In an interview with Oncology Learning Network, Poorni Manohar, MD, Senior Fellow, Hematology-Oncology, University of Washington/Fred Hutchinson Cancer Research Center, Seattle Cancer Care Alliance, discussed the promising potential of ¹⁸F-fluoroestradiol (FES) and ¹⁸F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) imaging for detecting metastatic lobular breast cancer, especially with bone involvement.

What existing data led you and your co-investigators to conduct this research?

We presented a poster at the San Antonio Breast Cancer Symposium (SABCS) in 2018 showing that ¹⁸F-Fluoroestradiol (FES) positron-emission tomography (PET) can pick up lobular breast cancer, which has been notoriously difficult to find with conventional imaging. FES-PET picks up estrogen and can be used to measure tumor estrogen expression throughout the body and can predict response to endocrine therapy. 

This year, we looked at bone metastases because it also hard to detect and found that both FES and ¹⁸F-Fluorodeoxyglucose (FDG) lit up with bone and bone marrow uptake. 

Please briefly describe your study and its findings.

We found that the FES scan lit up significantly more in patients with more bone marrow uptake. One interesting result was that patients with bone marrow uptake compared with those without bone marrow uptake had a longer progression free survival (1.3 years vs 0.57 years, respectively). This challenges the conventional belief that bone marrow involvement is an aggressive feature.

The study provides such insight into the biology and spread of lobular breast cancer.

What are the possible real-world applications of these findings in clinical practice?

The takeaway from this study is that FES has a promising role in the detection of metastatic lobular breast cancer, especially with bone involvement. 

FES-PET has been approved and is available in Europe; we are expecting it may be commercially available in the United States as soon as summer 2020. We hope that when it is available for clinical use, we can apply this imaging technique to identify lobular breast cancer in metastatic disease.

Do you and your co-investigators intend to expand upon this research?

We hope to expand the use of FES-PET to early stage of lobular breast cancer. In the current landscape, lobular breast cancer can often be challenging to find with conventional imaging and leads to unnecessary procedures and surgeries due to inaccurate staging.

We hope to perform a clinical trial evaluating the utility of FES-PET to accurately stage lobular breast cancer, and to combine a cost-effectiveness component to the trial to understand the financial and quality of life implications of this novel imaging technique before it is approved. Inclusion of cost effectiveness analysis in prospective trials should be done universally.  

Is there anything else pertaining to your research and findings that you would like to add?

Before, FES-PET is used in clinical practice, we must look into the value of FES-PET. This is an essential step to protect our patients and society from the burden of the rising costs in cancer care.

We presented a poster at SABCS 2019 regarding this topic. Using mathematical modeling and a hypothetical cohort of breast cancer survivors aged 60 years with suspected metastatic breast cancer, we found FES-PET to be a potentially high-value strategy. Our study also found that FES-PET could be cost effective depending on the treatment selection.

The definitive way to understand the financial implications of novel imaging before it is approved is to include a cost-effectiveness analysis as part of prospective trials.