[Detection of invasive breast lobular carcinoma by image analysis: comparison between mammography and ultrasound]

Early detection of lobular cancer has for long implied a challenge for diagnostic imaging due to the peculiar histology it presents that makes clinical and radiology detection rather difficult.

The aim of our study was to compare the sensitivity and specificity of mammography and ultrasound for the diagnosis of invasive breast lobular carcinoma.

This is a retrospective study of women with histopathological diagnosis of invasive breast lobular carcinoma in the period between September 2006 and August 2009. All patients underwent mammography and ultrasound. The final pathology report was used as reference standard and the sensitivity and specificity of mammography and ultrasound were evaluated statistically using chi-square test (chi2).

The analysis included 654 patients who underwent biopsy. Among them, 148 (22.62%) were positive and 506 (77.37%) negative for cancer. The average age was 48 years (range 18-89). The sensitivity of ultrasound was higher in the group of invasive lobular cancer (ILC) in 14/14 (100%) cases, in contrast to 87/111 (78%) cases of invasive ductal carcinoma (IDC) and 9/18 (50 %) cases of ductal carcinoma in situ (DCIS). The mammography showed greater sensitivity in the group of DCIS in 17/18 (94%) cases, unlike 9/14 (64%) cases of ILC and 89/111 (80%) cases of IDC.

Ultrasound improves the detection of ILC with sensitivity up to 100% compared to 64% by mammography. The combination of both diagnostic tests showed sensitivity equal to the ultrasound, but it decreased 30% the specificity in this group.