# Leveraging Landmark Analysis for Tailored Surveillance in Stage I Non-Small-Cell Lung Cancer

## TL;DR

This study shows that some stage I lung cancer patients have a low risk of relapse and can have less intensive follow-up, while others need continued monitoring.

## Contribution

The study introduces a tailored, risk-based surveillance strategy for stage I NSCLC patients based on histology and lung nodules.

## Key findings

- Carcinoid and adenocarcinoma without lung nodules had significantly lower relapse and new tumor risks.
- 5-year event-free survivors had excellent 10-year survival but varied late event risks based on stage and nodules.
- Tailored surveillance can reduce follow-up intensity for low-risk patients while maintaining monitoring for high-risk individuals.

## Abstract

This study investigated the long-term outcomes and surveillance patterns in 759 patients who underwent surgery for pathological stage I Non-Small-Cell Lung Cancer (NSCLC). We sought to provide evidence to refine current follow-up guidelines, which often lack specific recommendations regarding the optimal duration of surveillance after curative resection. Crucially, the study found that histology and the presence of lung nodules (LNs) were key determinants of late events. Patients with carcinoid tumors and those with adenocarcinoma without LNs demonstrated a significantly lower risk of relapse and new primary tumors compared to high-risk groups. Focusing specifically on 5-year event-free survivors (5y-EFSs), these patients exhibited excellent conditional 10-year OS (92%), but the risk of late events persisted for those with stage IB disease or pre-existing/new LNs. Based on these findings, we propose a tailored, risk-stratified surveillance strategy. This model supports de-escalating follow-up intensity for patients identified as low-risk (such as those with carcinoid and adenocarcinoma without LNs) while ensuring that high-risk individuals receive continued, intensive monitoring to promptly detect potentially curable late events.

Background: Current guidelines for NSCLC follow-up lack specific recommendations on surveillance duration. This study aims to analyze survival and surveillance data in resected stage I NSCLC. Methods: We retrospectively reviewed 759 pathological stage I NSCLC (9thTNM ed.) patients with no history of lung cancer (LC) undergoing surgery from January 2003 to December 2018. Overall survival (OS), incidence of relapse (IR), and incidence of new primary LC (NP) were analyzed. Long-term effect of follow-up beyond 5 years was assessed by landmark analysis of OS, IR, and NP at 10 years, restricted to individuals alive without relapse or NP at 5 years (5-year event-free survivors, 5y-EFSs). Results: The rates of 10-year OS, 10-year IR, NP incidence, and 5y-EFSs were, respectively, 75%, 18%, 1.1%/year, and 59.1% (449 patients). Carcinoid IA/IB (0–10%) and adenocarcinoma IA/IB without lung nodules (LNs) (8–12%) had a similarly lower risk of relapse (p = 0.5088) compared to adenocarcinoma with LNs (p = 0.0191). Similarly, carcinoid (0–0.2%/year) and adenocarcinoma without LNs (0-0.3%/year) had the same lower incidence of NP (p = 0.8062) compared to patients with LNs (p < 0.0001). The group of 5y-EFSs had a conditional 10-year OS, IR, and NP incidence of 92%, 5%, and 0.8%/year. In 5y-EFSs, 10-year OS was better in carcinoid (100%) and adenocarcinoma (94%, p = 0.0009) patients; 10-year IR was lower in stage IA (4%) vs. IB (10%, p = 0.0444), and NP was lower in patients with no pre-surgery (0.5 vs. 1.5%/year, p = 0.0147) and no post-surgery LNs (0.6 vs. 1.1%/year, p = 0.0202). Conclusions: Based on our results, we propose a tailored surveillance strategy by de-escalating follow-up for low-risk patients while maintaining intensive monitoring for high-risk individuals.