Estrogen Receptor Expression in Breast Cancer - Assessed With Positron Emission Mammography

This pilot study will recruit up to 20 patients with newly diagnosed ER+ breast cancer who
have recently undergone or are scheduled to undergo a clinically-indicated breast MRI
examination and are scheduled for surgical excision of the breast cancer. All patients will
undergo two PEM studies, one with F-18 FDG and the second with F-18 FES. As F-18 FES is not
an FDA-approved radiopharmaceutical, this FES study will be performed under an investigator
IND cross-referenced to the National Cancer Institute IND 79,005 for F-18 FES. A time
interval of 6-8 hours will be required between performance of the F-18 FDG study and the F-18
FES study. All patients will have the 2 PEM studies within 30 business days of the clinically
indicated MRI. See Study Schema shown below. Subjects must meet the following eligibility
criteria:

1. Postmenopausal women, as defined by a. Lack of menstrual periods for ≥ 12 months b. For
women with prior hysterectomy and age < 60, a serum FSH level within the postmenopausal
range

2. Histologic proof of invasive breast carcinoma that is ER positive per ASCO/CAP
guidelines (staining in ≥ 1% of cells by immunohistochemistry)

3. Extent of disease confirmed, or to be confirmed, on a clinical contrast-enhanced breast
MRI examination

4. Minimum size criteria for index cancer of 10 mm as measured on mammogram, ultrasound, or
MRI.

5. Planned surgical excision of the breast cancer at Mayo Clinic, Rochester

Study participants will be consented prior to undergoing the PEM studies. The order in which
the PEM and MRI studies are performed will NOT be randomized, and will be dictated by patient
schedule. Co-registration of the PEM images from F-18 FDG and F-18 FES will be used to assess
the heterogeneity of uptake of the F-18 FES relative to that of F-18 FDG. Heterogeneity of ER
expression in the tumor will be determined by immunohistochemistry on the pathologic tissue
and findings will then be correlated with the ratio of activity in the co-registered images
of F-18 FES and F-18 FDG. An integrated interpretation of the MRI and PEM images will be
performed to match lesions seen on the three scans and will be made available to the ordering
physician and surgeon.

Inclusion Criteria:

Eligible patients will be offered enrollment if the time interval between initial diagnosis
and surgery allows for performance of the PEM studies with both F18 FDG and F-18 FES, and
they meet the following criteria:

- Postmenopausal women, as defined by

- Lack of menstrual periods for ≥ 12 months

- For women with prior hysterectomy and age < 60, a serum FSH level within the
postmenopausal range

- Histologic proof of invasive breast carcinoma that is ER positive per ASCO/CAP
guidelines (staining in ≥ 1% of cells by immunohistochemistry)

- Extent of disease confirmed, or to be confirmed, on a clinical contrast-enhanced
breast MRI examination

- Minimum size criteria for index cancer of 10 mm as measured on mammogram, ultrasound,
or MRI.

- Planned surgical excision of the breast cancer at Mayo Clinic, Rochester

Exclusion Criteria:

Patients are excluded if they meet any of the following criteria:

- Premenopausal

- Unable to undergo PEM scanning (weight limit of 300 lbs. on PEM system or inability to
lie prone for 30 minutes)

- Total serum bilirubin > 1.5 x upper limit of normal (abnormal hepatic metabolism may
interfere with FES hepatic excretion),

- Serum creatinine > 1.5 x upper limit of normal

- Patients who have received, are currently receiving, or planning to receive
neoadjuvant systemic therapy prior to surgical excision

- Patients who will undergo core needle biopsy of the breast or axilla between the
breast MRI and investigational PEM studies. NOTE: Axillary ultrasound with or without
fine needle aspiration of an axillary mass or lymph node is allowed.

- Patients with breast implants?