Accurate size measurement of colorectal polyps is important for planning polyp resection and post-polypectomy surveillance. This study evaluated a through-the-scope laser-based probe for polyp size measurement during colonoscopies.

A prospective pilot study was conducted at CHUM in which polyps in enrolled patients were attempted to be measured with a laser-based probe. The primary outcome was the accuracy of laser-based polyp measurements, assessed as mean bias using microscopic sizing as the reference. Secondary outcomes included agreement with the reference, technical success rate, reasons for failed measurement, and per-polyp measurement time.

Among 323 patients, laser-based measurement was attempted for 237 polyps; 149 had a microscopic size measurement. The technical success rate of the laser-based probe was 40.9% (97/237; 95% CI, 34.6%–47.5%), with mean time per measurement of 1:35. Accounting for specimens that could not be resected en bloc for microscopic measurements, a total of 41/149 (27.5%; 95% CI, 20.7%–35.5%) had paired laser-based and microscopy measurements for the primary analysis. Laser-based measurement demonstrated accurate sizing with minimal bias (–0.10 mm, 95% CI –0.30 to 0.10; P = 0.328) and met the 0.4 mm non-inferiority margin. Agreement with the reference was high (ICC = 0.91; 95% CI, 0.83–0.95), with near-perfect categorical concordance (kappa = 0.85) and 95.1% accuracy (39/41; 95% CI, 82.2–99.2). Bland–Altman limits of agreement ranged from –1.34 mm to 1.14 mm.

 Laser-based measurement provided accurate polyp sizing when obtained. However, the technical success rate was limited by longer measurement times and device issues.