Oncologic impact of micrometastases or isolated tumor cells in sentinel lymph nodes of patients with endometrial cancer: a meta-analysis

Purpose There is a gap in knowledge regarding the impact of micrometastases (MIC) and isolated tumor cells (ITCs) found in the sentinel lymph nodes of patients with endometrial cancer. Here, we present a meta-analysis of the published literature on the rate of MIC and ITCs after lymphatic mapping and determine trends in postoperative management. Methods Literature search of Medline and PubMed was done using the terms: micrometastases, isolated tumor cells, endometrial cancer, and sentinel lymph node. Inclusion criteria were: English-language manuscripts, retrospectives, or prospective studies published between January 1999 and June 2019. We removed manuscripts on sentinel node mapping that did not specify information on micrometastases or isolated tumor cells, non-English-language articles, no data about oncologic outcomes, and articles limited to ten cases or less. Results A total of 45 manuscripts were reviewed, and 8 studies met inclusion criteria. We found that the total number of patients with MIC/ITCs was 286 (187 and 99, respectively). The 72% of patients detected with MIC/ITCs in sentinel nodes received adjuvant therapies. The MIC/ITCs group has a higher relative risk of recurrence of 1.34 (1.07, 1.67) than the negative group, even if the adjuvant therapy was given. Conclusion We noted that there is an increased relative risk of recurrence in patients with low-volume metastases, even after receiving adjuvant therapy. Whether adjuvant therapy is indicated remains a topic of debate because there are other uterine factors implicated in the prognosis. Multi-institutional tumor registries may help shed light on this important question.