Revising the suspected-cancer guidelines: Impacts on patients’ primary care contacts and costs

Abstract

Objectives: Exploring the impact of revising suspected-cancer referral guidelines on primary care contacts and costs. Methods: Participants had incident cancer (colorectal: n=2,000; ovary: n=763; pancreas: n=597) codes in the Clinical Practice Research Datalink or England cancer registry. Difference-indifferences analyses explored guideline impacts on contact days and non-zero costs between the first cancer feature and diagnosis. Participants were controls (“Old-NICE”), or “New-NICE” if their index feature was introduced during guideline revision. Model assumptions were inspected visually and by falsification tests. Sensitivity analyses re-classified participants who subsequently presented with feature(s) in the original guidelines as “Old-NICE”. For colorectal cancer, sensitivity analysis (n=3,481) adjusted for multimorbidity burden. Results: Median (interquartile range) contact days and costs were: 4 (2–7) and £117.69 (£53.23- £206.65) for colorectal; 5 (3-9) and £156.92 (£78.46-£272.29) for ovary, and 7 (4-13) and £230.64 (£120.78-£408.34) for pancreas. Revising ovary guidelines may have decreased contact days (incidence rate ratio 0.74, 95%CI 0.55-1.00, p=0.05) with unchanged costs, but parallel trends assumptions were violated. Costs decreased by 13% (equivalent to -£28.05, -£50.43 to - £5.67) after colorectal guidance revision, but only in sensitivity analyses adjusting for multimorbidity. Contact days and costs remained unchanged after pancreas guidance revision. Conclusions: The main analyses of symptomatic patients suggested that pre-diagnosis primary care costs remained unchanged after guidance revision for pancreatic cancer. For colorectal cancer, contact days and costs decreased in analyses adjusting for multimorbidity. Revising ovarian cancer guidelines may have decreased primary care contact days but not costs, suggesting increased resource-use intensity; however, there is evidence of confounding.