A colonoscopy tests for the cancer by finding irregularities and polyps in the colon and rectum, and accuracy in discovering those largely depends on the quality of the bowel preparation. Patients must clean out their bowels by drinking a solution that is diluted with clear fluids the day before the procedure.

However, doctors and nurses both acknowledge that these solutions can be difficult to drink, and patients will need to be in close proximity to a washroom during their bowel preparation.  These factors may make it difficult to discuss the preparation openly, potentially leading to postponement of the procedure.

“It’s important that physicians have a good discussion about what patients can expect and what they will experience,” says Dr. David Morgan, a gastroenterologist at St. Joseph’s Healthcare in Hamilton, ON. “A lot of patients don’t ask questions that weigh on their minds, and often, if they have the answers they’re reassured that things aren’t as scary as they otherwise might be.”

The drinking process

Patients generally have three options in how they drink the solution. There is a four litre volume that is pre-mixed, a two litre that is pre-mixed and the smallest volume, which is two sachets of 150mL each. The lowest volume option requires about three to four litres of additional regular everyday clear fluids such as  apple juice, ginger ale, Gatorade, white grape juice, white cranberry, tea or chicken broth, for example. Water alone  and milk are to be avoided.  Low volume options tend to be the most popular among patients.

“A lot of patients don’t ask questions that weigh on their minds, and often, if they have the answers they’re reassured that things aren’t as scary as they otherwise might be.”

“We have recently started doing split preparations where they drink half the night before and the other half the morning of the test,” says Usha Chahuan, a nurse and assistant professor at McMaster University’s nursing program.

“We found that since we’ve been doing that, patients have had fewer problems. For some, refrigerating the solution helps, whereas others may prefer little flavouring packages to sweeten it.”

Chahuan adds that patients could benefit from starting a low-fibre diet earlier than the three-day period leading up to the test, and sticking to clear liquids over that time, too. Those with heart or kidney conditions will have to go with either of the larger pre-mixed options, regardless.

Proper prep ‘important’

Gail Attara, president and CEO of the Gastrointestinal Society in Vancouver, B.C., says being strict with the process helps patients when it comes time to go through the procedure.

“During the colonoscopy, the physician can insert water into the colon and flush it around a little bit to help clear away some debris, but that creates a challenge because you’re irrigating the wrong way,” says Attara. “It’s really important that you don’t stall on bowel preparation because you can detect the cancer early and stop it.”

Dr. Morgan adds that good preparation tends to make the test easier to administer, as far as picking up polyps and identifying anything that might be cause for concern, particularly since any one of the solutions can do the job of flushing everything out.