Breast cancer in 35 to 39 year olds and imaging: is changing to ultrasound without mammography going to be safe? What are the workload implications?

Introduction

New guidelines suggest that ultrasound should replace mammography as the primary imaging test for 35 to 39 year olds in symptomatic outpatient clinics. We currently use clinical examination, clinically guided fine needle aspiration and mammograms for women aged 35+ as initial triple assessment. We wanted to understand the implications of introducing the guidelines, based on our current practice.

Methods

We reviewed our workload and cancer detection in symptomatic 35 to 39 year olds attending breast outpatients in our district general hospital over the past 18 months.

Results

Mammograms were taken on all symptomatic patients unless pregnant or breastfeeding. Seven hundred and fourteen patients had mammograms and 442 patients had ultrasound. This was performed on most patients found to have clinically palpable lumps, and on anyone with a clinical examination graded as uncertain suspicious or malignant, or with abnormal mammograms, or with abnormal results on clinically guided needle cytology. Fourteen patients were found to have breast cancer. All 14 had ultrasounds graded as uncertain, suspicious or malignant, an indication for diagnostic core biopsy. Thirteen cancer patients had mammograms. Two were graded as benign and 11 as uncertain or worse. Five cancer patients had clinically normal or benign breast examinations, including one with a benign mammogram report.

Conclusions

Ultrasound missed no cancers but mammograms missed two out of 13. This supports implementing the guidelines. However, this would mean a 38% increase in the number of ultrasounds, 15 extra each month. This extra ultrasound capacity may be hard to provide but will be offset by fewer mammograms.