Development and validation of a clinical prediction rule to identify suspected breast cancer: a prospective cohort studyReport as inadecuate

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BMC Cancer

, 14:743

Epidemiology, prevention and public health


BackgroundThe number of primary care referrals of women with breast symptoms to symptomatic breast units SBUs has increased exponentially in the past decade in Ireland. The aim of this study is to develop and validate a clinical prediction rule CPR to identify women with breast cancer so that a more evidence based approach to referral from primary care to these SBUs can be developed.

MethodsWe analysed routine data from a prospective cohort of consecutive women reviewed at a SBU with breast symptoms. The dataset was split into a derivation and validation cohort. Regression analysis was used to derive a CPR from the patient’s history and clinical findings. Validation of the CPR consisted of estimating the number of breast cancers predicted to occur compared with the actual number of observed breast cancers across deciles of risk.

ResultsA total of 6,590 patients were included in the derivation study and 4.9% were diagnosed with breast cancer. Independent clinical predictors for breast cancer were: increasing age by year adjusted odds ratio 1.08, 95% CI 1.07-1.09; presence of a lump 5.63, 95% CI 4.2-7.56; nipple change 2.77, 95% CI 1.68-4.58 and nipple discharge 2.09, 95% CI 1.1-3.97. Validation of the rule n = 911 demonstrated that the probability of breast cancer was higher with an increasing number of these independent variables. The Hosmer-Lemeshow goodness of fit showed no overall significant difference between the expected and the observed numbers of breast cancer χHL: 6.74, p-value: 0.56.

ConclusionsThis study derived and validated a CPR for breast cancer in women attending an Irish national SBU. We found that increasing age, presence of a lump, nipple discharge and nipple change are all associated with increased risk of breast cancer. Further validation of the rule is necessary as well as an assessment of its impact on referral practice.

KeywordsBreast cancer Diagnosis Primary care Electronic supplementary materialThe online version of this article doi:10.1186-1471-2407-14-743 contains supplementary material, which is available to authorized users.

Rose Galvin, Doireann Joyce contributed equally to this work.

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Author: Rose Galvin - Doireann Joyce - Eithne Downey - Fiona Boland - Tom Fahey - Arnold K Hill


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