Initial Studies with 11C-Vorozole PET Detect Overexpression of Intratumoral Aromatase in Breast Cancer
| Autor: | Mouna Tahmi, Krystal Airola, Jasbeer Dhawan, Jules Cohen, Anat Biegon, Kenneth R. Shroyer, Patrick Bonilla, Dinko Franceschi, Deborah Pareto |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty medicine.drug_class Urology Breast Neoplasms 03 medical and health sciences Aromatase 0302 clinical medicine Breast cancer Biopsy medicine Humans Radiology Nuclear Medicine and imaging Carbon Radioisotopes Aged biology medicine.diagnostic_test business.industry Letrozole Middle Aged Triazoles medicine.disease Immunohistochemistry 030104 developmental biology Oncology Estrogen Positron-Emission Tomography 030220 oncology & carcinogenesis Vorozole biology.protein Hormonal therapy Female business medicine.drug |
| Zdroj: | J Nucl Med |
| ISSN: | 2159-662X 0161-5505 |
| Popis: | Aromatase inhibitors are the mainstay of hormonal therapy in estrogen receptor–positive breast cancer, although the response rate is just over 50% and in vitro studies suggest that only two thirds of postmenopausal breast tumors overexpress aromatase. The goal of the present study was to validate and optimize PET with (11)C-vorozole for measuring aromatase expression in postmenopausal breast cancer in vivo. Methods: Ten newly diagnosed postmenopausal women with biopsy-confirmed breast cancer were administered (11)C-vorozole intravenously, and PET emission data were collected between 40 and 90 min after injection. Tracer injection and scanning were repeated 2 h after ingestion of 2.5 mg of letrozole. Mean and maximal SUVs and ratios to nontumor tissue in the contralateral breast were determined at baseline and after letrozole. Biopsy specimens from the same tumors were stained for aromatase using immunohistochemistry and evaluated for stain intensity and the percentage of immune-positive cells. Results: Seven of the 10 women (70%) demonstrated increased mean focal uptake of tracer (SUV ratio > 1.1) coinciding with the mammographic location of the lesion, whereas the other 3 women (30%) did not (SUV ratio ≤ 1.0). All patients with an SUV ratio above 1.1 had mean SUVs above 2.4, and there was no overlap (SUV ratio ≤ 1; SUV(mean), 0.8–1.8). The SUV ratio relative to breast around tumor was indistinguishable from the ratio to contralateral breast. Pretreatment with letrozole reduced tracer uptake in most subjects, although the percentage of blocking varied across and within tumors. Tumors with a high SUV in vivo also showed a high immunohistochemical staining intensity. Conclusion: PET with (11)C-vorozole is a useful technique for measuring aromatase expression in individual breast lesions, enabling noninvasive quantitative measurement of baseline and posttreatment aromatase availability in primary tumors and metastatic lesions. |
| Databáze: | OpenAIRE |
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