How do I pick the best doctor for my colonoscopy?

Choose an Advanced Endoscopist for your colonoscopy

Gastroenterologists (and some surgeons) undergo training in colonoscopy and gastroscopy during their specialist training.  This allows them to perform diagnostic colonoscopies and gastroscopies, and to remove small and medium sized polyps. 

The removal of very large polyps and early cancers of the gut, however, is a type of minimally-invasive surgery and requires a much higher level of expertise.  Generally this sort of training is sought overseas in large volume hospitals as New Zealand generally doesn’t have a large enough population of patients with these problems to allow development of sufficient expertise during training.  Because of the lengthened duration of training to become an Advanced Endoscopist, there are few of these specialists in New Zealand. 

Dr Cameron is an Advanced Endoscopist who has completed much of his training at the highest levels worldwide. Choosing an Advanced Endoscopist like Dr. Cameron offers added reassurance. With his extensive experience in managing the most difficult cases in central New Zealand, Dr. Cameron can efficiently identify and address any issues, often reducing the need for multiple colonoscopies. Additionally, he ensures that polyps are removed in the best manner to minimise the likelihood of complications or need for surgery.

Have you had a positive FIT screening test?

Broadly speaking, the calibration of the NZ national bowel screening stool test means that if you have positive test there is a one third chance there is nothing much to be found, a one third chance that there is a medium-sized polyp or two, and a one third chance that there is a large polyp or cancer.  Overall a positive test means there is a 10% chance of cancer.  Amongst the cancers, some will be polyp cancers which means they might be curable by removal at colonoscopy by an Advanced Endoscopist rather than requiring surgery.

Because a positive bowel screening test has around a one third chance of having large polyps on colonoscopy, this is a situation where the colonoscopy should be ideally performed by an Advanced Endoscopist as this will maximise your chances of having the polyp dealt with at a single colonoscopy, and also if a polyp cancer is present, will maximise the chances of a curative resection that prevents the need for surgery.  

What is a quality colonoscopy?

A quality colonoscopy can provide reassurance about your bowel cancer risk for years or even decades. A good result depends on proper bowel preparation and the skill of the colonoscopist. Skill levels vary, so it’s important to ask about the doctor’s performance measures.

Colonoscopy has evolved from just detecting cancer to preventing it by removing polyps. Studies show that a normal colonoscopy in people over 50 significantly lowers the risk of bowel cancer for 20 years, and even if a significant polyp is removed, the risk remains low for at least five years. However, this depends on the colonoscopy being high quality, meaning no significant polyps were missed.

Key Factors in a quality colonoscopy:

  1. Bowel Preparation:
    Proper bowel cleansing is critical. Follow the bowel preparation instructions carefully to ensure any findings, particularly polyps, are not missed due to residual stool.

  2. Colonoscopy Skill:
    The operator must thoroughly examine the bowel, carefully looking for polyps behind folds and in blind spots. A skilled colonoscopist will remove polyps safely and effectively.

  3. Performance Measures:
    Most colonoscopy units in NZ now audit colonoscopist performance, focusing on efficacy, patient comfort, and complication rates. Your colonoscopist should be able to provide these measures.

    • Caecal intubation rate: This measures how often the colonoscope reaches the end of the colon. A skilled colonoscopist should have a rate above 95%, with top performers above 98%.

    • Adenoma detection rate (ADR): This reflects the percentage of colonoscopies where significant polyps (adenomas) are found. A rate of at least 30% is expected in NZ. Lower rates may indicate missed polyps, which increases the risk of future cancer.

    • Withdrawal time: The colonoscopist should spend at least 6-10 minutes withdrawing the colonoscope to carefully examine the colon, as this is when most polyps are found.

  4. Patient Comfort:
    Colonoscopy should not be overly uncomfortable. If a colonoscopist frequently causes discomfort or uses large amounts of sedatives, it may indicate poor technique. Many patients find the procedure fascinating and experience minimal discomfort. Some patients prefer an an aesthetistist-administered sedation, but this is not usually necessary.

  5. Complications:
    The most common complication is missing a significant polyp, which could lead to cancer. The risk of missing a large polyp is 2-6%, and the risk of developing cancer after a colonoscopy is about 1 in 1000. This risk increases if the colonoscopist is fatigued, so avoid being the last patient of the day. Perforation, bleeding, or sedative complications are rare for basic colonoscopies but more common for therapeutic colonoscopies, where larger polyps are removed.

    For therapeutic procedures, it’s important to discuss the risks and what will be done if complications arise.