Post written by Tomohiro Kadota, MD, PhD, and Tomonori Yano, MD, PhD, from the Department of Gastroenterology and Endoscopy, National Cancer Center Hospital East, Kashiwa, Japan.

This multicenter study focused on the long-term clinical outcomes after endoscopic resection (ER) for superficial esophageal squamous cell carcinoma (ESCC) with pathological invasion of the muscularis mucosae without lymphovascular invasion (LVI).

The metastatic recurrence rate during follow-up in patients with pT1a–muscularis mucosa ESCC without LVI after ER was reported to be 4.3% to 5.6%.¹,² However, these available data are from single-center studies, and multicenter evidence on long-term outcomes in this population is limited.

According to the guidelines, to our knowledge, no clear recommendations have been established regarding additional treatment post-ER in this population, and observation has generally been adopted as the community standard approach. Based on this background, this multicenter, retrospective study aimed to elucidate real-world long-term outcomes of patients with pT1a–muscularis mucosa ESCC without LVI after ER, based on periodic and careful follow-up.

A total of 540 patients were enrolled from 47 institutions participating in the Japan Clinical Oncology Group—Gastrointestinal Endoscopy Study Group. Of these, 485 patients were observed, and 45 underwent chemoradiotherapy (CRT), and 10 had surgery.

The 5-year cumulative recurrence rate (CRR) was 4.9% in the observation group, 2.2% in the CRT group, and 10.0% in the surgery group. Although the differences were not statistically significant, CRR tended to be lower in the CRT group than in the observation group. Despite the large sample size and long-term follow-up, the 5-year CRR in the observation group remained low (4.9%), consistent with previous reports.

These findings suggest that additional CRT may reduce risk of recurrence; however, its potential benefits should be weighed against treatment-related toxicity, which may preclude its routine use in all patients. Notably, 5 patients developed recurrence more than 5 years after ER, indicating that surveillance beyond 5 years may be warranted.

Given that lymph node metastasis is the predominant pattern of recurrence in this population, strategies to facilitate earlier detection and improve risk stratification are needed. More frequent CT surveillance (eg, every 6 months) and use of EUS may improve early detection of lymph node metastasis, and emerging biomarkers such as circulating tumor DNA may help identify patients at higher risk of recurrence.

Overall, our findings support observation as a reasonable management strategy after ER for patients with pT1a–muscularis mucosa ESCC without LVI, given the low recurrence risk.

Cumulative recurrence rate (CRR) curves according to each treatment. The 5-year CRRs of the observation, CRT, and surgery groups were 4.9%, 2.2%, and 10.0%, respectively.

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1. Ishihara R, Arima M, Iizuka, T, et al. Endoscopic submucosal dissection/endoscopic mucosal resection guidelines for esophageal cancer. Dig Endosc 2020;32:452-93. ↩︎
2. Sato D, Kadota, T, Inaba A, et al. Long-term clinical outcome after endoscopic resection of esophageal squamous cell carcinoma invading the muscularis mucosae without lymphovascular invasion. Gastrointest Endosc 2022;95:634-41.e3. ↩︎