Paradoxal metabolic flare detected by 18F-fluorodeoxyglucose positron emission tomography in a patient with metastatic breast cancer treated with aromatase inhibitor and biphosphonate
Here we report a case of a 53-year-old woman suffering from advanced breast cancer with bone pain, who came to our observation for the first time in July 2010 in Cracow branch of MSC Memorial Cancer Center. Routine radiological and scintigraphic bone examination confirmed multifocal bone spread with a mixed osteolytic-osteosclerotic pattern [].\nBiphosphonate (Aredia 90 mg/4 weeks) and endocrine treatments were immediately started (Zoladex 3.6 mg/month and Tamoxifen 20 mg/day) together with palliative radiotherapy of left hemipelvis.\nThe first FDG PET scan was ruled out in Gliwice branch of our institution on October 1, 2010 in order to exclude metastatic spread to soft-tissues. It was performed with the use of a Philips Gemini GXL device, 60 min after an injection of 333 MBq of radiotracer. Numerous skeletal lesions were detected, with no metastases outside bones [].\nA bone scan showed progression in April 2011. Due to clinical worsening of the patient's condition, with Zubrod score having increased from 2 to 3, Tamoxifen was substituted with an aromatase inhibitor (Femara 2.5 mg/day). The second palliative radiotherapy was performed on the thoracic spine from April to May 2011.\nA clinical improvement was observed successively in September 2011, with Zubrod score having returned to 2 and a stable bone scan.\nIn March 2012, Zubrod score shifted down further to 1 and Zoladex were stopped. The patient got only bifosphonate and aromatase inhibitor treatment.\nAnother FDG PET examination was performed on February 8, 2013 for a complexive evaluation of the regression degree, 22 and 31 months after the beginning of therapies with the aromatase inhibitor and biphosphonate respectively. The scan was ruled out with the use of a Siemens mCT device, 1 h after an injection of 240 MBq of FDG. Evident recalcification of bone lesions was seen on computed tomography (CT), while an increase of FDG uptake was clearly observable for almost all the bone lesions [Figures , and ]. A direct comparison between SUV scores was not possible, because of PET scans having been performed by different devices. However, tumor/background ratios between physiological liver uptake and pathologic FDG accumulation displayed on Figures (V right rib) and (sternum) confirmed the visual impression of increased radiofarmaceutical uptake [].