A recent study was conducted to assess the mammographic appearance of breast cancer exhibiting a basal phenotype, and to determine whether these features facilitate earlier detection of these tumors, which tend to have a poor prognosis.

Methodology
Over a 12-year period, invasive breast cancers that were recorded in women <=70 years of age were identified.

Those cancers identified on pathology to be of the basal phenotype were noted.

Of those, mammographic features were recorded, including qualification of a mass as well-defined, ill-defined, or spiculated.

Also, architectural distortion, focal asymmetry, or microcalcifications were identified.

If >1 finding was present, the nondominant characteristics were also included in the descriptions.

Five experienced breast imagers, who were blinded to the pathology results, recorded the mammographic features.

The data sets were combined to identify cases where mammographic appearance at screening detection was recorded, and the breast tumor was classified as having basal or nonbasal phenotype.

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Results
356 screening-detected cases of invasive breast cancer with basal phenotype were identified, and 309 had the nonbasal phenotype.

For both types, the dominant mammographic feature was a mass with either ill-defined or spiculated margins.

Basal-phenotype tumors were significantly more likely to appear as ill-defined masses on mammograms.

Nonbasal-phenotype tumors were significantly more likely than basal tumors to exhibit marginal spiculation.

Comedo calcification was seen more frequently with basal tumors as well.

When tumor grade was taken into account, these findings persist, showing that differences in mammographic appearance are not simply due to tumor grade.

Conclusions
In the assessment of characteristics of basal-phenotype breast tumors, these tumors are less likely to have spiculation, more likely to manifest as an ill-defined mass, and more likely to be found in association with comedo calcification.

Breast tumors with basal phenotype have a different mammographic appearance than nonbasal tumors and may explain the good prognostic value of mammographic spiculation.

Reviewer’s Comments
This article is interesting in that it acts to correlate mammographic findings with actual histology, with the idea that basal-phenotype tumors are more aggressive. How will this affect everyday practice?

Regardless of mammographic findings suggesting more aggressive tumors, the lesions will still be subjected to the same algorithm of imaging workup, followed by biopsy, and ultimately surgery and/or neoadjuvant therapy as per true findings at pathology.

Author: Basil Hubbi, MD

Reference:
Luck AA, Evans AJ, et al. Breast Carcinoma With Basal Phenotype: Mammographic Findings. AJR; 2008; 191 (August): 346-351

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