Endometrial Cancer Staging
Endometrial cancer staging in postmenopausal women with abnormal vaginal bleeding or pelvic pain requires surgical staging using the FIGO 2009 system, which emphasizes complete surgicopathologic assessment including depth of myometrial invasion, cervical stromal involvement, and lymph node status. 1
Initial Diagnostic Workup
Preoperative evaluation must include:
- Office endometrial biopsy (diagnostic in 90% of cases, though has a 10% false-negative rate requiring fractional dilation and curettage if symptoms persist) 2
- Complete blood count, liver and renal function tests 2
- Chest X-ray 2, 1
- Contrast-enhanced dynamic MRI if cervical involvement is suspected (this is the best imaging tool for assessing cervical invasion) 2, 1
- CT or MRI reserved for evaluating extrauterine disease when indicated by clinical symptoms, physical findings, or abnormal laboratory results 2
- Serum CA-125 may help monitor clinical response in patients with extrauterine disease, though it has limitations (falsely elevated with peritoneal inflammation/infection, normal with isolated vaginal metastases) 2
FIGO 2009 Surgical Staging System
The current standard is the FIGO 2009 staging system, which replaced clinical staging in 1988 because clinical staging was inaccurate in 15-20% of patients. 2, 1
Stage Definitions:
- Stage IA: No myometrial invasion or invasion to less than half of the myometrium 1
- Stage IB: Invasion equal to or more than half of the myometrium 1
- Stage II: Tumor invasion of cervical stroma but does not extend beyond the uterus 1
- Stage IIIA: Tumor invasion of the serosa of the corpus uteri and/or adnexae 1
- Stage IIIB: Vaginal and/or parametrial involvement 1
- Stage IIIC1: Positive pelvic lymph nodes 1
- Stage IIIC2: Positive para-aortic lymph nodes with or without pelvic nodes 1
Required Surgical Staging Components
Complete surgical staging includes:
- Total hysterectomy with bilateral salpingo-oophorectomy 1
- Assessment of depth of myometrial invasion (ratio of invasion to total myometrial thickness) 2
- Evaluation of cervical stromal or glandular involvement 2
- Documentation of tumor size and location (fundus vs. lower uterine segment/cervix) 2
- Histologic subtype with grade 2
- Assessment of lymphovascular space invasion 2
- Peritoneal cytology 2
- Evaluation of fallopian tubes and ovaries 2
- Systematic pelvic and para-aortic lymphadenectomy (though sentinel lymph node mapping is an acceptable alternative with 97.2% sensitivity and 99.6% negative predictive value when using indocyanine green) 1
Pathologic Assessment Requirements
The pathology review must document:
- Ratio of depth of myometrial/stromal invasion to myometrial thickness 2
- Cervical stromal or glandular involvement 2
- Tumor size 2
- Tumor location 2
- Histologic subtype with grade 2
- Lymphovascular space invasion 2
- Level of nodal involvement (pelvic, common iliac, para-aortic) 2
- Consideration of mismatch repair analysis to identify genetic problems 2
Clinical Context and Prognostic Significance
Approximately 75% of patients present with Stage I disease due to early symptoms (90% present with abnormal vaginal bleeding), resulting in a 5-year survival rate of 90% for Stage I patients. 2, 3
The stage of disease is the most significant prognostic marker, though other factors contribute including age, histology, grade, myometrial invasion, lymphovascular space invasion, tumor size, and hormone receptor status. 4
Critical Pitfalls to Avoid
- Never rely on a negative office endometrial biopsy in a symptomatic patient – the 10% false-negative rate mandates fractional dilation and curettage under anesthesia if symptoms persist 2
- Clinical staging alone is inadequate – it understages disease in 15-20% of patients, which is why surgical staging became the standard 2
- Do not perform routine systematic lymphadenectomy in all Stage I patients – while it provides prognostic information, randomized trials showed no improvement in disease-free or overall survival for routine lymphadenectomy in Stage I disease; sentinel lymph node mapping is an acceptable alternative 1