INTRODUCTION:

An advanced colorectal neoplasm (ACN) is a colorectal cancer, or a polyp that is 1 cm or larger or has high risk histology (villous elements or high grade dysplasia). 

The estimate of your patient’s chance of having an ACN was based on a prediction model that was developed and validated by Dr. Thomas Imperiale and colleagues at IU School of Medicine in an NCI-funded study of 4460 patients who were having their first screening colonoscopy (2993 in the derivation set and 1467 in the validations set).  (Imperiale et al. 2015)

Using this model, each patient is assigned points for five different risk factors – age, sex, waist circumference, smoking history and family history – and the points are added up to determine their risk level.

No estimate is perfect: a person’s true chance of having an ACN is impossible to know with 100% certainty.  But this validated way of estimating patient risk provides a good estimate.

ASSIGNING POINTS:

Here’s how the points are assigned:

pcori-2019-notification

DETERMINING RISK LEVEL:

A patient’s chance of having an ACN is estimated based on the total number of points they received.  A patient can have a total as low as 0 and as high as 12:

0 points = Very low risk = 2% chance of currently having an ACN
Out of 100 patients with this risk level, approximately 2 currently have an ACN.
This chance of having an ACN is far below average for people eligible for screening.

1-3 points = Low risk = 4% chance of currently having an ACN
Out of 100 patients with this risk level, approximately 4 currently have an ACN.
This chance of having an ACN is below average for people eligible for screening.

4-6 points = Moderate risk = 10% chance of currently having an ACN
Out of 100 patients with this risk level, approximately 10 currently have an ACN.
This chance of having an ACN is average for people eligible for screening.

7-12 points = High-average risk = 22 % chance of currently having an ACN
Out of 100 patients with this risk level, approximately 22 currently have an ACN.
This chance of having an ACN is above average for people eligible for screening.

Of note, ACN’s are much more likely to be pre-cancerous polyps 1 cm or larger or one with high risk pathology rather than cancers.

CHOOSING A SCREENING TEST:

All patients enrolled in the study can choose from any approved screening test, according to guidelines published by the American Cancer Society (ACS Cancer Screening Guidelines), the United States Preventive Services Task Force (US Preventive Services Task Force), and the American College of Gastroenterology (ACG Guidelines).

The most commonly used screening tests are colonoscopy and stool occult blood testing with the Fecal Immunochemical Test (FIT) or Cologuard.  Your patient may choose any approved test because their risk is not extremely elevated, as it is for those with inflammatory bowel disease, significant family history, or certain genetic conditions (Lynch, FHP).

Patients with VERY LOW or LOW risk:

A stool test (FIT or Cologuard) may be particularly appropriate for patients with this risk level.

  • There is a lower chance of these patients having a cancer or precancerous polyp that would be found and removed by colonoscopy, compared to people with a higher chance of having an ACN.
  • One of the concerns about the stool test is that it may not find a large polyp or cancer. But since these patients’ chance of having a large polyp or a cancer is low to begin with, the chance of the stool test missing one is small.

For patients with this risk level, some patients or providers may still prefer colonoscopy, and that is a perfectly reasonable choice, according to guidelines.

Patients with MODERATE risk:

Screening may be seen as being even more important in these patients than in patients with low or very low chance of having an ACN.  Either colonoscopy or stool tests (FIT or Cologuard) are perfectly appropriate for patients at this risk level. 

Patients with HIGH risk:

A screening colonoscopy may be particularly appropriate for patients with this risk level. 

  • The main advantage of colonoscopy is that it will find nearly every cancer or large polyp in the colon.
  • These patients have a higher chance of having a cancer or a polyp that can be found and removed by colonoscopy, compared to patients with lower risk levels.

For patients with this risk level, some patients or providers will still prefer a stool test (FIT or Cologuard), and that is a perfectly reasonable choice, according to guidelines.