green: pneumonectomy); E: OS analysis of patients who received or did not receive chemotherapy before (left) and after (right) matching (blue: No; red: Yes).

Fig. 5

Subgroup analysis of the association between chemotherapy and prognosis in patients with Stage III LUSC.