The Current Status of Breast Screening Practices and Modalities
There are differences in recommendations on screening healthy women for breast cancer worldwide. These differences are mainly attributed to the variations in interpretation of cost-benefit analyses. While in Europe women over 50 are recommended to have a mammography every two years, the American Cancer Society recommends that women aged 40 and older have a clinical breast examination and mammogram once a year. Women with a family history of breast cancer are referred to early examinations by diagnostic modalities such as X-ray mammography, 2-D ultrasound, computer tomography (CT), CT with computer-aided diagnosis (CAD), positron emission tomography (PET) scan, magnetic resonance imaging (MRI) and MRI with CAD.
Despite significant advances in these modalities, they have failed to provide an adequate, safe and complete solution for screening of the healthy female population either due to technological barriers or because of their prohibitively high cost. An ideal imaging modality would identify abnormal tissue, characterize and localize the abnormalities within the breast, and facilitate further examination or treatment. In reality, most technologies cannot achieve all the goals and thus, many research and development efforts have turned their focus on optimizing one goal at a time.
Imaging methodologies are conventionally used to map and differentiate structural differences in tumors, such as microcalcifications, tissue masses, angiogenesis, asymmetries, and architectural distortions to biologically or functionally distinguish between tumors and normal tissues. To date, the gold-standard for diagnostic breast imaging is X-ray mammography. In cases where diagnosis by mammography is not specific or in women at high risk, additional examinations by ultrasound or MRI are required. When mammograms result in positive diagnoses, a pathological biopsy test is preformed to determine whether the detected lesion or tumor is benign or malignant.