PROGNOSTIC SIGNIFICANCE OF TUMOR AND DEPTH OF ITS INVASION INTO MYOMETRIUM DIFFERENTIATION DEGREE IN ENDOMETRIAL CANCER OF INTERMEDIATE RISK
The endometrial cancer (EC) of intermediate risk includes IAG3 and IBG1—2 endometrioid carcinoma, that is, tumors with differentiation of different degrees and of the invasion into the myometrium different depths. However, the principles and methods of their management are similar. Given the difference, it is advisable to check whether IAG3 and IBG1—2 EC differ for their prognosis.
Materials and methods. A retrospective study was carried out basing on the results of treating 918 patients with EC of intermediate risk for 2006—2010. The data of women were obtained from the Belarus Cancer-Registry, the disease sub-stages, the tumor histological types, the differentiation degrees, the operation volumes, the treatment regimens, the radiotherapy volumes and types, the patients future, the start and end dates of treatment were ascertained in the outpatient cards. The EC stages and substages were aligned with the TNM Classification and FIGO 2009. The number of patients with the IAG3 stage lacking invasion into the myometrium was 55, of those with the IAG3 stage the tumor invaded into the myometrium for up to 50% — 315, with IBG1 stage — 174, and with IBG2 stage — 374 women. The main methods of treatment were the following: combined treatment (CT) — 604 patients, treatment combined with chemotherapy (CT+ChT) — 253 women, surgical treatment (ST) — 31 subjects, radiotherapy as an independent method of treatment — 30 patients.
Results. In the IAG3 stage the tumor lacking invasion into the myometrium, the 5-year overall survival (OS) was 79.7±5.5%, the cancer-specific survival (CSS) — 86.6±4.7%, the recurrence-free survival (RFS) — 84.6±5.0%. In case of the IAG3 stage accompanied by invasion into the myometrium, OS was 75.6±2.4%, CSS — 81.3±2.2%, RFS — 78.0±2.4%. In the case of the IBG1 stage, OS was 84.5±2.8, CSS — 92.4±2.1%, RFS — 90.9±2.2%. In the IBG2 stage, OS was 83.3±2.0%, CSS — 90.5±1.6%, RFS — 87.2±1.8%. The recurrence rate for the IAG3 stage without invasion into the myometrium was 5.5%, for the IAG3 stage with the myometrium invasion — 14.9%, for the IBG1 stage — 4.6%, and for the IBG2 stage — 10.4%, respectively. Thus, in the intermediate risk group, the tumor differentiation degree is the main prognostic factor, and the depth of invasion into the myometrium is less significant.
Conclusion. The IAG3 stage is the most unfavorable form of EC of the intermediate risk. Further research is needed to determine the group of which risk it should be attributed to.