18F-Fluoroestradiol Tumor Uptake Is Influenced by Structural Components in Breast Cancer. (November 2021) - Takahashi, Mizuho
Abstract : Purpose: Estrogen receptor (ER) is expressed in the majority of invasive breast cancer and is an important prognostic indicator. The tumor stroma also plays an important role in disease progression. This study evaluated the effect of stromal components on 16α-[ 18 F]-fluoro-17β-estradiol ( 18 F-FES) uptake in breast cancer and proposed a partial-volume correction method for 18 F-FES PET based on histopathological analyses. Patients and Methods: Fifteen patients with biopsy-confirmed breast cancer underwent preoperative 18 F-FES PET. Estrogen receptor expression in biopsy specimens was assayed by immunohistochemistry, cellular components in surgical specimens were measured using hematoxylin-eosin staining, and nuclear components in surgical and biopsy specimens were measured using Azan-Mallory staining. The relationship between 18 F-FES SUV of the primary tumor and histopathological findings including ER expression, the Allred score, ER-positive cellular component ratio, and ER-positive nuclear component ratio (NCR) was examined. The relationship between stroma-free 18 F-FES SUV and ER expression was also examined. Results: 18 F-FES uptake was not significantly positively correlated with ER expression ( r = 0.44, P = 0.10). 18 F-FES uptake was significantly correlated with the Allred score, ER-positive cellular component ratio, and ER-positive NCR in surgical specimens (ρ = 0.60, P = 0.02; r = 0.55, P = 0.03; and r = 0.65, P = 0.01, respectively). 18 F-FES uptake was predominantly correlated with ER-positive NCR in biopsy specimens ( r = 0.84, P < 0.001). Stroma-free 18 F-FES SUV was significantly correlated with ER expression ( r = 0.78, P < 0.01). Conclusions: 18 F-FES PET predominantly demonstrates the level of ER expression in breast cancer cell nucleus. Although tumor 18 F-FES uptake is affected by the degree of stromal components, the partial volume effect on the uptake can be corrected by stroma-volume fraction in Azan-Mallory staining.