Residual myometrial invasion after intracavitary irradiation of endometrial adenocarcinoma stages I and II. Relations to DNA content and S-phase rate.

The DNA content and the S-phase rate were determined by flow cytometry in 129 women with endometrial adenocarcinoma in stages I and II. Aneuploidy and elevated S-phase rates were statistically correlated to loss of histopathologic differentiation. After preoperative intracavitary irradiation and surgery, the occurrence of residual myometrial invasion was studied. Residual myometrial invasion was found in 28 (22%) cases. In 17 (17%) of the peri-diploid (1.8c-2.2c) and in 11 (38%) of the aneuploid tumors, respectively, the myometrium was invaded (p less than 0.05). No statistical correlation was found between mean S-phase rate and myometrial invasion. The difference in residual myometrial invasion found between aneuploid and peri-diploid tumors after intracavitary treatment may reflect a primary difference in the tendency to invade the myometrium or a difference in responsiveness to radiotherapy.