Reply to M. Fujishiro

Fujishiro et al. suggest CT with abdominal ultrasonography at least every 3 months during the 1st year after endoscopic submucosal dissection (ESD) of m3 lesions. This is a very important suggestion because endoscopic mucosal resection (EMR)/ESD for early gastrointestinal cancer should be curative for patients with absolute indications for this treatment. As EMR/ESD has widely been performed [1], it is a matter of concern that there are a number of cases in which postoperative diagnosis of the lesions showed that they were not among those for which EMR/ESD is absolutely indicated - preoperative diagnosis is not always accurate. Our study showed that patients with histologically confirmed m3 esophageal squamous cell carcinoma (m3-ESCC) had a 5-year survival rate at 95 % if they were diagnosed as N0M0 on the basis of thorough preoperative examinations [2]. This implies that follow-up without additional treatment could be the treatment option for patients with m3-ESCC, because they have a low risk of lymph node metastasis.

Clinically, there are two patterns of histological confirmation of the diagnosis m3-ESCC after EMR/ESD. One pattern is that a lesion is diagnosed preoperatively as less infiltrative (i. e., an absolute indication for EMR/ESD) and then m3 is diagnosed postoperatively. In such cases, since the lesion is treated as though an absolute indication existed but is then diagnosed as m3, additional treatment should be considered with the risk of lymph node metastasis taken into consideration. For additional treatment, surgery is now recognized as the standard therapy. According to the report by Oyama et al., low-risk lesions have a 4.3 % risk of metastasis [3], which conversely indicates that metastasis will not occur in 95 % of the patients. Considering the invasiveness of surgery, a follow-up without treatment is one of the options for such patients.

The other pattern is that a lesion is initially diagnosed as m3 or deeper but EMR/ESD is selected on the basis of the patient’s wishes and the potential risk. When the lesion is finally diagnosed as less infiltrative than m3 (m1 - 2) postoperatively, a follow-up without additional treatment is reasonably selected because the risk of lymph node metastasis is low. However, in cases of m3-ESCC, selecting the best treatment is of great importance clinically. Treatment options selected in the cases mentioned above, when the m3 diagnosis is made after EMR/ESD, are applied in some cases. However, it is critical in such cases to make a careful diagnosis of lymph node swellings in the neck, chest, and abdomen by preoperative staging using CT and endoscopic ultrasonography. Should lymph node swelling be recognized by preoperative examinations, the lesion is diagnosed as stage IIB [4], and surgery, as the standard treatment, should be selected. To date, there is no evidence as to the optimal interval for examination of micrometastases that cannot be detected by CT or EUS. Taking the frequency and speed of growth as well as cost-effectiveness into consideration, a follow-up at least every 6 months may be sufficient.

The most important issue is: what should be done when lymphatic metastasis is confirmed during follow-up? The best treatment at that point should be selected. When a patient exhibits lymphatic metastasis only in the abdomen, surgery is one option. Even in a case unfitted for surgery, some patients could achieve a complete response by receiving chemoradiotherapy. Otherwise, palliative chemotherapy could be another option. We endoscopists should not only commit ourselves to resection, but also provide treatment with a view to the subsequent treatment strategy. Considering these possibilities, sufficiently informed consent from the patient is required.

Competing interests: None

References

• 1 Kodama M, Kakegawa T. Treatment of superficial cancer of the esophagus: a summary of the responses to a questionnaire on superficial cancer of the esophagus in Japan.  Surgery. 1998;  123 432-439
• 2 Katada C, Muto M, Momma K. et al . Clinical outcome after endoscopic mucosal resection for esophageal squamous cell carcinoma invading the muscularis mucosae - a multicenter retrospective cohort study.  Endoscopy. 2007;  39 779-783
• 3 Oyama T, Miyata Y, Shimatani S. et al . Lymph nodal metastasis of m3, sm1 esophageal cancer [Japanese with English abstract].  I To Cho. 2002;  37 71-74
• 4 Sobin L H, Wittekind C H. International Union Against Cancer (UICC). TNM classification of malignant tumors, 5th ed.  New York; Wiley 1997: 54-58