By Will Boggs MD
NEW YORK (Reuters Health) - 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is accurate in diagnosing recurrence in women with suspected recurrent breast cancer, according to results of a study in Denmark.
"FDG-PET/CT did very well and also better than conventional imaging (contrast enhanced CT and bone scintigraphy) in diagnosing breast cancer recurrence," Dr. Malene Grubbe Hildebrandt from Odense University Hospital told Reuters Health by email. "Surprisingly, we found no difference in patient-based diagnostic accuracy between one hour and three hour imaging of FDG-PET/CT."
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 modality is best for detecting recurrence.
Dr. Hildebrandt's team investigated the diagnostic accuracy of dual-time-point FDG-PET/CT versus contrast-enhanced CT (ceCT) and bone scintigraphy (BS) in a prospective study of 100 women with suspected recurrent breast cancer.
Twenty-two women were diagnosed with distant recurrence -- five with metastases in one distant site, eight with metastases in two sites, and nine with metastases in three or more sites, according to the March 21 Journal of Clinical Oncology online report.
Nineteen women had local occurrence only, and 59 had no recurrence.
Based on AUC-ROC curves, FDG-PET/CT was more accurate than ceCT and BS in the diagnosis of distant, bone, and local recurrence. Its sensitivity was significantly higher, and its specificity was nonsignificantly higher than that of ceCT and BS combined.
Seven women were falsely diagnosed with disease recurrence by FDG-PET/CT. In contrast, ceCT resulted in 18 false test results. Adding BS to ceCT resulted in correct reclassification of 3 of 4 false-negative bone lesions, but also identified 10 new false-positive bone lesions and still failed to detect 2 metastatic lesions.
"Our study has been performed in a single institution with experience in performing PET since 2006, and we should be cautious when generalizing from our results," Dr. Hildebrandt said. "I think that a synthesis of literature, preferably based on more prospective studies in this field, is needed along with health economic assessments before more generalizing conclusions should be drawn."
"I would like to make a point of considering the patients' perspective and the economic consequences of implementing FDG-PET/CT in this patient group," she added. "We will continue doing analyses of the patients' perspective of having only one as compared to two diagnostic tests performed, and also of organizational and economic consequences of implementing FDG-PET/CT in this setting."
Dr. Rodney J. Hicks, from Peter MacCallum Cancer Centre, East Melbourne, Australia, who has published several studies of FDG-PET/CT for recurrent breast cancer, told Reuters Health by email, "FDG PET/CT should have long ago replaced CT and bone scan for the primary staging of locally advanced breast cancer, assessment of therapeutic response to chemotherapy in patients with metastatic disease, and for evaluating suspected recurrence if it weren't for reimbursement issues."
"It takes at least two decades for new technologies to be embraced and used appropriately by clinicians and maybe longer to get rational reimbursement policies," Dr. Hicks said. "The continual push and pull of the believers in the technology against the 'we will not pay without ever stronger evidence' authorities has damaged patients through perpetuating practices that lead to inaccurate diagnosis."
"Women have been very strong and effective advocates for access to therapies that sometimes make a rather small impact on breast cancer outcomes," he concluded. "They need to use their voices to demand wider access to accurate diagnosis before expensive, mutilating or toxic therapies are applied."
Dr. Lino M. Sawicki, from the University of Duesseldorf in Germany, who recently compared various imaging modalities for staging recurrent breast cancer, told Reuters Health by email, "Over the last years, multiple studies have shown the superiority of PET/CT over conventional imaging modalities in cancer staging of a variety of cancer entities. The possibility of combining the high anatomical and spatial resolution of CT with functional tissue information about glucose metabolism has already proven superior for breast cancer recurrence."
"PET/CT is a highly sensitive and specific diagnostic tool both for the detection of local and distant relapse in patients with suspected breast cancer," Dr. Sawicki concluded. "Physicians should consider PET/CT over conventional imaging for staging patients with suspected breast cancer recurrence."
The Region of Southern Denmark funded this research. The authors made no disclosures.
J Clin Oncol 2016.
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