BREAST CANCER. INCIDENCE OF NEW LESIONS DETECTED BY HIGH RESOLUTION BREAST PET WITH 18F-FDG NOT SEEN ON THE MAMMOGRAPHY

Introduction: The American College of Radiology recommended the breast mammography as the standard method in breast cancer screening, nevertheless the incidence of breast cancer has not changed significantly in the last 10 years, despite constant awareness campaigns for women to have their mammography. The success of any screening program depends on the detection of small lesions.

High Resolution Breast PET can detect lesions measuring less than five millimeters, it is not affected by breast density or the hormonal status.

The sensitivity for High Resolution Breast PET is similar than breast MRI, but with higher specificity (92-97% vs 85-92%).

In breast cancer the metabolism of 18F-FDG is higher in malignant cells with increased uptake of the radiotracer when compared to normal tissues.

It is possible to fuse the images from the Mammography with the Breast PET using a special software.

Methods: This retrospective study was approved by the ethics committee. Patients with previous breast cancer, mother or sister with history of cancer (high risk patients) and patients with lesions in the mammography were enrolled. The inclusion criteria were patients with at least one mammography. The exclusion criteria were patients who did not have a High Resolution Breast PET. We reviewed the clinical reports of both studies from 2016 to 2019. The mammograms were read by a board certified radiologist with added qualification in breast. The Breast PET´s were read by a board certified nuclear medicine physician. The fusion of both images was performed.

Results: A total of 422 patients were included, with breast density pattern type A in 13%, type B in 62%, type C in 18% and type D in 7%. The lesions showed a concordant correlation between mammography and Breast PET in patients with breast density pattern type A and B. In patients with breast density pattern type C 23 % lesions seen on the Breast PET were not seen on the mammography and 31% of lesions in patients with breast density pattern type D.

Conclusions: High Resolution Breast PET with 18F-FDG detected 23% of malignant lesions not seen on the mammography in patients with breast density pattern type C.

High Resolution Breast PET with 18F-FDG detected 31% of malignant lesions not seen on the mammography in patients with breast density pattern type D.

High Resolution Breast PET with 18F-FDG plays an important role in clinical decision making in patients with dense breast.