According to FIGO (The International Federation of Gynecology and Obstetrics), staging is clinical and is based on gynecological examination, cystoscopy, proctoscopy, IVP (iv pyelography) and chest X-ray.
Additional imaging with CT scan, MRI and/or PET scan is not included in the stage determination, but is often performed to help guide treatment. In the case of microinvasive cancer, staging is based on histological findings.
In cases where a hysterectomy was performed without knowing cervical cancer was present preoperatively, the disease should be classified as cervical cancer without staging.
Staging according to FIGO
Stage I: Tumor confined to the cervix (extension to uterus should be disregarded)
- Stage Ia: Tumor only detectable by microscopy with deepest invasion ≤ 5 mm and greatest extension ≤ 7 mm*
- Stage Ia1: Invasion depth ≤ 3 mm, horizontal spread ≤ 7 mm
- Stage Ia2: Invasion depth > 3 mm, but not > 5 mm, horizontal spread not>7 mm
- Stage Ib: Tumor macroscopically visible or preclinical cancers > Ia**
- Stage Ib1: Clinically visible lesion. Largest tumor diameter ≤ 4 cm
- Stage Ib2: Clinically visible lesion. Largest tumor diameter > 4 cm
Stage II: Tumor invades beyond cervix, but does not reach the pelvic wall or lower third of vagina.
- Stage IIa: Without parametrial invasion
- Stage IIa1: Clinically visible lesion ≤ 4 cm in largest diameter
- Stage IIa2:Clinically visible lesion > 4 cm in largest diameter
- Stage IIb: Obvious parametrial invasion.
Stage III: Tumor extends to pelvic wall and/or involves the lower third of the vagina and/or causes hydronephrosis or non-functioning kidney***
- Stage IIIa: Tumor involves lower third of vagina, but no extension to pelvic wall
- Stage IIIb: Tumor extends to pelvic wall and/or hydronephrosis or non-functioning kidney
Stage IV: Tumor extends beyond true pelvis (verified by histology), or involves rectum and bladder mucosa. The presence of bullous edema is not sufficient evidence to classify a tumor as stage IV.
- Stage IVa: Tumor invades neighboring organs
- Stage IVb: Distant metastasis
*The invasion is limited to a measured stromal invasion with a maximum depth of 5 mm and a horizontal spread not > 7 mm. Infiltration depth should not be > 5 mm calculated from the base of the epithelium of the surface, or gland. Depth of invasion should always be reported in mm, even in cases of "early (minimal) stromal invasion" (- 1 mm). Involvement of vascular or lymphatic vessels should not change the stage determination.
**All clinically visible lesions, even those with superficial invasion belong to stage Ib.
*** A tumor-free area is not found between the tumor and pelvic wall by rectal palpation. All cases with hydronephrosis or non-functioning kidney are included if no other cause for hydronephrosis can be found.