RT Journal Article
SR Electronic
T1 Breast Cancer <sup>18</sup>F-ISO-1 Uptake as a Marker of Proliferation Status
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 665
OP 670
DO 10.2967/jnumed.119.232363
VO 61
IS 5
A1 McDonald, Elizabeth S.
A1 Doot, Robert K.
A1 Young, Anthony J.
A1 Schubert, Erin K.
A1 Tchou, Julia
A1 Pryma, Daniel A.
A1 Farwell, Michael D.
A1 Nayak, Anupma
A1 Ziober, Amy
A1 Feldman, Michael D.
A1 DeMichele, Angela
A1 Clark, Amy S.
A1 Shah, Payal D.
A1 Lee, Hsiaoju
A1 Carlin, Sean D.
A1 Mach, Robert H.
A1 Mankoff, David A.
YR 2020
UL http://jnm.snmjournals.org/content/61/5/665.abstract
AB The σ2 receptor is a potential in vivo target for measuring proliferative status in cancer. The feasibility of using N-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-2-(2-18F-fluoroethoxy)-5-methylbenzamide (18F-ISO-1) to image solid tumors in lymphoma, breast cancer, and head and neck cancer has been previously established. Here, we report the results of the first dedicated clinical trial of 18F-ISO-1 in women with primary breast cancer. Our study objective was to determine whether 18F-ISO-1 PET could provide an in vivo measure of tumor proliferative status, and we hypothesized that uptake would correlate with a tissue-based assay of proliferation, namely Ki-67 expression. Methods: Twenty-eight women with 29 primary invasive breast cancers were prospectively enrolled in a clinical trial (NCT 02284919) between March 2015 and January 2017. Each received an injection of 278–527 MBq of 18F-ISO-1 and then underwent PET/CT imaging of the breasts 50–55 min later. In vivo uptake of 18F-ISO-1 was quantitated by SUVmax and distribution volume ratios and was compared with ex vivo immunohistochemistry for Ki-67. Wilcoxon rank-sum tests assessed uptake differences across Ki-67 thresholds, and Spearman correlation tested associations between uptake and Ki-67. Results: Tumor SUVmax (median, 2.0 g/mL; range, 1.3–3.3 g/mL), partial-volume–corrected SUVmax, and SUV ratios were tested against Ki-67. Tumors stratified into the high–Ki-67 (≥20%) group had SUVmax greater than the low–Ki-67 (&lt;20%) group (P = 0.02). SUVmax exhibited a positive correlation with Ki-67 across all breast cancer subtypes (ρ = 0.46, P = 0.01, n = 29). Partial-volume–corrected SUVmax was positively correlated with Ki-67 for invasive ductal carcinoma (ρ = 0.51, P = 0.02, n = 21). Tumor–to–normal-tissue ratios and tumor distribution volume ratio did not correlate with Ki-67 (P &gt; 0.05). Conclusion: 18F-ISO-1 uptake in breast cancer modestly correlates with an in vitro assay of proliferation.