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Understanding Borderline Endocervical Reports in UK Cervical Screening webinar report

Date: 15 May 2025

Presenter: Helen Burrell, Director, Southwest Cytology Training School

Hosted by: British Association for Cytopathology (BAC)

Introduction

The British Association for Cytopathology (BAC) recently hosted a webinar focused on the interpretation and use of the “borderline endocervical cells” category in the UK cervical screening programme. This area remains complex due to its rarity and variability across laboratories. Helen Burrell presented findings from a national questionnaire circulated to UK cervical screening laboratories.

Why Focus on Borderline Endocervicals?

This diagnostic category—though not new—has gained renewed attention since being separated out from Borderline squamous changes for individual reporting. Accurate use is critical: while some cases result in significant pathology such as CGIN (cervical glandular intraepithelial neoplasia) or even cancer, others prove benign. Given this balance, it's essential not to overuse the category and subject patients to unnecessary investigations.

Objectives of the Survey

The BAC survey aimed to understand:

  • How consistently labs use the borderline endocervical category
  • The frequency of associated CIN2+ outcomes (cervical intraepithelial neoplasia grade 2 or worse)
  • Reporting practices and use of consensus or MDT (multidisciplinary team) review

Survey Methodology

Questionnaires were sent to all UK cervical screening laboratories. Nine labs responded, submitting data for two separate years. The data covered:

  • Workload volumes
  • Reporting rates of borderline endocervicals
  • Histological outcomes
  • Practices around consensus reporting and MDT discussion

 

Key Findings

1. Borderline Endocervical Reporting Rates

Reporting rates varied between 0.01% and 0.05% of total screening workload. One lab reported a substantial reduction in usage across the two years—more than halving the number of cases—potentially due to internal audit or staffing changes.

2. Histological Outcomes

From 1,367 borderline endocervical cases:

33% resulted in a CIN2+ diagnosis

17% resulted in CGIN or glandular abnormality

~30% had no significant histological abnormality

13% had no biopsy or treatment

This aligns with literature, where CIN2+ outcomes vary widely between studies.

3. Variability Across Labs

CIN2+ outcome rates for borderline endocervicals ranged from 16% to 59% between labs. This raises questions:

Are some labs overusing the category, leading to unnecessary treatment?

Are others underdiagnosing or miscategorising potentially high-grade disease?

4. Nature of Diagnosed Pathology

Interestingly, many cases diagnosed as borderline endocervicals had squamous outcomes upon histology rather than glandular abnormalities, suggesting possible misinterpretation of immature squamous or metaplastic cells.

Audit and Quality Assurance

Consensus Reporting

Only 7 of the 9 labs reported using consensus reporting for all borderline endocervical cases. However, no clear trend showed that consensus reporting improved CIN2+ detection or specificity. Useful link to BAC Code of Practice.

MDT Discussion

Most labs were unsure how many cases were discussed at MDT. While guidance states that normal colposcopy following a borderline endocervical report should prompt MDT discussion, this practice is not routinely audited.

Recommendations and Future Considerations

Helen Burrell raised several points for improvement:

Clearer Diagnostic Criteria

Current NHSCSP guidelines lack detail. Unlike CGIN, where nuclear and architectural criteria are established, borderline endocervical interpretation remains subjective.

Training and Case Sharing

Many false-positive cases result from benign conditions like cervicitis, polyps, or tubal metaplasia. Increasing exposure to these examples during training may reduce overuse.

Standardised Benchmarks

Establishing acceptable ranges for borderline endocervical reporting and CIN2+ outcomes would aid internal audits and support consistency.

Digital Case Library

A central collection of example slides—especially negative cases—could help standardise reporting nationally, particularly as digital pathology becomes more widespread.

Conclusion

The data highlighted substantial variability in the use and outcomes of borderline endocervical reports across UK labs. This inconsistency suggests a need for clearer guidance, targeted training, and greater cross-laboratory collaboration to ensure accurate and consistent use of this important diagnostic category.

Final Thoughts

This presentation has prompted important discussions about diagnostic thresholds and patient safety. While borderline endocervicals are rare, their correct identification—and non-identification—has significant consequences for clinical management. Continued efforts to refine training, audit practices, and national standards are essential.

Labs involved in the audit will be contacted individually to confirm their anonymised identifier.