Diagnostic accuracy of follow-up tests for detecting colorectal cancer recurrences in primary care: A systematic review and meta-analysis

Introduction: Traditionally, follow-up of colorectal cancer (CRC) is performed in secondary care. In new models of care, the screening part care could be replaced to primary care. We aimed to synthesise evidence on the diagnostic accuracy of commonly used screeners in CRC follow-up applicable in primary care: carcinoembryonic antigen (CEA), ultrasound and physical examination. Methods: Medline, EMBASE, Cochrane Trial Register and Web of Science databases were systematically searched. Studies were included if they provided sufficient data for a 2 × 2 contingency tables. QUADAS-2 was used to assess methodological quality. We performed bivariate random effects meta-analysis, generated a hypothetical cohort, and reported sensitivity and specificity. Results: We included 12 studies (n = 3223, median recurrence rate 19.6%). Pooled estimates showed a sensitivity for CEA (≤ 5 μg/l) of 59% [47%–70%] and a specificity of 89% [80%–95%]. Only few studies reported sensitivities and specificities for ultrasound (36–70% and 97–100%, respectively) and clinical examination (23% and 27%, respectively). Conclusion: In practice, GPs could perform CEA screening. Radiological examination in a hospital setting should remain part of the surveillance strategy. Personalised algorithms accounting for recurrence risk and changes of CEA-values over time might add to the diagnostic value of CEA in primary care.