What is the recommended system for classifying cervical cancer?

Cervical Cancer Classification System

The International Federation of Gynecology and Obstetrics (FIGO) staging system is the standard and most widely used classification system for cervical cancer, with the most recent 2018 update incorporating imaging findings and pathological assessment to guide treatment decisions. 1

Current FIGO Staging System Overview

• The FIGO staging system has been revised in 2018 to incorporate imaging findings and pathological assessment in addition to clinical examination, providing more accurate staging and treatment guidance 1, 2
• The staging system now includes assessment of retroperitoneal lymph nodes: stage IIIC1 for pelvic lymph node involvement and IIIC2 for para-aortic node involvement 2
• Stage IB has been divided into three subgroups based on tumor size: IB1 (<2 cm), IB2 (2-4 cm), and IB3 (>4 cm) 2, 3
• The revised system allows for cross-sectional imaging (MRI, CT, PET/CT) to be used for staging, which has led to significant stage migration in many patients 3, 4

Diagnostic Methods for Staging

• Clinical examination remains fundamental for initial staging according to FIGO guidelines 1
• MRI is superior to CT for tumor extension assessment and is preferred for pelvic and abdominal imaging due to its excellent soft tissue contrast 1, 5, 6
• Routine staging workup includes:
  • Clinical gynecological examination 1
  • Blood counts and routine chemistry including renal and liver function tests 1
  • Chest radiograph, CT, or combined PET/CT 1
  • MRI as indicated for detailed assessment of tumor size and parametrial involvement 4
• PET/CT is particularly valuable for nodal assessment and detection of distant metastases 5, 4
• SCC antigen may be useful for follow-up in squamous cell carcinomas if initially elevated 1

FIGO Staging Classification Details

• Stage 0: Carcinoma in situ (preinvasive carcinoma) 1
• Stage I: Cervical carcinoma confined to the uterus 1
  • Stage IA: Invasive carcinoma diagnosed only by microscopy with maximum depth of invasion <5.0 mm 1
    • Stage IA1: Measured stromal invasion ≤3.0 mm in depth and ≤7.0 mm in horizontal spread 1
    • Stage IA2: Measured stromal invasion >3.0 mm and ≤5.0 mm with horizontal spread ≤7.0 mm 1
  • Stage IB: Clinically visible lesion or microscopic lesion >IA2 1
    • Stage IB1: Tumors <2 cm in greatest dimension 2, 3
    • Stage IB2: Tumors 2-4 cm in greatest dimension 2, 3
    • Stage IB3: Tumors >4 cm in greatest dimension 2, 3
• Stage II: Tumor extends beyond the uterus but not to pelvic wall or lower third of vagina 1
  • Stage IIA: Without parametrial invasion 1
    • Stage IIA1: Clinically visible lesion ≤4.0 cm 1
    • Stage IIA2: Clinically visible lesion >4.0 cm 1
  • Stage IIB: With parametrial invasion 1
• 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, no extension to pelvic wall 1
  • Stage IIIB: Tumor extends to pelvic wall and/or causes hydronephrosis or non-functioning kidney 1
  • Stage IIIC: Involvement of pelvic and/or para-aortic lymph nodes 2
    • Stage IIIC1: Pelvic lymph node metastasis only 2
    • Stage IIIC2: Para-aortic lymph node metastasis 2
• Stage IV: Tumor extends beyond the true pelvis or involves bladder or rectal mucosa 1
  • Stage IVA: Spread to adjacent organs 1
  • Stage IVB: Spread to distant organs 1

Histopathological Classification

• The NCCN Guidelines discuss squamous cell carcinoma, adenosquamous carcinoma, and adenocarcinoma of the cervix 1
• Neuroendocrine carcinomas, small cell tumors, glassy-cell carcinomas, and sarcomas require specialized management approaches 1
• Histopathological assessment is crucial for accurate staging, particularly in early-stage disease 7
• The College of American Pathologists (CAP) protocol for cervical carcinoma provides a useful guide for pathological assessment 1

Clinical Implications and Pitfalls

• The method used to assign a stage should be recorded and reported to ensure consistency 2
• Stage migration is common when comparing the 2018 FIGO system to previous versions, with up to 59% of patients being upstaged in some studies 3
• Accurate staging is essential as it directly impacts treatment options and prognosis 2, 4
• Common pitfalls in staging include:
  • Underestimation of tumor size without proper imaging 4
  • Failure to detect parametrial involvement 6
  • Missed lymph node metastases without appropriate imaging techniques 4
  • Inconsistent methods for measuring tumor dimensions 7

Importance of Multidisciplinary Approach

• A multidisciplinary treatment planning approach is mandatory, based on tumor size and extension 1
• The team should include gynecologic oncologists, radiation oncologists, radiologists, and pathologists 5
• Treatment decisions should be based on accurate staging to optimize outcomes related to morbidity, mortality, and quality of life 5