What are the stages of cervical cancer?

Cervical Cancer Staging

FIGO Staging System Overview

Cervical cancer staging follows the International Federation of Gynecology and Obstetrics (FIGO) classification, which was revised in 2018 to incorporate imaging and pathological findings alongside clinical examination, significantly improving staging accuracy from 79% to over 90%. 1, 2

Stage Definitions

Stage 0 and Stage I (Confined to Cervix)

• Stage 0 (Tis): Carcinoma in situ (preinvasive carcinoma) 1
• Stage I: Tumor confined to the cervix 1

Stage IA (Microinvasive): Invasive carcinoma diagnosed only by microscopy with stromal invasion ≤5.0 mm depth and ≤7.0 mm horizontal spread 1

• IA1: Stromal invasion ≤3.0 mm depth and ≤7.0 mm horizontal spread 1
• IA2: Stromal invasion >3.0 mm but ≤5.0 mm depth with ≤7.0 mm horizontal spread 1

Stage IB: Clinically visible lesion confined to cervix or microscopic lesion greater than IA2 1

• IB1: Clinically visible lesion ≤4.0 cm in greatest dimension 1
• IB2: Clinically visible lesion >4.0 cm in greatest dimension 1

Stage II (Beyond Uterus, Not to Pelvic Wall)

• Stage II: Tumor invades beyond uterus but not to pelvic wall or lower third of vagina 1, 2

Stage IIA: Without parametrial invasion 1, 2

• IIA1: Clinically visible lesion ≤4.0 cm in greatest dimension 1, 2
• IIA2: Clinically visible lesion >4.0 cm in greatest dimension 1, 2

Stage IIB: With parametrial invasion 1, 2

Stage III (Extension to Pelvic Wall or Lower Vagina)

• Stage III: Tumor extends to pelvic wall and/or involves lower third of vagina and/or causes hydronephrosis or non-functioning kidney 1

Stage IIIA: Tumor involves lower third of vagina without extension to pelvic wall 1

Stage IIIB: Tumor extends to pelvic wall and/or causes hydronephrosis or non-functioning kidney 1

Stage IIIC (Added in 2018 revision): Lymph node involvement regardless of tumor size or extent 3

• IIIC1: Pelvic lymph node involvement only 3
• IIIC2: Para-aortic lymph node involvement 3

Stage IV (Distant Spread)

Stage IVA: Tumor invades bladder or rectal mucosa, or extends beyond true pelvis 1

Stage IVB: Distant metastasis (includes inguinal lymph nodes and intraperitoneal disease, excludes vaginal, pelvic serosa, and adnexal metastasis) 1

Critical Staging Principles

Key Considerations

• Extension to uterine corpus should be disregarded for staging purposes; only vaginal and parametrial extension determine stage 1, 2
• Lymphovascular space invasion (LVSI) does not affect stage classification but is an important prognostic factor that must be documented 1, 2
• Pathological assessment (designated "p") takes precedence over radiological findings (designated "r") when both are available 2, 3
• Bullous edema alone is not sufficient to classify as Stage IV; actual mucosal invasion must be present 1, 2

Imaging Integration

• MRI is the preferred imaging modality with 90.9% precision compared to 79% for clinical staging alone 2, 4
• PET has sensitivity of 53-73% for early-stage lymph node detection and 75% for para-aortic nodes in advanced stages 1, 4
• The 2018 FIGO revision allows incorporation of imaging findings to improve staging accuracy 2, 5

Common Pitfalls to Avoid

• Do not upstage based on uterine corpus extension, as this should be ignored per FIGO criteria 1, 2
• Do not confuse bullous edema with bladder/rectal invasion; only true mucosal involvement warrants Stage IVA 1, 2
• Do not alter stage based on LVSI presence, though it should be documented as a prognostic factor 1, 2
• When in doubt between two stages, assign the lower stage 3