Features of recurrence of endometrioid type endometrial cancer of I stage

The aim of this study was to determine the rates of recurrences of stage I endometrial cancer (EC) and features of their localization depending on the clinical and pathological characteristics of the tumor and methods of patients' treatment.

The study included 968 patients with stage I endometrioid EC, who underwent surgical treatment in the Department of Oncogynecology of the National Cancer Institute in 2015-2019. Surveillance of patients lasted from January 2015 to December 2020, with a minimum follow-up period of 1 year from the date of surgery. Adjuvant radiation or chemotherapy was performed depending on the clinical and pathological characteristics of the EC case.

During the follow-up period, recurrences were observed in 7.0% of cases and were most often found in stage IC of low differentiation grade. It was found that during surgical treatment without adjuvant therapy relapses occurred in 12-36 months after the start of treatment, with adjuvant radiation therapy - in 6-18 months, and with adjuvant chemotherapy - in 32-60 months. Recurrences most often occurred in patients with EC who underwent surgical treatment in combination with chemotherapy (p < 0.05). The lowest number of recurrences was recorded among patients who underwent surgery as an only treatment. The best 5-year survival rate was observed in the group of patients with surgical treatment (93%), and the worst - in the patients treated with combination of surgery and chemotherapy (57%). In patients without recurrences, the survival rate after treatment was 97%, while in patients diagnosed with relapses, the survival rate was 65%.

Despite the predominantly favorable course of EC stage I, some patients develop relapses. The rate and localization of recurrences depend on the histological structure of the tumor and treatment regimens of the EC patients.