Surgery for Gastric Cancer
Fabio Pacelli, M.D. Antonio Sgadari, M.D. G.B. Doglietto, M.D.
Catholic University School of Medicine 00168 Rome, Italy
N Engl J Med 1999; 341:538-539
To the Editor: The results of the randomized trial comparing extended (D2) and limited (D1) lymph-node dissection for gastric cancer, reported by Bonenkamp et al. (March 25 issue), should be interpreted with caution. Patients in the D2 group had a higher in-hospital death rate than those in the D1 group. It has already been suggested that the learning curve and protocol design (removal of the pancreatic tail in patients with a proximal tumor who were undergoing a D2 dissection) account for the difference. The high percentage of in-hospital deaths in the D2 group might have introduced a bias in the estimate of long-term survival. The excess early mortality in the D2 group may explain, at least in part, the small difference in the survival rate between the two groups at five years. Using data from Table 2 of the report by Bonenkamp et al., we estimated the risk of death for patients in each group: the relative risk was 1.04 (95 percent confidence interval, 0.9 to 1.2) for the patients in the D1 group as compared with those in the D2 group when in-hospital deaths were included; when these deaths were excluded, it was 1.11 (95 percent confidence interval, 1.0 to 1.3). These calculations suggest that the inclusion of in-hospital deaths biased the difference toward the null hypothesis. The high rate of protocol deviations also might have reduced the ability to detect differences between the two treatments. The authors acknowledged this problem in an interim reportbut gave no information about the number and sites of dissected nodes. The conclusions of the paper that D2 dissection is unsafe and does not improve long-term survival are debatable, because they may have a negative influence on Western surgeons who treat this curable disease. Indeed, extended lymphadenectomy can be safely and effectively performed by Western surgeons.The introduction of techniques that preserve the pancreas has reduced postoperative complications.The argument that differences in survival might reflect stage migration is contradicted by the persistent differences when overall survival curves are compared, regardless of staging.