The effect of age, menopausal state, and breast density on (18)F-FDG uptake in normal glandular breast tissue

Theoretically, the degree of (18)F-FDG uptake in the glandular tissues of the normal breast can affect the detection of breast cancer. The aim of this prospective study was to investigate relationships among age, menopausal state, and breast density and determine whether they affect (18)F-FDG uptake in normal glandular breast tissue.

Among 250 newly diagnosed breast cancer patients, 149 patients (mean age +/- SD, 50.9 +/- 9.70 y; range, 32-77 y) were analyzed because they had normal contralateral breasts confirmed by MRI, mammography, and (18)F-FDG PET examinations. PET images were acquired 60 +/- 2 min after the administration of (18)F-FDG (5.2 MBq/kg of body weight). The maximum and average standardized uptake value (SUVmax and SUVavg, respectively) of (18)F-FDG were calculated in the normal breast. Patients were divided into groups according to qualitative breast density and menopausal state. Descriptive statistics and 2-factorial analysis of covariance were used to assess the effects of qualitative breast density, menopausal state, and age on SUVmax and SUVavg. Pearson chi(2) was used to test the relationship between menopausal state and qualitative breast density.

The average age of patients with nondense breasts was significantly higher than that of patients with dense breasts (P < 0.01). Also, breast density related to menopausal state (P < 0.05). Dense breasts had an average SUVmax of 1.243 and mean SUVavg of 0.694, whereas nondense breasts had a mean SUVmax of 0.997 and mean SUVavg of 0.592. Analysis of covariance indicated that density and the linear effect of age were significant with regard to both SUVmax and SUVavg. After removing the linear effect of age, menopausal state had no effect on SUVmax and SUVavg.

(18)F-FDG uptake significantly decreases as age increases and breast density decreases. Age and qualitative breast density are independent factors and significantly affect (18)F-FDG uptake for both SUVmax and SUVavg. Menopausal state had no effect on SUVmax and SUVavg.