Measurement of tumour size in case selection for breast cancer therapy by clinical assessment and ultrasound

Aims. Clinical assessment of tumour size is often used to choose between mastectomy and primary medical therapy. Clinical and imaging modalities may have varying levels of accuracy across the range of tumour sizes. The aim of this study was to compare the accuracy of clinical measurement and ultrasound in discriminating palpable tumours up to 3 cm vs those greater than 3 cm. Methods. A prospective analysis of 111 consecutive patients with palpable breast cancer was performed. All women had clinical measurement by caliper and ultrasound assessment prior to any needle biopsy. Clinical measurement and ultrasound assessment of size were compared to pathological tumour size of the surgical specimen. Results. Both clinical and ultrasound measurement underestimate the size of larger tumours. The overall accuracy of clinical assessment and ultrasound examination in correctly identifying a 30 mm cut off was 70.3 and 77.5%, respectively. Ultrasound was significantly more accurate at determining the size of tumours <30 mm (p=0.007) but there was no significant difference between both modalities in assessing tumours greater than 30 mm. Conclusions. Ultrasound assessment of breast cancer size is more accurate than clinical assessment for tumours less than 30 mm. As clinical examination is as accurate on ultrasound for tumours greater than 30 mm, clinical assessment of tumour size alone is adequate to select patients for primary medical therapy or mastectomy.