When clinical practice is governed by evidence-based guidelines and there is consensus about their validity, practice variation should be minimal.
For areas in which evidence gaps exist, greater variation is expected.
Dr Jane Weeks and colleagues systematically assessed interinstitutional variation in management decisions for 4 common types of cancer.
The team performed a multi-institutional, observational cohort study of patients with cancer diagnosed between 2006 through 2011.
The researchers evaluated 18 cancer centers participating in the formulation of treatment guidelines and systematic outcomes assessment through the National Comprehensive Cancer Network.
The team identified 25,589 patients with incident breast cancer, colorectal cancer, lung cancer, or non-Hodgkin lymphoma.
|Interinstitutional variation was high for 20% of oncology management decisions|
|Annals of Internal Medicine|
Interinstitutional variation for 171 binary management decisions with varying levels of supporting evidence.
For each decision, variation was characterized by the median absolute deviation of the center-specific proportions.
The team observed that interinstitutional variation was high for 20% of oncology management decisions, including 41% of decisions for non-Hodgkin lymphoma, 21% for breast cancer, 15% for lung cancer, and 12% for colorectal cancer.
The researchers noted that 46% of high-variance decisions involved imaging or diagnostic procedures, and 37% involved choice of chemotherapy regimen.
The evidence grade underpinning the 35 high-variance decisions was category 1 for 0%, 2A for 49%, and 2B/other for 51%.
Dr Weeks' team comments, "The substantial variation in institutional practice manifest among cancer centers reveals a lack of consensus about optimal management for common clinical scenarios."
"For clinicians, awareness of management decisions with high variation should prompt attention to patient preferences."
"For health systems, high variation can be used to prioritize comparative effectiveness research, patient–provider education, or pathway development."