Patterns of uptake in the subareolar plexus as detected by 18F-FDG PET/CT: Does gender or bra use matter?

Abstract

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Objectives : Among American women, the lifetime risk of breast cancer is approximately 13%. Lymphatic vessels play a major role in the spread of tumor cells outside the primary breast cancer site. The subareolar plexus is the main destination of the intraglandular lymph of the mammary gland. Differences in FDG breast uptake due to gender or breast compression, and any resulting reduction in perfusion and/or oxygenation, are unclear. The objective of the current study was to compare FDG uptake in the nipple and subareolar area of males versus females. In addition, we determined if a difference exists between bras users and non-bra users.

Methods : We retrospectively reviewed PET/CT scans of 144 known or suspected cancer patients and 9 normal volunteers (78 males, 75 females). Females were classified based on the presence and type of bra detected on the CT part of the PET/CT: braless (n=23), under wire bra (n=20), or non-under wire bra (n=32). A region of interest (ROI) was selected to include the nipple, areola and the subareolar area of each breast for each subject. Based on the ability to see the uptake in the desired area, ROI were generated on the PET or the CT parts of the PET/CT. Also, fused PET/CT images were used when needed. Patients with known or suspected breast cancer and or mastectomy were not included in the study.

Results : Female subjects had statistically significant increased FDG uptake in the nipple and subereolar region than their male counterparts (.61 ± .24 vs .39 ± .16, p.001). The difference in the uptake between women and men was statistically significant independent of the use or type of bra. In addition, bra users showed a statistically significant increase in uptake (.65 ± .23) compared to non-bra users (.51 ± .23), p=.001, but the difference between types of bra (under wire: .65±.27 versus non-under wire: .66±.22) was not statistically significant (p=.8).

Conclusions : Our study revealed a statistically significant higher suberolar FDG uptake in women than in men. Also, this uptake is statistically significant higher in bra users than in non-bra users. The gender difference is probably hormonal dependent; however, further studies are needed to investigate the relationship between breast compression from the use of bra and the development of breast cancer.