PURPOSE: This study evaluated the ability of 18F-Fluorodeoxyglucose (FDG) and 18F-Fluorothymidine (FLT) imaging with positron emission tomography (PET) to measure early response to endocrine therapy from baseline to just prior to surgical resection in estrogen receptor positive (ER+) breast tumors. METHODS: In two separate studies, women with early stage ER+ breast cancer underwent either paired FDG-PET (n = 22) or FLT-PET (n = 27) scans prior to endocrine therapy and again in the pre-operative setting. Tissue samples for Ki-67 were taken for all patients both prior to treatment and at the time of surgery. RESULTS: FDG maximum standardized uptake value (SUVmax) declined in 19 of 22 lesions (mean 17% (range -45 to 28%)). FLT SUVmax declined in 24 of 27 lesions (mean 26% (range -77 to 7%)). The Ki-67 index declined in both studies, from pre-therapy (mean 23% (range 1 to 73%)) to surgery [mean 8% (range < 1 to 41%)]. Pre- and post-therapy PET measures showed strong rank-order agreement with Ki-67 percentages for both tracers; however, the percent change in FDG or FLT SUVmax did not demonstrate a strong correlation with Ki-67 index change or Ki-67 at time of surgery. CONCLUSIONS: A window-of-opportunity approach using PET imaging to assess early response of breast cancer therapy is feasible. FDG and FLT-PET imaging following a short course of neoadjuvant endocrine therapy demonstrated measurable changes in SUVmax in early stage ER+ positive breast cancers. The percentage change in FDG and FLT-PET uptake did not correlate with changes in Ki-67; post-therapy SUVmax for both tracers was significantly associated with post-therapy Ki-67, an established predictor of endocrine therapy response.

• Klíčová slova
• Aromatase inhibitors, ER+ breast cancer, FDG-PET, FLT-PET, Ki-67,
• MeSH
• antigen Ki-67 metabolismus   MeSH
• dideoxynukleosidy terapeutické užití   MeSH
• dospělí MeSH
• fluorodeoxyglukosa F18 terapeutické užití   MeSH
• inhibitory aromatasy terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mastektomie MeSH
• nádorové biomarkery metabolismus   MeSH
• nádory prsu diagnostické zobrazování   farmakoterapie   metabolismus   chirurgie   MeSH
• neoadjuvantní terapie MeSH
• pozitronová emisní tomografie MeSH
• radiofarmaka terapeutické užití   MeSH
• receptory pro estrogeny metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• alovudine MeSH Prohlížeč
• antigen Ki-67 MeSH
• dideoxynukleosidy MeSH
• fluorodeoxyglukosa F18 MeSH
• inhibitory aromatasy MeSH
• nádorové biomarkery MeSH
• radiofarmaka MeSH
• receptory pro estrogeny MeSH

Histone deacetylase inhibitors (HDACIs) may overcome endocrine resistance in estrogen receptor-positive (ER+) metastatic breast cancer. We tested whether 18F-fluoroestradiol PET imaging would elucidate the pharmacodynamics of combination HDACIs and endocrine therapy. Methods: Patients with ER+/human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer with prior clinical benefit from endocrine therapy but later progression on aromatase inhibitor (AI) therapy were given vorinostat (400 mg daily) sequentially or simultaneously with AI. 18F-fluoroestradiol PET and 18F-FDG PET scans were performed at baseline, week 2, and week 8. Results: Eight patients were treated sequentially, and then 15 simultaneously. Eight patients had stable disease at week 8, and 6 of these 8 patients had more than 6 mo of stable disease. Higher baseline 18F-fluoroestradiol uptake was associated with longer progression-free survival. 18F-fluoroestradiol uptake did not systematically increase with vorinostat exposure, indicating no change in regional ER estradiol binding, and 18F-FDG uptake did not show a significant decrease, as would have been expected with tumor regression. Conclusion: Simultaneous HDACIs and AI dosing in patients with cancer resistant to AI alone showed clinical benefit (6 or more months without progression) in 4 of 10 evaluable patients. Higher 18F-fluoroestradiol PET uptake identified patients likely to benefit from combination therapy, but vorinostat did not change ER expression at the level of detection of 18F-fluoroestradiol PET.

• Klíčová slova
• ER+ breast cancer, FES, estrogen receptors, metastatic breast cancer, vorinostat,
• MeSH
• dospělí MeSH
• estradiol analogy a deriváty   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metastázy nádorů MeSH
• nádory prsu diagnostické zobrazování   metabolismus   patologie   MeSH
• počítačové zpracování obrazu MeSH
• pozitronová emisní tomografie * MeSH
• receptor erbB-2 metabolismus   MeSH
• receptory pro estrogeny metabolismus   MeSH
• senioři MeSH
• vorinostat farmakologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky, fáze II MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• 16-fluoroestradiol MeSH Prohlížeč
• ERBB2 protein, human MeSH Prohlížeč
• estradiol MeSH
• receptor erbB-2 MeSH
• receptory pro estrogeny MeSH
• vorinostat MeSH