Central Pathology Review Finds Discordance In LNG IUD Trial

Key Takeaways:

• Interobserver agreement was reported at baseline and at both post-treatment timepoints.
• Discordance was reported more often in site-labeled hyperplasia than adenocarcinoma, and discordant cases were frequently upgraded on central review.
• The authors emphasized the value of gynecologic pathology confirmation and comparison with the pretreatment biopsy when evaluating treated specimens.

Reported agreement was 73% at baseline, 80% at 3 months, and 77% at 6 months across serial reviews. The comparisons included pretreatment material and follow-up biopsies obtained after progestin exposure within the trial’s serial pathology assessments. In this series, complete alignment was not observed at any reported interval, indicating persistent variability across baseline assessment and both post-treatment timepoints.

Investigators reported discordance in 42% of site-reported endometrial hyperplasia diagnoses and 13% of site-reported endometrial adenocarcinoma diagnoses. The study situates this comparison in a setting where distinguishing hyperplasia from adenocarcinoma is recognized as a histopathologic challenge both before and after treatment. That framing places the discordance within routine classification of endometrial specimens rather than as an issue confined to a single review stage. The abstract also reports denominators for several key comparisons (e.g., agreement at baseline, 3 months, and 6 months), allowing the reported proportions to be read in the context of those sample sizes.

Among discordant cases, 77% (72/94) were upgraded to higher-risk pathology on central review. This directional finding describes changes within the discordant subset rather than how often site and central readings differed across the full series. The study further notes that postprogestin histology has been less frequently evaluated for interobserver variability than pretreatment endometrium in prior work. Within the trial’s follow-up assessments after levonorgestrel exposure, central review altered categorization for some treated specimens, with disagreements more often shifting toward higher-risk interpretations than toward less concerning categories.

The authors emphasized confirmation by a gynecologic pathologist and comparison of treated specimens with the pretreatment biopsy. They also describe central review as relevant to clinical trial reporting and to response assessment in progestin-treated endometrium. The interpretation remains observational and focuses on how serial specimens may be contextualized when treatment-related changes alter histologic appearance over time. In the authors’ view, side-by-side review with the pretreatment biopsy helps contextualize post-treatment histology during interpretation.