# Impact of endoscopic ultrasonography with fine needle aspiration assessing clinical lymph node staging on radiotherapy treatment planning in esophageal cancer patients

## TL;DR

This study finds that adding EUS-FNA to 18FDG-PET-CT for lymph node staging in esophageal cancer has limited impact on radiotherapy planning and may not be worth the risks.

## Contribution

The study evaluates the real-world impact of EUS-FNA on radiotherapy planning after 18FDG-PET-CT in esophageal cancer patients.

## Key findings

- EUS-FNA altered radiotherapy plans in 13% of patients, with a number needed to treat of 7.5.
- 70% of added lymph node stations based on EUS-FNA showed no positive nodes in surgical specimens.
- Routine EUS-FNA was associated with limited clinical benefit and potential risks, including a fatal case of mediastinitis.

## Abstract

Endoscopic ultrasound (EUS) combined with fine needle aspiration (FNA) can be of additional value to fluorine-18 labeled fluorodeoxyglucose positron emission tomography computed tomography (18FDG-PET-CT) for lymph node staging in esophageal cancer patients. The study objective was to evaluate the impact of routine EUS-FNA after 18FDG-PET-CT staging on radiotherapy planning. Patients with biopsy-proven esophageal carcinoma staged ≥cT2 and eligible for treatment with curative intent, including neoadjuvant chemoradiotherapy (nCRT) or definitive chemoradiotherapy (dCRT), were included. After March 2018, patients who were scheduled for dCRT or ASA 3 were excluded from routine EUS-FNA. The primary outcome was the impact of EUS-FNA after 18FDG-PET-CT on radiotherapy target volume delineation. Subsequently, radiotherapy field modifications were compared with surgical pathology when available. Between 2018 and 2023, 179 patients were included. In 61 patients (34%), the EUS scope was unable to pass through the tumor, limiting lymph node assessment. EUS-FNA altered radiotherapy treatment plans in 24 patients (13%), resulting in a number needed to treat of 7.5. Modifications included expansion of the radiation field in 17 cases, reduction in 6 cases, and both in 1 case. Among surgically resected patients, 10 lymph node stations were added to the radiation field based on EUS-FUNA results. Of these, 7 stations (70%) showed no positive or responsive lymph nodes in the resection specimen, while 3 stations (30%) had 2 positive nodes, and 1 with a complete response to nCRT. Four lymph node stations were with no positive nodes found in the resection specimen. Two patients were readmitted post-procedure, including one fatal case of mediastinitis potentially linked to EUS-FNA. Routine EUS-FNA after18FDG-PET-CT altered radiotherapy plans in only 13% of patients, with limited and uncertain impact on clinical outcomes, especially for those undergoing planned neoadjuvant therapy and surgery. These findings suggest that EUS-FNA may be best avoided in routine practice for such patients.