PT - JOURNAL ARTICLE AU - Jie Zang AU - Feng Mao AU - Hao Wang AU - Qingxing Liu AU - Zhaohui Zhu AU - Xiaoyuan Chen TI - <sup>68</sup>Ga-NOTA-RM26 PET/CT in the Evaluation of Breast Cancer: A Pilot Prospective Study DP - 2018 May 01 TA - Journal of Nuclear Medicine PG - 489--489 VI - 59 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/59/supplement_1/489.short 4100 - http://jnm.snmjournals.org/content/59/supplement_1/489.full SO - J Nucl Med2018 May 01; 59 AB - 489Purpose: This prospective pilot study investigated the use of 68Ga-NOTA-RM26, an antagonist targeting gastrin-releasing peptide receptor (GRPR), for evaluating breast cancer using positron-emission tomography/computed tomography (PET/CT). Methods: With institutional review board approval and informed consent, twenty female patients suspected of having breast cancer based on mammography or ultrasonography were recruited. Within 1 week before surgery,patients underwent whole-body PET/CT scans at 30 minutes after intravenous injection of 1.85 MBq per kilogram body weight of 68Ga-NOTA-RM26. Nineteen patients were pathologically diagnosed with breast cancer and the remaining patient was found to have a fibrous tumor. Among the breast cancer patients, 10 cases had ipsilateral lymph node metastasis. Results: No remarkable adverse event that correlated with the study was reported. 68Ga-NOTA-RM26 PET/CT delineated the primary tumor well in 14/19 (74%) patients, and the lymph node metastasis in 7/10 (70%) of the patients, whereas the other 3 patients demonstrated only micro-metastasis in lymph nodes. The maximum standardized uptake values (SUVmax) were 2.66 ± 1.02 in the breast cancer, and 1.07 in the fibrous tumor. The SUVmax of estrogen receptor (ER)-positive tumors were higher than those in ER-negative tumors. The normal breast tissue (NBT) showed low to moderate 68Ga-RM26 binding, with a SUVmax of 1.19 ± 0.50 and a SUVmean of 0.85 ± 0.38. The intensity of 68Ga-RM26 uptake in the NBT was significantly associated with menstrual cycle (P = 0.003). Normal physical RM26 uptake in the secretory phases was significantly higher than those in the nonsecretory phases (P = 0.02) and menopause (P = 0.007). When a SUVmax of 68Ga-RM26 1.775 was used as a cutoff for differentiating breast cancer and NBT, the resulting sensitivity, specificity, and accuracy were 89.5%, 81.0%, and 85.3%, respectively. There was a significant positive correlation between the SUVmax of 68Ga-RM26 and the GRPR expression level (r = 0.817, P = 0.001). Conclusions: This pilot study indicated that the uptake of gastrin-releasing peptide receptor antagonist 68Ga-NOTA-RM26 may correlate with ER expression in breast cancer. To avoid the physiological uptake of 68Ga-NOTA-RM26 in normal breast tissue, it is suggested that this examination not be performed during the secretory phase of the menstrual cycle. Figure legend: Figure 1. A 60-year-old patient with breast invasive ductal carcinoma showed intense 68Ga-RM26 uptake in the primary tumor (blue arrows) and lymph node metastasis (yellow arrows) on the left side. The tumor stained positively for ER (F) and GRPR (G); the lymph node also stained positively for GRPR (H). Figure 2. The SUVmax of ER-positive tumors (2.95 ± 0.93) were significantly higher than those of ER-negative tumors (1.42 ± 0.36, P = 0.013) (I). The SUVmax as determined by 68Ga-RM26 PET correlated well with the GRPR expression level in breast cancer and lymph nodes (r = 0.817, P = 0.001) (J). The SUVmax of normal breast tissue were significantly higher in the secretory phases as compared with those in the nonsecretory phases (P = 0.02) and menopause (P = 0.007) (K).