Retrospective analyses of single-center patient data sets serve really only 1 purpose: to generate hypotheses for prospective studies. By convention, the hypotheses are generated from the statistically significant differences found in the retrospective analysis. In this analysis of nearly 1300 patients with gastric cancer treated in 1 university setting in Korea, the authors have taken a nonsignificant finding (that overall survival of young women is lower than that of older women, with a P value of .33) and generated a hypothesis that sex hormones such as estrogens contribute to the survival differences. While it is possible that there is a real difference in survival but it was not significant because of small sample size (type II error), there are also many other potential confounders, not the least of which are the lack of objective data concerning the hormonal status of the women and the lack of any numeric difference when the age break point was moved 10 years up. The analysis was based on overall survival, not disease-specific survival. If based on the latter, would the significant survival advantage of young men disappear (ie, are the older men dying of other causes)? The administration of adjuvant chemotherapy was not part of the analysis. Perhaps there are some biases within the institution beyond pathological stage that influence the administration of such depending on age and functional status of the patients or the patient's fertility concerns.
Neumayer L. Incidence and Long-term Outcome of Young Patients With Gastric Carcinoma According to Sex—Invited Critique. Arch Surg. 2008;143(11):1067. doi:10.1001/archsurg.143.11.1067