Prospective Clinical Trial of (18)F-Fluciclovine PET/CT for Determining the Response to Neoadjuvant Therapy in Invasive Ductal and Invasive Lobular Breast Cancers.

18F-labeled 1-amino-3-fluorocyclobutane-1-carboxylic acid (18F-fluciclovine) is a leucine analog radiotracer that depicts amino acid transport into cells. 18F-fluciclovine PET/CT visualizes malignancy, including prostate cancer, invasive ductal breast cancer, and invasive lobular breast cancer. Whether changes in 18F-fluciclovine avidity reflect changes in tumor burden resulting from treatment has not been shown. In this prospective clinical trial (clinical trials.gov: NCT01864083), changes in 18F-fluciclovine avidity after neoadjuvant therapy were compared to breast cancer therapy response, as determined by residual tumor burden on pathology, were evaluated. Methods: Twenty-four women with a new diagnosis of locally advanced invasive ductal breast cancer (n = 18) or invasive lobular breast cancer (n = 6) underwent 18F-fluciclovine PET/CT before and after the completion of neoadjuvant systemic therapy. SUVmax, SUVmean, metabolic tumor volume, and total lesion avidity were obtained for the primary breast tumor, axillary lymph nodes, and extraaxillary lymph nodes on each examination and corrected for background 18F-fluciclovine avidity. The relationship between changes in 18F-fluciclovine avidity and the percentage of reduction of tumor on pathology was assessed with the Spearman rank correlation. Results: The median decrease in the corrected SUVmax of the primary breast lesions was 99% (range, 33%-100%). The median reduction of tumor on pathology was 92% (range, 10%-100%). Changes in 18F-fluciclovine avidity were strongly correlated with the percentage of reduction of tumor on pathology (Spearman ρ, 0.79; 95% CI, 0.56-0.90; P < 0.001). Conclusion: Changes in 18F-fluciclovine avidity strongly correlated with the tumor response on pathology in this pilot study.

Ulaner GA ，Goldman DA ，Corben A ，Lyashchenko SK ，Gönen M ，Lewis JS ，Dickler M ... -  《-》

Initial Results of a Prospective Clinical Trial of 18F-Fluciclovine PET/CT in Newly Diagnosed Invasive Ductal and Invasive Lobular Breast Cancers.

(18)F-labeled 1-amino-3-fluorocyclobutane-1-carboxylic acid ((18)F-fluciclovine) is a leucine analog PET/CT radiotracer that depicts amino acid transport into cells. Amino acid transport proteins have been shown to be upregulated in breast malignancies by microarray and immunohistochemical analysis, so we hypothesized that (18)F-fluciclovine may provide a novel method of visualizing breast cancer and now report a prospective clinical trial of (18)F-fluciclovine PET/CT in newly diagnosed advanced local invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC). Twenty-seven women with a new diagnosis of locally advanced IDC (n = 19) or ILC (n = 8) underwent PET/CT of the chest after intravenous administration of 370 MBq of (18)F-fluciclovine. The SUVmax, SUVmean, metabolic tumor volume, and total lesion avidity were obtained for the primary breast tumor, axillary lymph nodes, and extraaxillary lymph nodes. Sites of previously unsuspected malignancy were recorded and confirmed by pathology. Results of (18)F-fluciclovine PET/CT were compared with those of (18)F-FDG PET/CT, when available, using the concordance correlation coefficient. All locally advanced breast cancers were (18)F-fluciclovine-avid. Of 21 patients with pathologically proven axillary nodal metastases, (18)F-fluciclovine-avid axillary nodes were seen in 20. (18)F-fluciclovine detected pathologically proven extraaxillary nodal metastases in 3 patients, including 2 previously unsuspected internal mammary nodes. Fourteen patients underwent (18)F-FDG PET/CT for comparison with (18)F-fluciclovine. Concordance for metabolic tumor volume between (18)F-fluciclovine and (18)F-FDG was strong (concordance correlation coefficient, 0.89; 95% confidence interval, 0.73-0.96), but concordance for SUVmax was weak (concordance correlation coefficient, 0.04; 95% confidence interval, -0.16-0.24). In patients with both modalities available (n = 14), primary ILCs (n = 4) demonstrated (18)F-fluciclovine avidity (median SUVmax, 6.1; range, 4.5-10.9) greater than (18)F-FDG avidity (median SUVmax, 3.7; range, 1.8-6.0). Primary IDCs (n = 10) had a lower (18)F-fluciclovine avidity (median SUVmax, 6.8; range, 3.6-9.9) than (18)F-FDG avidity (median SUVmax, 10; range, 3.3-43.5). (18)F-fluciclovine PET/CT demonstrates potential for imaging of both IDC and ILC, including the detection of unsuspected extraaxillary nodal metastases. The low concordance for SUVmax between (18)F-fluciclovine and (18)F-FDG suggests that these tracers measure different biologic phenomena within the tumor. The apparently higher uptake of (18)F-fluciclovine in ILC requires confirmation in a larger cohort.

Ulaner GA ，Goldman DA ，Gönen M ，Pham H ，Castillo R ，Lyashchenko SK ，Lewis JS ，Dang C ... -  《-》

Anti-3-18F-FACBC (18F-Fluciclovine) PET/CT of Breast Cancer: An Exploratory Study.

