Cervical cancer is the 4th most common cancer in women worldwide, according to the World Health Organization. It is also a leading cause of cancer-related deaths, especially for women in low-income countries. Almost all cases can be linked to a human papilloma virus (HPV) infection.
The disease is staged in accordance with the International Federation of Gynecology and Obstetrics (FIGO) system, said researcher Kari Wagner-Larsen, MD, a radiologist at Haukeland University Hospital in Bergen, Norway, during her Wednesday session.
"Prior to 2018, this staging was primarily based on clinical examination," Dr. Wagner-Larsen said.
In 2018, FIGO was revised to incorporate information from imaging and pathological assessments into the stage assignments.
"With pelvic MRI now being performed during the diagnostic work-up of patients with cervical cancer, it plays an essential role in evaluating the local and regional extent of the disease," Dr. Wagner-Larsen said.
The central parameters defining the stages listed in the FIGO 2018 system can accurately be assessed by MRI, she said.
"The FIGO stage is directly related to prognosis and guides the stratification of patients to different treatments," she said. "As a result, good interobserver reproducibility between radiologists is absolutely crucial as reported imaging findings will have a direct impact on both therapeutic strategy and patient outcome."
Evaluating MRI Staging
Dr. Wagner-Larsen presented the results of a recent study she led that assessed interobserver agreement for central MRI-based FIGO staging parameters at primary diagnostic workup in patients with cervical cancer.
"Our work also evaluated the potential value of the MRI-derived staging parameters for predicting aggressive disease, which is relevant for developing risk-stratified treatment strategies," she added.
The study included 417 patients diagnosed with uterine cervical cancer between 2002 and 2017 and who had a pre-treatment pelvic MRI. All MRI examinations were retrospectively and independently read by three radiologists blinded for clinical information. A consensus reading was generated using the majority reading as all variables were categorical.
MRI-derived parameters relevant to the FIGO 2018 system were recorded, including maximum tumor diameter (≤2 cm/>2 cm and ≤4 cm/>4 cm), parametrial invasion, vaginal invasion, metastatic lymph nodes, and bladder and/or rectum invasion.
MRI Paramount at Primary Diagnostic Work-Up
The study found that interobserver agreement for most MRI-staging parameters was good (overall κ values of 0.61-0.78 for tumor size in three categories (≤2/>2 and ≤4/>4 cm), parametrial- and vaginal tumor invasion and lymph node metastases).
"This finding supports the use of MRI for pre-therapeutic staging and tailoring treatment in uterine cervical cancer," said Dr. Wagner-Larsen. Dr. Wagner-Larsen also noted that the imaging parameters included in the FIGO 2018 system were associated with significantly reduced disease-specific survival. However, in a multivariable model that included the same imaging variables, only MRI-assessed large tumor size and bladder-/rectum invasion were independent predictors of poor outcome.
"Pelvic MRI is paramount at primary diagnostic work-up in uterine cervical cancer," Dr. Wagner-Larson said. "This study demonstrates good interobserver reproducibility for core MRI staging parameters, supporting the validity of MRI as a diagnostic tool guiding therapeutic strategy and prognostication."
Dr. Wagner-Larson said the potential added role of advanced and functional MRI techniques and radiomic tumor profiling in addition to staging parameters needs to be addressed in future studies.
For More Information:
View the RSNA 2020 session Good Interobserver Agreement for MRI-based 2018 FIGO Staging Parameters in Uterine Cervical Cancer — SSGU05 at RSNA2020.RSNA.org.
