Purpose: To assess the radiological workup outcome of incidental hypermetabolic findings in the breast and axilla, as detected on PET/CT examinations of patients without history of breast cancer.
Materials and Methods: The institutional review board approved this retrospective with a waiver for informed patient consent. A filtered computerized search of our institutional radiology information system (RIS) was conducted to find all patients who underwent breast imaging procedure between 2011-2016, and matched the word "PET". Patients with negative PET scans patients who were referred to PET scan due to radiological findings and patients with a history of breast cancer were excluded from the study. For the remaining final cohort, radiological reports, medical files and archived images were analyzed to summarize clinical and imaging characteristics. Statistical evaluation was applied to assess differences between features of benign and malignancy.
Results: The study included 43 patients (mean age 57.3 years) with abnormal hypermetabolic focal mammary or axillary FDG uptake on PET identified during the time span. The main indication for PET/CT was Lymphoma (n=14, 33%) and cervical carcinoma (n=7, 16%). 10 patients (23.2%) were diagnosed with breast cancer (7 IDC, 2 ILC and 1 DCIS). 7 more patients were diagnosed with metastatic disease. The remaining 26 patients without cancer had radiological clearance or benign findings, mostly reactive lymph nodes (n=5). Mean, max and normalized-to-liver SUV values of the cancer group were found to be significantly higher (p=0.05) than the respective values of the non-cancer group. Albeit, overlapping values were noticed.
Conclusion: Incidental breast or axillary focal uptake of FDG on PET performed for non-breast related indications is associated with significant rates of malignancy, in terms of primary or metastatic disease. Higher values of SUV may suggest malignancy, but lower values do not rule out cancer.
