# Causes of Death and Prognostic Factors in Patients with Superficial Esophageal Cancer Curatively Treated by Endoscopic Therapy: A Multicenter Cohort Study

## TL;DR

This study finds that underweight patients with superficial esophageal cancer treated endoscopically face higher non-cancer-related deaths, emphasizing the need for long-term care.

## Contribution

The study identifies low BMI as a novel prognostic factor for non-cancer-related mortality after curative endoscopic therapy for superficial esophageal cancer.

## Key findings

- Low BMI is significantly associated with poorer overall survival due to non-cancer-related mortality.
- Five-year survival rates differ by treatment indication categories, with the lowest in 'beyond-indication' cases.
- Advanced age and low BMI are independent risk factors for mortality after curative endoscopic treatment.

## Abstract

Endoscopic resection is an established curative treatment for superficial esophageal cancer and provides excellent disease-specific survival. However, in clinical practice, we have often experienced that patients who undergo curative endoscopic resection are subsequently lost due to causes unrelated to esophageal cancer. This clinical observation prompted us to investigate factors affecting long-term outcomes beyond cancer control. In this study, we evaluated the impact of body mass index (BMI) on survival after curative endoscopic resection. Although disease-specific survival was excellent across all BMI categories, a lower BMI was significantly associated with poorer overall survival, primarily due to increased non-cancer-related mortality. These findings highlight the importance of long-term surveillance and comprehensive patient management, particularly for underweight patients, even after curative endoscopic treatment.

Background: Endoscopic resection has become a standard curative treatment for superficial esophageal cancer. However, limited data are available regarding long-term outcomes and causes of death after curative endoscopic treatment, particularly deaths unrelated to the primary esophageal cancer. This study aimed to clarify post-treatment prognosis and to identify factors associated with mortality in patients with superficial esophageal cancer who underwent curative endoscopic resection. Methods: We conducted a multicenter cohort study in Japan to evaluate survival outcomes, causes of death, and prognostic factors in patients with superficial esophageal cancer who achieved curative resection by endoscopic treatment. Patients were stratified according to endoscopic treatment indication categories (absolute, relative, and beyond indication). Five-year overall survival and disease-specific survival were analyzed, along with risk factors for all-cause and cause-specific mortality. Results: No disease-specific deaths were observed in patients with absolute or relative indication lesions, whereas the disease-specific 5-year survival rate was 81% in patients with beyond-indication lesions. When overall mortality, including deaths from other diseases and other malignancies, was evaluated, the 5-year survival rates were 92% for absolute indication cases, 85% for relative indication cases, and 69% for beyond-indication cases. Multivariate analysis identified low body mass index (BMI) and advanced age as independent risk factors for mortality. Notably, low BMI was significantly associated with non-cancer-related death. Conclusions: Even among patients who achieve curative endoscopic treatment for superficial esophageal cancer, long-term survival is limited by deaths from other malignancies and non-cancer-related causes. Low BMI represents a clinically important prognostic factor, underscoring the need for comprehensive post-treatment surveillance and supportive care beyond cancer control.