History
An approximately 65-year-old female underwent routine mammography in which suspicious masses were detected at the 3-o’clock position of the left breast. Widespread suspicious calcifications were noted with a recommendation to biopsy for possible metastatic disease (Figure 1). Ultrasound-guided, left breast biopsy performed based on suspicious findings of the mammogram as well as the left axillary lymph node revealed left inflammatory breast cancer, which was identified as a grade 3 invasive ductal carcinoma (Figure 2). 18F-FES PET/CT was ordered due to suspicion of metastatic disease.
Figure 1: Routine mammography shows widespread suspicious masses at the 3-o’clock position of the left breast.
Findings
Approximately 1 hour following 6.2 mCi (229 MBq) intravenous (IV) administration of Cerianna™ (Fluoroestradiol F18) injection[a] a PET imaging agent for use in recurrent or metastatic ER-positive breast cancer as an adjunct to biopsy—the patient was scanned on Biograph Vision™ PET/CT. A PET study using a step-and-shoot method acquisition protocol was performed after an initial CT for attenuation correction. PET images were acquired from the skull vertex to the mid-thigh and were acquired at 9 bed positions at 3 minutes per bed, resulting in a 27-minute total scan time, and then reconstructed with a 440 x 440 matrix.
As seen in Figure 3, 18F-FES PET images reveal multifocal estrogen-receptor (ER)-positive lesions within the left breast, multiple enlarged left axillary lymph nodes, and a solitary enlarged left internal mammary lymph node. Based on the 18F-FES PET/CT findings, the patient underwent anti-androgen therapy, along with chemotherapy agents, which included cyclophosphamide and doxorubicin. The patient was switched from doxorubicin to paclitaxel after approximately 1 month.
A 4-month follow-up 18F-FDG PET/CT scan was ordered for subsequent treatment strategy (STS) decision to assess therapy response and detect the presence of residual disease.
Figure 4: 18F-FDG PET MIP and axial and sagittal PET and CT views at the 4-month follow-up show near-normal 18F-FDG uptake in the area of the previously detected breast and nodal lesions along with decreased soft-tissue nodularity of the left breast, marked interval decrease in size of left axillary/retropectoral lymphadenopathy, and interval resolution of a mildly enlarged left internal mammary chain lymph node.
At the 4-month follow-up scan, the patient received 10.2 mCi (377 MBq) IV administration of Fludeoxyglucose
F 18 (18F-FDG) Injection approximately 47 minutes prior to undergoing PET/CT on Biograph Vision. A skull base to mid-thigh (SBMT) PET study using a step-and-shoot method acquisition protocol was performed after an initial CT for attenuation correction. The SBMT PET study was acquired at 7 bed positions at 2 minutes per bed, resulting in a 14-minute total scan time, and then reconstructed with a 440 x 440 matrix. 18F-FDG PET images shown in Figure 4 show near-normal 18F-FDG uptake in the
area of the previously detected
breast and nodal lesions along
with decreased soft-tissue nodularity
of the left breast, marked interval
decrease in size of left axillary/retropectoral lymphadenopathy, and
interval resolution of a mildly
enlarged left internal mammary
chain lymph node.
The absence of significant hypermetabolism and gross reduction in lesion size as shown by follow-up 18F-FDG PET/CT study suggests a positive response to antiandrogen and adjunct therapies, which were administered based on identification of ER-positive lesions by 18F-FES PET/CT.
Discussion
According to the American Cancer Society, breast cancer is the second-leading cause of cancer death in women after lung cancer and is the most common cancer diagnosed among women in the US, excluding skin cancers. Over 75% of primary breast cancers are hormone-receptor positive. DeSantis et al indicates that the incidence rates of hormone-receptor positive breast cancer are on the rise in the US. This may be due to the increasing prevalence of excess body weight as well as declining fertility rates.1
The utility of PET/CT-directed management of ER-positive primary tumors is essential as patients with distant metastatic disease are rarely cured but often live with disease for years. Therefore, more targeted approaches for early detection strategies are needed in long-term survival care planning.
Conclusion
Endocrine therapies allow a more favorable response in the treatment of patients with distant metastatic breast cancer from an ER-positive primary tumor with fewer side effects. Therefore, 18F-FES PET/CT could prove advantageous in non-invasively assessing ER+ disease, assisting clinicians in making informed treatment decisions, and could be cost-effective for patients considering combinations of endocrine therapy and other targeted agents.2
Examination protocol
Scanner: Biograph Vision 450 PET/CT
Prescribing information
Please see Indications and Important Safety Information.
