Underutilization of Guideline-Recommended Mismatch Repair/Microsatellite Instability Biomarker Testing in Advanced Colorectal Cancer.

TitleUnderutilization of Guideline-Recommended Mismatch Repair/Microsatellite Instability Biomarker Testing in Advanced Colorectal Cancer.
Publication TypeJournal Article
Year of Publication2022
AuthorsPapke DJ, Lindeman NI, Schrag D, J Iorgulescu B
JournalCancer Epidemiol Biomarkers Prev
Date Published2022 Sep 02
KeywordsAdenocarcinoma, Adult, Biomarkers, Colorectal Neoplasms, DNA Mismatch Repair, Humans, Microsatellite Instability, Young Adult

BACKGROUND: In 2017, DNA mismatch repair/microsatellite instability (MMR/MSI) testing was nationally recommended for advanced colorectal cancers based on favorable immune checkpoint inhibitor responses among patients with MMR-deficient/MSI-high tumors.

METHODS: Patients ages ≥20-years-old presenting with stage IV colorectal adenocarcinoma from 2010 to 2017 were identified from the National Cancer Database. 2017 was the latest year with available testing utilization data. Patient, tumor, socioeconomic, and care setting characteristics were evaluated for association with upfront MMR/MSI testing in 2017 using multivariable logistic regression and average adjusted predicted probabilities (%AAP).

RESULTS: Among 72,830 stage IV colorectal cancers, upfront MMR/MSI testing levels increased from 16.4% in 2010 to 56.4% in 2017. For patients diagnosed in 2017 (i.e., following national recommendations, n = 10,022), testing levels were lower for older patients (Padj < 0.001), and were independent of patients' race/ethnicity and insurance status. Patients from the poorest quartile of households received less testing [49.6%AAP, 99.9% confidence interval (CI) 45.5-53.7] than patients from the 3rd (56.9%AAP, 99.9% CI, 53.3-60.6; Padj < 0.001) or 4th quartiles (57.6%AAP, 99.9% CI, 54.3-60.9; Padj < 0.001). Although testing levels improved most at community programs, they remained lower in 2017 (46.6%AAP, 99.9% CI, 41.0-52.1) compared with academic/NCI-designated comprehensive cancer centers (62.8%AAP, 99.9% CI, 59.7-65.8; Padj < 0.001).

CONCLUSIONS: Upfront MMR/MSI testing utilization for patients with advanced colorectal cancer has increased but there is still substantial need for optimization. Testing utilization disproportionately lagged for patients who were older, from the poorest quartile of households, or managed at community cancer programs.

IMPACT: Our findings indicate opportunities for improving rates of MMR/MSI testing and reporting, possibly through incorporation into quality control and accreditation metrics.

Alternate JournalCancer Epidemiol Biomarkers Prev
PubMed ID35767976
PubMed Central IDPMC9444979
Grant ListK12 CA090354 / CA / NCI NIH HHS / United States
P30 CA008748 / CA / NCI NIH HHS / United States
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