Optimal Patient Selection for Primary Tumor Resection in Stage IV Metastatic Lung Squamous Cell Carcinoma: Development and Validation of a SEER-Based Prognostic Nomogram

Objectives Primary tumor resection has been associated with potential enhanced survival in select patients with stage IV metastatic lung squamous cell carcinoma (mLUSCC). However, identifying suitable candidates for surgery remains challenging. This study aimed to develop and validate a prognostic model to select mLUSCC patients likely to benefit from primary tumor resection. Methods Data on stage IV mLUSCC patients were retrieved from the SEER database. Patients were divided into surgery and nonsurgery groups based on primary tumor resection. Propensity score matching (PSM) using covariates including age, T/N stage, grade, metastases, chemotherapy, and others mitigated selection bias. Survival was assessed using Kaplan-Meier curves and Cox proportional hazards models. The surgery group was split randomly (70:30) into training and validation cohorts for model development via multivariate Cox regression. Results Among 18,701 eligible patients, 3.57% (n = 668) underwent primary tumor resection. Post-PSM, median overall survival (mOS) was superior in the surgery group (11 [95% CI: 9–12] vs. 6 [5–6] months; P < 0.0001). The model demonstrated good discriminative ability, with AUCs for 6-, 9-, and 12-month survival of 0.799, 0.746, and 0.744 in the training cohort, and 0.708, 0.727, and 0.667 in the validation cohort. Calibration plots showed excellent agreement between predicted and observed probabilities. Conclusions This validated prognostic nomogram identifies optimal candidates for primary tumor resection in stage IV mLUSCC, providing clinicians with an evidence-based tool for personalized treatment decisions. Further prospective validation is needed.