New research demonstrates significant decreases in major-stage and substage concordance between pelvic MRI and pathology results with the 2023 International Federation of Gynecology and Obstetrics (FIGO) staging system in comparison to the 2009 version.
For the retrospective study, recently published in Radiology, researchers compared the two versions of the FIGO system through a review of preoperative abdominal MRI and molecular data for 231 women (median age of 63) who had biopsy-confirmed endometrial cancer. The study authors noted a 7.8 percent recurrence rate and a 7 percent mortality rate in the cohort.
The researchers found that major stage concordance between pelvic MRI and pathology findings for the 2009 FIGO staging system was 86.6 percent in contrast to 76.2 percent for the 2023 version of the FIGO system.
There was also a greater than 17 percent decline in substage concordance between the 2009 and 2023 FIGO staging systems (74 percent vs. 56.3 percent), according to the study authors.
“ … The 2023 International Federation of Gynecology and Obstetrics (FIGO) update reduced substage concordance between preoperative pelvic MRI and final pathologic examination, primarily due to the missed detection of minimal myometrial invasion (MI) and micrometastatic lymph node involvement,” noted lead study author Giacomo Avesani, MD, PhD, who is affiliated with the Department of Diagnostic Imaging and Oncologic Radiotherapy at Agostino Gemelli University in Rome, Italy, and colleagues.
Three Key Takeaways
• MRI-pathology concordance drops notably under FIGO 2023. Major stage agreement fell from 86.6 percent (FIGO 2009) to 76.2 percent (FIGO 2023), and substage agreement dropped even more sharply, from 74 percent to 56.3 percent. This is driven mainly by MRI's difficulty in detecting minimal myometrial invasion and micrometastatic nodal disease, findings that are often subtle or below MRI's resolution threshold.
• MRI should be treated as one input, not the final word, on staging. Discordances weren't purely an MRI detection problem. A meaningful share (roughly 19 percent) stemmed from histologic/grading changes between biopsy and final pathology, and about 12 percent from histology-dependent factors like lymphovascular space invasion that imaging can't assess. The study authors frame FIGO 2023 as requiring an integrated anatomo-molecular workup (MRI + biopsy histology + molecular testing) rather than MRI alone.
• Despite lower MRI/pathology concordance, prognostic value is preserved. Both FIGO 2009 and 2023 systems still successfully stratified patients by disease-free and overall survival, and molecular data reclassified about 6 percent of patients. So while radiologic-pathologic staging agreement is weaker under the new system, its clinical utility for risk stratification remains intact.
The study authors pointed out that myometrial invasion occurred in 36.6 percent of patients with discordant findings and nodal involvement was a factor in 17.8 percent of those with discordance between pelvic MRI and pathology results.
However, the researchers also found that 18.8 percent of discrepancies were due to histologic and grading changes between pre-op biopsy and final surgical pathologic examination, and 11.9 percent were related to histology-dependent factors such as lymphovascular space invasion (LVSI). Molecular data, which was incorporated into the FIGO 2023 system, facilitated reclassification of patients in six percent of the cohort, according to the study authors.
The researchers also determined that the 2009 and 2023 FIGO systems both provided successful stratification of patients for disease-free survival and overall survival.
“For radiologists, FIGO 2023 therefore reinforces the need to interpret MRI not as a standalone proxy of the final stage, but as the anatomic pillar of an integrated anatomo-molecular risk assessment built on biopsy histologic examination and molecular testing,” posited Avesani and colleagues.
