Optical assessment of scars after EMR - STAR-LNPCP Trial

The STAR-LNPCP trial conducted a multicenter study to assess the reliability of optical assessment as a follow-up method for scars after piecemeal endoscopic mucosal resection (EMR) of large colorectal polyps (≥20 mm). The study aimed to determine whether routine biopsy is still necessary during the 6-month follow-up, especially in community hospital settings where evidence has been limited. Traditionally, follow-up included tattoo placement and routine biopsies to detect recurrence, but expert centers have suggested that careful optical assessment may suffice, potentially avoiding unnecessary biopsies.

### Key Details of the STAR-LNPCP Trial:

1. **Study Design**:

• Post-hoc analysis of the STAR-LNPCP trial.
• Conducted across 30 Dutch community hospitals between 2019 and 2022.
• Included 1277 scar assessments after piecemeal EMR.

2. **Scar Identification**:

• Scar identification was highly successful, achieved in 95% of cases (1215 out of 1277).
• Tattoo placement did not impact the ability to locate scars.

3. **Routine Biopsy**:

• Routine biopsies were performed in 86% of cases (1050 out of 1215 scars).
• Recurrence was detected in 19% of biopsied scars.

4. **Optical Assessment Findings**:

• Optical diagnosis showed a **negative predictive value (NPV)** of 98%, meaning if the scar appeared normal to the endoscopist, there was a 98% chance that no recurrence was present.
• Diagnostic accuracy was high at 93%, with a **Cohen's kappa** of 0.78, indicating substantial agreement between optical assessment and histological biopsy results.
• Positive predictive value was 74%, but false positives were more common when clips had been used during the initial procedure (11% vs. 5%).

5. **Performance of Dedicated Endoscopists**:

• Dedicated endoscopists performed better than non-specialized endoscopists:
• Higher scar identification rate (96% vs. 88%).
• Fewer missed recurrences.

6. **Implications**:

• The study supports that routine biopsies and tattoo placement can be safely omitted during follow-up when scars are evaluated by well-trained, dedicated endoscopists.
• Optical assessment alone is highly reliable for ruling out recurrence, simplifying follow-up and reducing unnecessary procedures.

### Conclusion:

The STAR-LNPCP trial demonstrated that optical assessment is a robust and effective method for follow-up of scars after piecemeal EMR of large colorectal polyps. With a high negative predictive value and diagnostic accuracy, routine biopsy may no longer be necessary, particularly when performed by skilled endoscopists. This approach can streamline follow-up in community hospital settings, reduce patient burden, and minimize unnecessary interventions.