Introduction/Background The distance between the deepest invasion of the myometrium and serosa can be an alternative method of measurement and a better predictor of prognosis in the case when the degree of invasion is more difficult to determine due to the presence of leiomyoma or adenomyosis. The distance between endometrial cancer (EC) and serosa may be useful in predicting lymphovascular invasion, histological grade, lymph node metastasis, adnexal involvement, and uterine cervical invasion. The aim of this study was to determine the correlation between tumor distance from serosa (TDS) and degree of myometrial invasion (MI) in EC measured by transvaginal sonography (TVS).

Methodology A prospective study was done amongst 60 women with histopathologically proven EC. All women were subjected to TVS measurement of TDS and degree of MI. All women are underwent total abdominal hysterectomy with bilateral adnexectomy for definitive histopathological diagnosis served as a reference method for assessment of TDS and MI.

Results The TDS in the group of patients with MI less than 50% was 1.15 (± 0.56) cm, from 0.31 to 2.6 cm. In the group with MI greater than 50% it was 1.04 (± 1.29) cm, from 0.1–7.0 cm. The difference in mean TDS was 0.11 cm between the two study groups and was statistically significant (Mann Whitney; Z = 2.05; p = 0.0394). In the total sample, the TDS was 1.1 (± 0.94) cm, from 0.1–7.0 cm.

Conclusion Our study showed a clear and significant correlation between TDS and the degree of MI obtained by TVS, which was also confirmed by the gold standard, histopathologically diagnosis of surgical material. This might be helpful in assessment of MI in case when it is aggravated due to the presence of leiomyoma and adenomyosis.