Endoscopic submucosal dissection produces less positive edges than mucosectomy in early gastric cancer

Received: 20-02-10 Accepted: 26-02-10

Dear Dr. Vargas:

We have read the interesting article "Endoscopic treatment of early gastric cancer in Colombia with up to five years of follow up" published in Volume 24 No. 4 of the Colombian Journal of Gastroenterology. In this regard we would like to make the following comments:

1. The histopathological curability criteria of early gastric cancer (GCC) treated by endoscopy are well defined in the literature and include cell differentiation, lymphatic invasion, vascular invasion, negative edges and depth of invasion (1, 2) This series lacks data on lymphatic and/or vascular invasions, making judgment of curability incomplete.

2. Although this study of 11 cases is of vital importance in our environment, it should be emphasized that large studies (3) comparing mucosectomy with endoscopic submucosal dissection (ESD) have shown that ESDs produce less positive edges than do standard mucosectomies, and for this reason have become the currently accepted treatment in Japan (3, 4).

3. Talking about 5 years of follow-up in Sm1 tumors without extension studies (abdominal CAT scans for example) might be inappropriate. It is advisable to obtain extension studies to clearly state the data used for following up Sm1 cases.

4. There are two cases which are reported as Sm1 invasions in the proximal third of the submucosa. How many microns (micrometers) is meant by the proximal third? And, what is the reference?

5. This important work should conclude its comments based on the maximum size of resected tumors (15 mm). This should be stated explicitly in both the title and the conclusion of the investigation.

6. It is necessary to orient the reader of the Colombian Review of Gastroenterology in several ways. How many years did the study last? How many Sm2 cancers were treated endoscopically If they exist in the experience of the authors)? In this way the reader would have a wider range to judge the utility, or lack thereof, of both mucosectomies and ESDs as treatments for CGT (4, 5).

7. Was endosonography performed? What were the results for Sm1 tumors? Or, why was it not performed?

8. It is suggested that the authors guide the reader in the retrospective analysis of the 10 mm case which resulted in positive edges, but with gastrectomy without histologic injury. What does this case teach us? Does it serve us for the future?

9. The phrase "…from the oncological point of view it could be considered that cancer patients are cured," should be modified to read something like, "... In 5 years of follow-up there has not been any presentation of local endoluminal recurrence diagnosed by endoscopy..." (See reviews 1 and 3).

References

1. I Oda, T Gotoda, H Hamanaka, T Eguchi, Y Saito, T Matsuda, P Bhandari, F Emura, et al. Endoscopic submucosal resection for early gastric cancer: Technical feasibility, operation time and complications from a large consecutive series. Digest Endosc 2005; 17: 54-57.

2. Emura F, Oda I, Ono H. Disección endoscópica de la submucosa (DES). Un procedimiento superior a la mucosectomía para el tratamiento del cáncer gástrico temprano. Rev Col Gastroenterol 2007: 22; 209-216.

3. Ono H, Kondo H, Gotoda T, Shirao K, Yamaguchi H, Saito D, Hosokawa K, Shimoda T, Yoshida S. Endoscopic mucosal resection for treatment of early gastric cancer. Gut 2001; 48: 225-9.

4. Gotoda T. Endoscopic resection of early gastric cancer. Gastric Cancer 2007; 10: 1-11.

5. Emura F, Ricaurte O, Mejia J, Osorio O, Sabbagh L, Oda I, Ono H. ESD for early gastric cancer in Colombia. A western validation of the Japanese experience. Gastrointes Endosc 2009: 69(5): AB178.

Fabian Emura MD, PhD

Emura Center LatinoAmerica, Emura Foundation for the Promotion of Cancer Research. Facultad de Medicina, Universidad de la Sabana. Colombia Bogota, Colombia

Ichiro Oda MD Ichiro Oda, MD

Endoscopy Division. National Cancer Center. Tokyo, Japan