Will adherence to new guidance lead to missed cancer diagnoses? Evaluation of limiting symptomatic mammograms to over forties.

Within the United Kingdom, a recent change in "Best Practice Guidance" has suggested that mammograms for symptomatic breast patients, with a clinically benign examination, should be limited to those over 40 years . This has led to anxiety over missing cancer diagnoses in the 35-39 year-old age group. This study aimed to assess the impact of the new guidance upon a NHS Breast unit with a particular focus on safety. Two cancer data bases (BASO and SOMERSET) were used to identify thirty-three patients aged 35-39 years diagnosed with breast cancer between January 2007 and June 2011. Case notes were retrieved and retrospectively analyzed for trends during clinical (P1-P5) and radiological assessment (using Royal College Radiologists Breast Group classification-M1-5, U1-5). Sensitivity and false-negative rates for each modality were calculated. Sensitivities of clinical examination, mammography, and ultrasound for detecting malignancy were 72.7%, 78.8%, and 93.9%, respectively. Within the clinically benign group (P1 and P2), mammography and ultrasound showed sensitivities of detecting malignancy of 55.5% and 88.9%, respectively, with three extra cancers being identified by ultrasound when mammography was graded less than M3 (indeterminate lesion-requiring biopsy). Importantly, no cancers would have been missed if the new guidance had been adhered to. This study has shown that mammography has no additional diagnostic benefit as first-line imaging in symptomatic breast patients aged 35-39 years. It has confirmed that implementation of the new Best Practice Guidance is safe, when used in the setting of triple assessment, to ensure cancer diagnoses are not missed.