The purpose of this study was to explore the uptake of the synthetic amino acid analog PET radiotracer anti-3-(18)F-FACBC ((18)F-fluciclovine) in breast lesions with correlation to histologic and immunohistochemical characteristics. Twelve women with breast lesions underwent 45-min dynamic PET/CT of the thorax after intravenous administration of 366.3 ± 14.8 (337.44-394.05) MBq of (18)F-fluciclovine. Uptake in the primary lesions at 4 representative time points (5, 17, 29, and 41 min) after injection were correlated with histologic, imaging, and clinical findings. The significance of differences in SUVmax and tumor-to-background ratios between malignant and benign tissue were calculated. Correlations of activity to histologic and immunohistochemical cancer subtypes were made including Ki-67 intensity and Nottingham grade (NG). There were 17 breast lesions (4 benign, 13 malignant) including 7 of 13 invasive ductal, 5 of 13 invasive lobular, and 1 of 13 metaplastic carcinomas. There was a significant difference in mean SUVmax ± SD of malignant (6.2 ± 3.2, 6.0 ± 3.2, 5.7 ± 2.8, and 5.6 ± 3.0) versus benign (1.3 ± 0.6, 1.2 ± 0.5, 1.2 ± 0.6, and 1.1 ± 0.5) lesions at 5, 17, 29, and 41 min, respectively (all P ≤ 0.0001). Tumor-to-background (aorta, normal breast, and marrow) ratios were also significantly higher in malignant than benign breast lesions (all P ≤ 0.02). The highest (18)F-fluciclovine activity seems to be present in triple-negative and NG3 subtypes. Across time points, quantitative Ki-67 had weak positive correlation with SUVmax (R1 = 0.48 [P = 0.03], R2 = 0.44 [P = 0.03], R3 = 0.46 [P = 0.03], R4 = 0.43 [0.06]). In 7 patients, (18)F-fluciclovine PET visualized locoregional and distant spread including that of lobular cancer, though identification of hepatic metastases was limited by physiologic background activity. The uptake characteristics of (18)F-fluciclovine are reflective of the histologic and immunohistochemical characteristics in suspected breast lesions with greater activity in malignant versus benign etiology. The data from this exploratory study may be useful to design future studies using (18)F-fluciclovine PET for breast tumor imaging as well as for detection of locoregional and distant spread.

Tade FI ，Cohen MA ，Styblo TM ，Odewole OA ，Holbrook AI ，Newell MS ，Savir-Baruch B ，Li X ，Goodman MM ，Nye JA ，Schuster DM ... -  《-》

More advantages in detecting bone and soft tissue metastases from prostate cancer using (18)F-PSMA PET/CT.

Pianou NK ，Stavrou PZ ，Vlontzou E ，Rondogianni P ，Exarhos DN ，Datseris IE ... -  《Hellenic Journal of Nuclear Medicine》

Image Guided Planning for Prostate Carcinomas With Incorporation of Anti-3-[18F]FACBC (Fluciclovine) Positron Emission Tomography: Workflow and Initial Findings From a Randomized Trial.

(18)F-Fluciclovine (anti-1-amino-3-[(18)F]fluorocyclobutane-1-carboxylic acid) is a novel positron emission tomography (PET)/computed tomography (CT) radiotracer that has demonstrated utility for detection of prostate cancer. Our goal is to report the initial results from a randomized controlled trial of the integration of (18)F-fluciclovine PET-CT into treatment planning for defining prostate bed and lymph node target volumes. We report our initial findings from a cohort of 41 patients, of the first enrolled on a randomized controlled trial, who were randomized to the (18)F-fluciclovine arm. All patients underwent (18)F-fluciclovine PET-CT for the detection of metabolic abnormalities and high-resolution CT for treatment planning. The 2 datasets were registered first by use of a rigid registration. If soft tissue displacement was observable, the rigid registration was improved with a deformable registration. Each (18)F-fluciclovine abnormality was segmented as a percentage of the maximum standard uptake value (SUV) within a small region of interest around the lesion. The percentage best describing the SUV falloff was integrated in planning by expanding standard target volumes with the PET abnormality. In 21 of 55 abnormalities, a deformable registration was needed to map the (18)F-fluciclovine activity into the simulation CT. The most selected percentage was 50% of maximum SUV, although values ranging from 15% to 70% were used for specific patients, illustrating the need for a per-patient selection of a threshold SUV value. The inclusion of (18)F-fluciclovine changed the planning volumes for 46 abnormalities (83%) of the total 55, with 28 (51%) located in the lymph nodes, 11 (20%) in the prostate bed, 10 (18%) in the prostate, and 6 (11%) in the seminal vesicles. Only 9 PET abnormalities were fully contained in the standard target volumes based on the CT-based segmentations and did not necessitate expansion. The use of (18)F-fluciclovine in postprostatectomy radiation therapy planning was feasible and led to augmentation of the target volumes in the majority (30 of 41) of the patients studied.

Schreibmann E ，Schuster DM ，Rossi PJ ，Shelton J ，Cooper S ，Jani AB ... -  《-》