Tailoring lymphadenectomy according to the risk of lymph node metastasis in endometrial cancer.

It has been strongly suggested that patients with endometrial cancer with low risk of lymph node metastasis do not benefit from lymphadenectomy and that intermediate-risk/high-risk endometrial cancer patients benefit from complete pelvic and para-aortic lymphadenectomy. This hypothesis needs to be validated by prospective studies. For randomized controlled trials (RCT), heterogeneity of intervention compromises internal validity and non-participation of experienced doctors compromises external validity. As these situations easily occur in randomized surgical trials (RST) intended for high-risk patients, the effects of complicated surgery, such as full lymphadenectomy, might be underestimated in RST. In a famous RST, data for all eligible patients implied that survival outcome for the non-randomized group was significantly better than that for the randomized group. One plausible explanation is that physicians' judgment and experience produce better treatment decisions than do random choices. Although two RCT from European countries showed negative results of lymphadenectomy on prognosis, valuing the care of individual patients may be more important than uncritically adopting the results of RCT. In endometrial cancer, lymphadenectomy must be tailored to maximize the therapeutic effect of surgery and minimize its invasiveness and adverse effects. Two strategies are: (i) to remove lymph nodes most likely to harbor disease while sparing lymph nodes that are unlikely to be affected; and (ii) to perform full lymphadenectomies only on patients who can potentially benefit from them. Here, we focus on the second strategy. Preoperative risk assessments used in Japan and Korea to select low-risk patients who would not benefit from lymphadenectomy are discussed.