Is mammogram important for the staging of breast cancer?

Breast-conserving surgery is currently the management practice of choice for early-stage breast cancer, because, when combined with radiation therapy, it has survival rates similar to those of mastectomy, provided there is appropriate patient selection (1).

The proper choice is important as the Imaging studies are used to provide a road map for the surgeon to help him or her obtain clear margins-which, in turn, is considered essential in order to avoid recurrent disease (1).

It is well established that breast MRI is by far superior to mammography, with or without concomitant ultrasound, for the local staging of breast cancer. MRI allows the most accurate delineation of the size and the local extent of cancer, including the depiction of multifocal or multicentric or contralateral disease MRI offers the highest sensitivity for demonstrating intraductal extensions around invasive cancers. Due to its very high negative predictive value, MRI can be used to confidently exclude the presence of breast cancer, and, thus, avoid unnecessary surgery (2).

Microcalcifications constitute approximately 31% of identified lesions on screening mammogram and missed breast carcinomas by MRI are those low grade invasive cancers (3)(4). In a study performed by Bennani-Baity et al, 10% of the false negative MRI results were microcalcifications identified only on mammogram (5).

While mammography sensitivity is somewhat lower in women with extremely dense breasts, yet it  is the only test that can reliably detect suspicious pathological calcifications and diagnosis early stage of breast cancer.

In the current case, MR study confirmed the characterization and the extension of the right breast disease as was presented earlier by ultrasound. According to that modality the disease is confined to the upper outer quadrant

Biopsy was scheduled and the pathology report revealed invasive ductal carcinoma grade II.

Presence of carcinoma necessitates the request to perform a mammogram: the right breast showed upper outer focal area of distortion and additional upper quadrants and retroareolar regional clusters of malignant looking microcalcifications.

Now it is obvious that MR imaging in this case was insufficient to provide the proper dimensions of the disease and consequently underestimated the extension.

The patient was of a young age and the soft tissue infiltration of the right breast was within range and so the expected surgery to be conservative especially with absence of infiltrated axillary nodes, however the presence of wide range of clustered microcalcifications and the inflammatory changes of the breast altered the choice of management.

The patient had undergone right breast mastectomy.

Relying only on the MR images without a support by mammogram would have affected the prognosis and ultimately the survival rate of the disease.

Teaching Points:

In case of malignancy mammogram should go hand in hand with MR imaging to properly stage carcinoma before surgery.

Contrast enhanced mammogram could handle the drawback of the MRI being not a suitable modality that could visualize calcifications yet, MRI is still needed to asses, chest wall invasion, axillary nodes and give an idea about the pulmonary and hepatic statues.

Final Diagnosis

Right breast invasive ductal carcinoma, grade II,  ER -ve, PR –ve and Her+2 enriched and Ki 67 40%.

Keywords:
Mammogram, MR mammography, Breast cancer; Cancer staging; Breast calcifications; Ductal carcinoma insitu.