347 - Differential Prognostic Impact of Distant and Locoregional Recurrence on Survival in Surgically Resected Pathologic N2 NSCLC: Multicenter Dynamic Prediction with Landmark Model

04:10pm - 04:20pm PT

Room 155/157

Presenter(s)

Zeliang Ma, MD - Mayo Clinic Rochester, Rochester, MN

Z. Ma¹, and Z. Hui²; ¹Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, ²Department of VIP Medical Services, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China

Purpose/Objective(s):

Recurrence remains a significant challenge in patients with surgically resected non-small cell lung cancer (NSCLC) following adjuvant chemotherapy. Recurrence status evolves throughout follow-up, dynamically influencing survival outcomes. This study aimed to investigate the differential impact of distant metastasis (DM) and locoregional recurrence (LR) on survival, and to develop prognostic models to tailor postoperative radiotherapy (PORT) and individualize follow-up protocols.

Materials/Methods:

Patients with pN2 NSCLC who underwent complete resection followed by four cycles of platinum-based doublet chemotherapy were included from four academic medical institutions, with treatment periods ranging from 2003 to 2019, varying by center. A dynamic prediction landmark model was constructed to assess the impact of LR and DM on survival. The primary endpoint was overall survival (OS). Baseline factors included age, sex, smoking history, histology, tumor laterality, pT stage, and the number of positive lymph nodes, while DM and LR status were treated as time-dependent covariates.

Results:

A total of 2,120 patients were included in the study, with a median follow-up time of 55.80 months (IQR: 39.47–85.12). The landmark model identified older age, smoking history, advanced T stage, DM, and LR as significant factors associated with worse OS. DM had the most substantial impact on OS (odds ratio [OR], 3.85; 95% CI, 3.32–4.48; P < 0.01), while LR also significantly decreased OS (OR, 2.07; 95% CI, 1.73–2.47; P < 0.01). Multivariate Cox analysis revealed that the pT stage, number of positive lymph nodes, and histology were independently associated with DM. A nomogram was developed to predict the risk of DM for individual patients, categorizing them into three distinct risk subgroups. PORT did not significantly improve OS in the low- or high-risk subgroups but demonstrated a survival benefit in the medium-risk subgroup (hazard ratio [HR], 0.73; 95% CI, 0.63–0.87; P < 0.01).

Conclusion:

The dynamic prediction model estimated future survival probabilities based on individual recurrence status throughout follow-up in patients with surgically resected NSCLC post-chemotherapy. Both DM and LR significantly affected OS, with DM being more detrimental. The DM risk nomogram aids in assessing the benefits of PORT and guiding personalized follow-up strategies.