Invasive pit pattern, macronodule and depression are predictive factors of submucosal invasion in colorectal laterally spreading tumours from a Western population

Abstract

Background: Laterally spreading tumours are separated in subclasses: granular, homogenous or nodular mixed; and non-granular, flat or pseudodepressed. For every subtype, a proper risk of submucosal invasive cancer has been described in Asian series.

Objective: The aim of the study was to determine the rate of cancer and submucosal invasive cancer in a Western series of endoscopic-resected laterally spreading tumours and their endoscopic predictive factors.

Methods: A total of 374 laterally spreading tumours ≥20 mm were resected by endoscopy in our single centre between 2012-2016. We analysed endoscopic and pathological data from our prospective database, determining the rates of cancer and submucosal invasive cancer according to the subtype of laterally spreading tumour.

Results: The rates of submucosal invasive cancer for granular homogenous, granular nodular mixed, non-granular flat, non-granular pseudodepressed laterally spreading tumours were 4.9%, 15.9%, 3.0% and 19.4%, respectively. Endoscopic mucosal resection was used in 58.0% and endoscopic submucosal dissection in 42.0%. Endoscopic submucosal dissection was associated with a higher rate of en-bloc resection (87.3% vs 26.3%; p < 0.0001), and a lower risk of recurrence (7.6% vs 15.2%; p = 0.026). Adverse event rates were not statistically different (9.5% vs 6.4%, p = 0.26). Predictive endoscopic factors of submucosal invasive cancer were: invasive pit pattern (hazard ratio = 33 (8.81-143.3)), non-granular pseudodepressed laterally spreading tumours (hazard ratio = 11.9 (0.89-146.2)), and granular nodular mixed laterally spreading tumours (hazard ratio = 3.42 (0.99-13.0)).

Conclusions: The risk of submucosal invasive cancer varies according to the laterally spreading tumour subtype. Three factors were associated with submucosal invasion and should justify an endoscopic submucosal dissection: non-granular pseudodepressed laterally spreading tumours, granular nodular mixed laterally spreading tumours subtypes and invasive pit pattern.

Keywords: Laterally spreading tumour; endoscopic mucosal resection; endoscopic submucosal dissection; invasive cancer.

Figure 1.

(a) Endoscopic image of granular homogenous laterally spreading tumour (LST-G-H) with white light; (b) granular nodular mixed laterally spreading tumour (LST-G-N) with white light; (c) non-granular flat laterally spreading tumour (LST-NG-F) with white light; (d) image of non-granular pseudodepressed laterally spreading tumour (LST-NG-PD) with blue light imaging (BLI).

Figure 2.

Flow chart of the laterally spreading tumours (LSTs) of the study.