The Italian Society of Digestive Endoscopy (SIED) and the Italian Association of Gastroenterologists and Hospital Digestive Endoscopists (AIGO) want to develop an effective training program for endoscopists to improve the quality of colonoscopies through careful evaluation of quality indicators and how they can be improved with an appropriate educational program. Primary objective of this study is to evaluate the variation of "Polyp Detection Rate (PDR) and Adenoma Detection Rate (ADR)" obtained by operators at high and low volume of colonoscopy before and after a training period. Secondary objectives are to compare high and low volume endoscopists' performance before and after training comparing by evaluation of withdrawal time; Number polyps / patient and Number adenomas / patient; the percentage and time of intubation of the cecum, ; patient's pain perception based on the Nurse Assessed Patient Comfort Score (NAPCOMS) scale. The study is structured as follow:

• A first phase when all endoscopists collect the results of 200 colonoscopies in an electronic Case Report Form (eCRF) is formed(maximum enrollment period 4 months).
• A second phase of training through an e-platform in which the endoscopists are offered with an online refresh reviewing the international standard parameters to perform a quality colonoscopy. Once the final training exam have been passed, the endoscopist will be able to access the third phase
• A third phase in which the endoscopists will collect prospectively the colonoscopies they perform in an eCRF (maximum enrollment period 4 months).

Inclusion Criteria:

• patients between 50 and 75 years old
• colonoscopy for cancer screening program, post polypectomy follow up, patients with abdominal symptoms suggestive for colonic pathology.

Exclusion Criteria:

• patients aged < 50 or > 75 yrs

  • presence of alarm symptoms
  • American Society of Anesthesiologists (ASA) Classification ≥ 3
  • presence of colonic stenosis
  • previous colonic resection
  • Presence of diverticulitis
  • history of Inflammatory Bowel Disease (IBD)
  • History of polyposis syndrome
  • Pregnancy or breastfeeding
  • inability to provide informed consent
  • Severe cardiovascular illness
  • contraindication to undergo to sedation
  • Anticoagulant therapy
  • Melanosis coli

Patient aged between 50 and 75 years old who present with abdominal symptoms suggestive for colonic patholgy or included in cancer screening program