The FIGO staging system for cervical cancer, developed by the International Federation of Gynecology and Obstetrics (FIGO), is a global classification method. It provides a common language for medical professionals to categorize cancer based on its size, location, and spread to nearby tissues or distant organs.
Why Cancer Staging Matters
Cancer staging is a foundational step in cancer diagnosis and management. It provides a detailed picture of the disease’s progression, helping doctors estimate its likely behavior and anticipate challenges.
Staging guides treatment selection, tailoring interventions to patient needs. It also facilitates comparing treatment outcomes across studies and institutions, and provides a basis for discussing prognosis with patients and their families.
The FIGO Staging System for Cervical Cancer
The FIGO staging system for cervical cancer, updated in 2018, categorizes the disease into four main stages with specific substages that detail the tumor’s size, local spread, and distant metastasis.
Stage I indicates cancer confined to the cervix. Stage IA involves microscopic lesions diagnosable through histopathological examination of a surgical specimen. Stage IA1 refers to invasive carcinoma with stromal invasion of 3 mm or less and horizontal spread of 7 mm or less. Stage IA2 denotes invasive carcinoma with stromal invasion greater than 3 mm but not exceeding 5 mm, also with horizontal spread of 7 mm or less.
Stage IB cancer is still confined to the cervix but is clinically visible or larger than Stage IA lesions. Stage IB1 describes tumors clinically visible but 2 cm or less. Stage IB2 includes tumors greater than 2 cm but not exceeding 4 cm. Stage IB3 encompasses tumors greater than 4 cm.
Stage II indicates that the cancer has extended beyond the uterus but has not yet spread to the lower one-third of the vagina or pelvic sidewall. Stage IIA means no parametrial invasion, with Stage IIA1 referring to lesions 4 cm or less, and Stage IIA2 for lesions greater than 4 cm. Stage IIB signifies parametrial invasion, meaning the cancer has spread to the tissues surrounding the uterus.
Stage III signifies more extensive local or regional spread. Stage IIIA indicates that the cancer has spread to the lower one-third of the vagina but has not extended to the pelvic sidewall. Stage IIIB means the cancer has spread to the pelvic sidewall and/or caused hydronephrosis (swelling of the kidney due to urine backup) or a non-functioning kidney. Stage IIIC denotes pelvic and/or para-aortic lymph node metastasis, regardless of tumor size or local spread. Stage IIIC1 refers to pelvic lymph node involvement, while Stage IIIC2 indicates para-aortic lymph node involvement.
Stage IV represents the most advanced disease. Stage IVA means the cancer has spread to adjacent organs, such as the bladder or rectum, which is confirmed by biopsy. Stage IVB indicates that the cancer has spread to distant organs beyond the true pelvis, such as the lungs or liver.
How Staging is Determined
Determining the FIGO stage for cervical cancer involves diagnostic methods and procedures. A thorough clinical examination, including a physical pelvic exam, is performed. Imaging techniques like Magnetic Resonance Imaging (MRI) assess tumor size and local spread, particularly to the parametrial tissues.
Computed Tomography (CT) scans and Positron Emission Tomography (PET) scans help identify spread to lymph nodes or distant organs. Biopsies of suspicious areas are taken for pathological examination to confirm cancer and determine its characteristics. The 2018 FIGO staging system allows for the incorporation of imaging and pathology findings to assign the stage.
Impact on Treatment and Prognosis
The assigned FIGO stage directly influences treatment and prognosis. For early-stage cervical cancer (Stage I), treatment often involves surgical interventions like conization, hysterectomy, or radical hysterectomy, sometimes with lymph node dissection. Prognosis for these stages is generally more favorable, with higher long-term survival rates.
As cancer progresses to more advanced stages, treatment becomes more aggressive and systemic. For locally advanced stages (II and III), chemoradiation therapy, which combines radiation with chemotherapy, is a common treatment. Treatment choice is personalized, considering substage, tumor characteristics, and patient health. For Stage IV, treatment focuses on controlling disease spread and managing symptoms, often with systemic therapies like chemotherapy, targeted therapy, or immunotherapy, and palliative care.