Staging primary breast cancer. Are there tumour pathological features that correlate with a false-negative axillary ultrasound?

AIM: To investigate whether the histopathological characteristics of primary breast cancer tumours could predict the likelihood of false-negative axillary ultrasound.
MATERIALS AND METHODS: Screening and symptomatic patients were identified from pathology records and imaging and pathology records reviewed. True and false-negative axillary staging ultrasound groups were compared statistically in terms of tumour size, pathological type and grade, lymphovascular invasion, and oestrogen receptor (ER) status.
RESULTS: Of 155 women with normal ultrasounds, 45 (29%) were node positive at axillary surgery. Breast tumour size was significantly different with the average size smaller in the true-negative group: 21 versus 30 mm (p < 0.02). The histological type varied significantly between the groups, with more lobular carcinomas in the false-negative group [6/110 (5%) versus 6/45 (13%), p < 0.001]. The false-negative group was also more likely to show lymphovascular invasion in the breast [6/110 (5%) versus 14/45 (31%), p < 0.001]. There was no significant difference in tumour grade or ER status.
CONCLUSION: The present study has found significant differences in tumour characteristics between women with true-negative and false-negative axillary staging ultrasound in terms of size, primary tumour histological type and presence of lymphovascular invasion. In particular, axillary ultrasound in primary lobular carcinoma may be less accurate and a negative result is more likely to be spurious than with primary ductal carcinomas.