FDG-PET/CT is accurate in diagnosing breast cancer recurrence
A woman with a substantial risk of breast cancer recurrence experiences worry and anxiety, and a correct diagnosis is relevant in order to make well-founded decision on treatment strategy. It is then crucial to provide accurate diagnostic work-up in such patients with suspected recurrent disease.
Although current guidelines do not recommend imaging other than mammography after primary treatment of breast cancer, diagnostic work-up is recommended when clinically indicated. There have been no clear recommendations about which imaging procedure is best for detecting recurrence.
Conventional diagnostic work-up often includes combined imaging procedures, but a modern stand-alone-procedure may provide more accurate diagnostic information. BS (bone scintigraphy) and CT (computed tomography) are conventional procedures, and FDG-PET/CT is a modern imaging procedure that stands for 18F-fluorodeoxyglucose-positron emission tomography/computed tomography. FDG-PET/CT is a functional imaging procedure that uses radioactively labeled sugar molecules to detect cancer.
We performed a diagnostic study of 100 patients with suspected recurrent breast cancer. FDG-PET/CT was compared to conventional work-up procedures. A comparison was also made for FDG-PET/CT between imaging at one hour and three hours after injection of the radioactive sugar, FDG. Biopsy and clinical follow-up determined whether patients had recurrence or not.
Of 100 women, 22 endured distant recurrence, 19 had local recurrence only, and 59 women experienced no recurrence.
When we obtained a negative test result on FDG-PET/CT, we were able to rule out distant recurrence, since all patients with distant recurrence were detected by FDG-PET/CT. In comparison conventional work-up overlooked distant recurrence in two patients. An example of a patient with bone recurrence who had false negative test results on conventional work-up has been shown in Figure 1.
Seven women were falsely diagnosed with disease recurrence by FDG-PET/CT. In contrast conventional work-up resulted in 22 patients with false positive test results; these were mainly caused by false positive liver lesions on the CT scan and false positive bone lesions on the BS.
FDG-PET/CT proved to be significantly more accurate in diagnosing distant recurrence than conventional work-up as illustrated by AUC-ROC curves in Figure 2. Surprisingly, however, one hour and three hour imaging results of FDG-PET/CT were almost identical.
We conclude that FDG-PET/CT did well in diagnosing breast cancer recurrence and better than conventional work-up. Since FDG-PET/CT serves as a stand-alone-procedure, it may also be advantageous to conventional work-up that requires more than one procedure.
Our study was carried out in a single institution with experience in performing PET since 2006, and caution should be made when generalizing from our results. A synthesis of results from proper diagnostic studies along with economic and organizational assessments is needed before generalized conclusions should be drawn. Furthermore, the patients’ perspective on implementing FDG-PET/CT should also be taken into account.
The Region of Southern Denmark funded this research. The authors made no disclosures.
Malene Grubbe Hildebrandt
Department of Nuclear Medicine, Odense University Hospital, Denmark
[18F]Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET)/Computed Tomography (CT) in Suspected Recurrent Breast Cancer: A Prospective Comparative Study of Dual-Time-Point FDG-PET/CT, Contrast-Enhanced CT, and Bone Scintigraphy.
Hildebrandt MG, Gerke O, Baun C, Falch K, Hansen JA, Farahani ZA, Petersen H, Larsen LB, Duvnjak S, Buskevica I, Bektas S, Søe K, Jylling AM, Ewertz M, Alavi A, Høilund-Carlsen PF
J Clin Oncol. 2016 Jun 1