Endoscopic radiofrequency ablation (RFA) appears to be a safe and effective treatment for flat-type noninvasive squamous neoplasia of the esophagus. However, if RFA is applied to lesions containing invasive cancer (esophageal squamous cell carcinoma [ESCC]), histological features associated with lymph node metastases may remain undetected. In addition, extension of neoplasia down the ducts of esophageal submucosal glands (SMGs) may create a sheltered “niche” beyond the reach of ablation.

To determine the RFA eligibility of flat-type ESCC.

Retrospective analysis of prospectively collected data of ESCC patients.

National Cancer Center Hospital, Tokyo, Japan.

Patients with flat-type ESCC larger than 3 cm removed by endoscopic submucosal dissection (ESD).

Three endoscopists involved in RFA studies in China reviewed endoscopic images to select lesions eligible for RFA. Corresponding ESD resection specimens were histologically examined.

The presence of poor histological features (ie, invasion in m3 or deeper, poor tumor differentiation, or lymphovascular invasion) and the number of involved esophageal SMGs and ducts.

Sixty-five lesions were included, 17 (26%) of which qualified as RFA eligible by RFA endoscopists. Interobserver agreement for this assessment was poor (κ = 0.09). Six of the 17 specimens (35%) showed relevant disease: 4 lesions invaded in the muscularis mucosae, 1 of which also showed lymphovascular invasion; 2 lesions showed extension of neoplasia into SMGs.

Limited number of cases. RFA eligibility status was based on analysis of still images.

One third of flat-type ESCC, deemed eligible for RFA, demonstrated histological features that are considered (relative) contraindications to endoscopic treatment. Because it appears difficult for endoscopists to identify low-risk ESCC, conservative use of RFA for flat-type ESCC is advocated until long-term follow-up data are available.