Comparative Effectiveness of Adjuvant Chemotherapy versus Observation in Stage IB Squamous Cell Lung Carcinoma: A Propensity-Matched Real-World Analysis

Botao Liang¹Tingting Fu²Juntang Guo³Lianbin Zhang³Chaoyang Liang³Tao Zhang³Kai Zhao⁴Zhaofeng Gao⁵Jing Yang²Leilei Shen^4*

• ¹Traditional Chinese and Western Medicine Hospital, tianshui, China
• ²1st Medical Center of Chinese PLA General Hospital, Beijing, China
• ³Department of Thoracic Surgery, People 's Liberation Army General Hospital, Beijing, China
• ⁴Hainan Hospital of Chinese PLA General Hospital, Sanya, China
• ⁵Nankai University School of Medicine, Tianjin, China

Background: The value of adjuvant platinum-based chemotherapyadjuvant chemotherapy (ACT) in stage IB squamous cell carcinoma (SqCC) remains controversial. Methods: This retrospective study enrolled patients with surgically resected stage IB SqCC between January 2013 and August 2024. Clinicopathological characteristics and survival data were collected. To mitigate the impact of observed confounders, propensity score matching (PSM) was performed using clinically relevant covariates, including age, sex, tumor diameter, poor differentiation, spread through air spaces, visceral pleural invasion, and lymphovascular invasion, resulting in 46 well-matched patient pairs. The primary endpoint was disease-free survival (DFS). The secondary endpoint was overall survival (OS). Results: A total of 181 patients were enrolled in the study. Among them, 50 patients (27.6%) received adjuvant chemotherapy (ACT), while 131 patients (72.4%) were assigned to the clinical observation (CO) group. The ACT group had more patients <65 years (P=0.007), larger tumors (P<0.001), and more poorly differentiated tumors (P=0.017) compared with the CO group. The two groups were comparable after PSM. Among the ACT group, twenty-eight (56%) patients received cisplatin plus docetaxel regimen. 16% (8/50) of patients took cisplatin plus gemcitabine regimen, and carboplatin plus paclitaxel was 14 (28%) patients' option. The median follow-up time was 60 months (range: 5-137 months). The 5-year DFS rates were 84.8% in the ACT group and 85.6% in the CO group (HR: 1.05, 95% CI 0.44-2.51; P=0.919). There was no statistically significant difference in DFS between groups, both in the entire cohort 3 (P=0.701) and the matched cohort (P=0.665). The 5-year OS rates were 96.8% in the ACT group and 93.1% in the CO group (HR: 2.46, 95% CI 0.72-8.35; P=0.150). No statistically significant difference in OS was observed, either in the overall cohort (P=0.131) or in the matched cohort (P=0.300). Conclusions: ACT may not confer significant survival benefits in resected stage IB SqCC, with comparable disease-free and overall survival outcomes observed between treatment and observation groups.