A National Survey of Adoption of the 2018 American Cancer Society Colorectal Cancer Screening Guideline in Primary Care

Introduction

Recent data has shown increasing incidence of colorectal cancer (CRC) among those younger than 50 years of age.^{1, 2} In response, the American Cancer Society (ACS) introduced new guidelines in May 2018 that recommend initiation of CRC screening in average risk adults at age 45—five years earlier than existing recommendations from the U.S. Preventive Services Task Force (USPSTF) and U.S. Multi-Society Task Force on Colorectal Cancer (MSTF).^3–5 Most screening colonoscopies are ordered directly by primary care providers (PCPs) via “direct” or “open access” (without an intervening GI clinic visit).^{6, 7} Given that the decision to initiate CRC screening often begins with PCPs, awareness of the guidelines by PCPs is a necessary prerequisite to implement screening. The degree to which PCPs are aware of new ACS recommendations (knowledge diffusion) and have adopted them in clinical practice (implementation) is unknown.

Methods

We developed a survey to assess PCP awareness and adoption of the May 2018 ACS recommendations, as part of a broader survey about anemia. The questionnaire was iteratively modified based on feedback from PCPs and survey experts. The survey was administered online in August 2019 via the American College of Physicians’ (ACP) Internal Medicine Insiders Panel, a nationally representative group of internal medicine (IM) physicians selected through stratified random sampling as representative of the ACP membership. Inclusion criteria included practicing outpatient general IM and having completed residency. Survey responses were summarized using proportions, and summary statistics were reported for continuous variables. Statistical analysis was performed using SAS 9.4 (SAS Institute, Cary, NC).

Results

The survey was distributed electronically via the ACP Insiders Panel to 633 individuals who met inclusion criteria; 2 could not be reached (n=631 received an invitation). Of the 631 who received an invitation, 356 responded (response rate = 56.4%, n=356/631), and 31 were excluded (based on screening questions), for an adjusted eligible sample size of 600, with 325 completed surveys (completion rate 54.1%, n=325/600). Baseline demographic characteristics were assessed (Table 1).

Table 1.

Respondent characteristics (n = 325, 54% response rate).

Characteristic
Years in clinical practice	Mean = 19.8 years (range: 1–45 years)
Region
Urban	129 (39.7%)
Suburban	167 (51.4%)
Rural	29 (8.9%)
Gender
Male	180 (55.4%)
Female	131 (40.3%)
Prefer not to answer	14 (4.3%)
Race
Asian	80 (24.6%)
Black or African American	6 (1.9%)
White	193 (59.4%)
Other	7 (2.2%)
Prefer not to answer	39 (12%)
Affiliated Medical school
Yes	120 (36.9%)
No	205 (63.1%)
Board Certified Internal Medicine
Yes	315 (96.9%)
No	10 (3.1%)
Practice Setting
Single-specialty office	125 (38.5%)
Multispecialty office	90 (27.7%)
Medical school/academic medical center	34 (10.5%)
US government clinic (including VA/military)	23 (7.1%)
Hospital-based	21 (6.5%)
Free standing ambulatory care or urgent care center	10 (3.1%)
Institution	5 (1.5%)
Other	17 (5.2%)
Percentage of time
All outpatient	231 (71.1%)
Primarily outpatient with some inpatient	75 (23.1%)
Primarily inpatient with some outpatient	10 (3.1%)
Equal outpatient and inpatient	9 (2.8%)

The majority of respondents (77.2%, 251/325) reported being aware of the 2018 ACS recommendations. Of those aware of the recommendations, only 27.1% (68/251) reported that they had changed their practice (Supplemental Figure 1). Of the 68 respondents who reported a change in their clinical practice, 50% (34/68; or 10.5% of all respondents, 34/325) reported starting routine CRC screening prior to age 50: 41.2% of them (28/68) starting at age 45–49 (as recommended by ACS), 8.8% (6/68) of them starting at age 40–44 (earlier than recommended by ACS), and 50% of them (34/68) starting between ages 50–60 (later than recommended by ACS). There was no statistically significant difference in knowledge of the 2018 ACS guideline and providers’ academic affiliation, gender, or years in practice. Among all respondents, providers who reported generally being reluctant to “watch and wait” in their typical clinical practice were significantly more likely to recommend screening colonoscopy prior to age 50 (OR 4.1, CI 95% 1.7–9.9).

Discussion

With multiple CRC screening guidelines available, there may be a lag for new guidelines to reach PCPs and additional time before new guidelines become implemented in clinical practice.⁸ Moreover, when guidelines are discordant on screening initiation, PCPs may prefer to rely upon more familiar and credible existing guidelines. In this nationally representative sample of U.S. IM PCPs sampled in August 2019, we found widespread awareness (77.2%) of the 2018 ACS CRC screening guideline (which had been issued 15 months prior). However, despite awareness of this guideline, the changes in clinical practice had relatively limited impact to date. By self-report, only a minority of those aware of the 2018 ACS guideline (27.1%) reported a change in their clinical practice. This finding is important as it demonstrates that although updates to CRC guidelines may diffuse rapidly, this diffusion does not necessarily lead to changes in clinical practice. Indeed, there may be multiple barriers to implementation of new guidelines that need to be addressed.⁸ While this survey did not address these barriers explicitly, implementation of a new CRC screening strategy requires agreement by PCPs, patients (who need to be willing to start screening earlier), gastroenterologists (available to perform additional procedures), and coverage by insurers (who would need to pay for procedures at an earlier age). Additionally, existing clinical decision support systems are likely to continue to “flag” screening initiation at age 50 in many settings. Limitations include possible response bias, with respondents potentially more engaged with ACP or more knowledgeable about these guidelines. Future work should examine stakeholder attitudes towards early screening as well as pragmatic challenges associated with implementation of such measures.