Breast-specific gamma imaging (BSGI) provided high sensitivity for the detection of atypical, high-risk breast lesions, which could help physicians identify candidates for preventive treatment, according to a study published in the June issue of Academic Radiology.
BSGI, which detects malignancies physiologically, has emerged as an adjunct to mammography and ultrasound in the detection and follow-up of breast cancer. In addition to detecting cancers, BSGI also indicates other areas of increased metabolism in the breast, such as nonmalignant lesions including atypical ductal hyperplasia (ADH) and lobular neoplasia.
These nonmalignant lesions have been considered false positives in previous studies. However, ADH represents a precursor to carcinoma, and women with ADH have a four- to 10-fold increased risk of developing breast cancer. Lobular neoplasia is associated with a comparable increased risk for future breast cancer. Women with one type of lobular neoplasia, lobular carcinoma in situ (LCIS), may be recommended for chemoprevention.
“Identifying women with ADH or lobular neoplasia is important as atypical lesions increases a woman’s risk for breast cancer and thus may impact screening and treatment recommendations,” wrote Caroline M. Ling, MD, from the breast imaging and interventional center at George Washington University in Washington, D.C., and colleagues.
Thus, Ling et al devised a study to evaluate the sensitivity of BSGI in detecting ADH and lobular neoplasia.
The researchers mined the pathology database to identify all women with ADH or lobular neoplasia as the highest-risk lesion at minimally invasive biopsy or surgical excision and cross-referenced this group with all patients who underwent BSGI between January 2006 and July 2009. The final study group comprised 15 patients.
Patients underwent BSGI for three reasons: to evaluate indeterminate or suspicious findings on mammography, to evaluate for occult lesions in a newly diagnosed cancer or to screen high-risk patients, according to Ling and colleagues.
A total of 100 percent of patients with surgically confirmed ADH or lobular neoplasia had a positive BSGI result, yielding 100 percent sensitivity. The researchers noted that increased radiotracer uptake on BSGI can indicate both malignant and atypical lesions.
Ling and colleagues also referred to the current legislative momentum in the U.S., with more states requiring supplemental screening be offered to women with dense breasts. BSGI may provide an alternative to MRI among dense-breasted women who are not candidates for MRI, according to the researchers. The modality also may complement mammography and MRI by identifying lesions that require further workup.
In addition, BSGI may identify occult lesions in women newly diagnosed with DCIS or breast cancer. Although studies have demonstrated that BSGI or MRI can detect such lesions, the routine preoperative use of BSGI or MRI remains controversial, according to Ling and colleagues. However, detection of high-risk lesions among some women at high risk for recurrent cancer could help inform decisions about prophylactic mastectomy.
BSGI may be applied for multiple purposes, concluded the researchers: the detection of ADH and lobular neoplasia and the evaluation of women at increased risk of breast cancer and of women newly diagnosed with breast cancer.