Endoscopic Characteristics of Colonic Tumours (C-LST)

A Correlation of the Endoscopic Characteristics of Colonic LSTs With Their Somatic or Germline Mutations. A Prospective, Genome Wide Study

The purpose is to investigate whether polyps that look different at colonoscopy, have formed via different mutations and have different risks of turning into cancer.

Laterally spreading tumours (LSTs), are polyps that have a lateral extension along the colon wall with minimal vertical growth. It has become evident over the last few years that rather than being a single entity requiring an accumulation of mutations, colon cancer is in fact a heterogenous disease forming via multiple distinct genetic pathways. Additionally, with improved endoscopic characterization, it has been noted from experience at Westmead hospital that two macroscopically distinct types of LSTs, "granular" and "non granular", have different natural histories and risks of invasive cancer. It is therefore hypothesised that different polyp types have different genetic abnormalities, and potentially form via distinct genetic pathways, although this theory has not been widely examined. This knowledge would be important in furthering our understanding of the development of cancer. There is accumulating evidence that genetic abnormalities may be a better predictor of cancer behaviour than histological grade. Additionally, guidelines for colonoscopy surveillance are currently a one size fits all approach that do not reflect the genetic heterogeneity of the disease and the knowledge that only 5% of polyps progress to cancer. Genetic studies may assess future cancer risk to a person in polyps once removed and plan surveillance colonoscopy frequency. This is an area with interest currently due to the national bowel cancer screening programme, with obvious cost implications for decision makers.

Patients who consent to participate in this study will have a small sample of their polyp and normal tissue sent for molecular testing.

A small sample of the colonic polyp will be obtained for molecular testing. The remaining polyp will be sent for regular histological testing

The aim of this project is to look for statistically significant differences in molecular abnormalities from the three known genetic pathways, between the two different morphological types, granular and non-granular, to potentially demonstrate that these different polyps form via different genetic pathways.

Inclusion Criteria: Intention to perform Endoscopic Mucosal Resection Polyp equal to or greater than 20mm over 18 years of age Able to give informed consent to involvement in trial Exclusion Criteria: Pregnancy Lactation: currently breastfeeding Taken clopidogrel within 7 days Taken warfarin within 5 days Had full therapeutic dose unfractionated heparin within 6 hours Had full therapeutic dose low molecular weight heparin (LMWH) within 12 hours Known clotting disorder