Tumor size: a better independent predictor of distant failure and death than depth of myometrial invasion in International Federation of Gynecology and Obstetrics stage I endometrioid endometrial cancer.

Objective: Depth of myometrial invasion is considered as the strongest predictor of distant failure and death from disease in stage I endometrial cancer. The aim of this study was to determine whether tumor size (TS) is an independent prognostic indicator of survival and a better predictor than depth (%) of myometrial invasion, in stage I endometrioid endometrial cancer.

Methods: This was a retrospective study of all women with International Federation of Gynecology and Obstetrics stage I endometrioid endometrial carcinoma from January 2000 to December 2007, who had surgery at the Northern Gynaecological Oncology Centre. Surgicopathological, follow-up, and survival data were collected. Tumor size (a continuous variable) was defined as the maximum tumor dimension. Univariate and multivariate analyses to predict distant recurrence and death from disease were performed comparing known risk factors. The prognostic accuracy of TS was then assessed by receiver operating characteristic curve analyses, and an optimum cutoff was proposed.

Results: A total of 216 women were identified. Pelvic lymphadenectomy was performed in 51 women (24%). The median follow-up time was 80 months (95% confidence interval [95% CI], 34-131 months), with 9 distant recurrences and 11 disease-related deaths. Tumor size was the only independent predictor of both distant recurrence (hazard ratio [HR], 1.05; 95% CI, 1.02-1.08; P = 0.004) and death from disease (HR, 1.03; 95% CI, 1.00-1.07; P = 0.05). Myometrial invasion only predicted distant failure (HR, 1.03, 95% CI, 1.00-1.05; P = 0.03). In women who did not have pelvic lymph node dissection (n = 165), only TS retained its independent prognostic value to predict both distant failure (HR, 1.08; 95% CI, 1.03-1.13; P = 0.002) and death from disease (HR, 1.05; 95% CI, 1.01-1.10; P = 0.02). In women who underwent pelvic lymphadenectomy, none of the variables predicted the above outcomes.

Conclusions: Tumor size could play a significant role in risk stratification and planning adjuvant treatment in women with International Federation of Gynecology and Obstetrics stage I endometrioid endometrial cancer.