Understanding Patient Preference on Colorectal Cancer Screening Options

Significance

A key to improving screening participation is patient acceptance of the testing method. Indeed, all screening modalities have benefits over time, and compliance with testing is essential for successful screening. A blood-based screening test can easily be part of a routine clinic visit, and the patient can complete the test while still at the clinic. Patients are accustomed to providing blood samples for other screening tests, such as cholesterol screening (the national screening rate was 87% in 2019), and the use of a blood-based CRC screening test is more in line with a patient's expectations of medical care. On January 19, 2021, the Centers for Medicare and Medicaid Services announced that the blood-based biomarker test is an appropriate CRC screening once every three years for Medicare patients when performed in a CLIA-certified laboratory, ordered by a treating physician, and the blood-based biomarker screening test has a sensitivity greater than or equal to 74% and a specificity greater than or equal to 90% in the detection of CRC.

The last decades have seen many discovery studies identifying promising biomarkers of CRC. Improving testing methods for blood-based CRC testing have been developed and implemented in clinical settings as well. The first blood-based CRC screening test, SEPT9 DNA (Epi proColon), was approved by the FDA in 2016 for persons at average risk for CRC who have chosen not to undergo screening by existing guideline-recommended methods. This study will offer a lab-developed Guardant SHIELD blood-based CRC screening test to patients who failed to complete a stool-based screening test or a colonoscopy six months after receiving an order from their providers. The Guardant SHIELD blood-based screening test will be free to the patients with an order from their providers. The Guardant SHIELD test is a multimodal blood-based colorectal neoplasia detection assay incorporating ctDNA (circulating tumor DNA) assessment of somatic mutations and tumor-derived methylation and fragmentomic patterns to maximize early-stage CRC detection sensitivity. Overall, the Guardant SHIELD blood-based test has a CRC sensitivity of 91% and a specificity of 94%, meeting the Centers for Medicare and Medicaid Services requirement (74% for sensitivity and 90% for specificity). All the blood samples collected in this study will be processed at the CLIA-certified Guardant Health Laboratory.

Compliance by age-eligible patients is essential to the success of any screening program. However, the acceptance by health care providers and the health care system is also critical, and especially colonoscopy remains the dominant modality for CRC in the U.S. Applying the current state of research evidence to health care involves fostering the adoption, implementation, spread, and sustainability of new evidence-based interventions to care. Furthermore, transferring effective interventions into real-world settings and maintaining them is a complicated, long-term process that requires complex phases of intervention diffusion. In this study, the investigators will examine the inclusion of a blood-based screening option to increase patient compliance with CRC screening while developing implementation strategies to facilitate the adoption of a new blood-based screening test at primary care clinics.

The overall goal of the study is two-fold: 1) examine patient preference when a blood-based CRC screening option is available, and compliance with CRC screening, especially among diverse and vulnerable populations; and 2) understand how to increase the adoption, implementation, and sustainability of an evidence-based screening method to improve CRC screening uptake and adherence.