Impact of 18F-Labeled Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Versus Conventional Staging in Patients With Locally Advanced Breast Cancer

Author(s): Ian S. Dayes, MD, MSc1,2,3,4; Ur Metser, MD5,6; Nicole Hodgson, MD, MSc7; Sameer Parpia, PhD1,3,4; Andrea F. Eisen, MD8,9,10; Ralph George, MD11,12; Phillip Blanchette, MD, MSc13,14; Tulin D. Cil, MD6,11; Angel Arnaout, MD15,16; Adrien Chan, MD, MPH17,18; and Mark N. Levine, MD, MSc1,2,3,4
Source: DOI: 10.1200/JCO.23.00249 Journal of Clinical Oncology 41, no. 23 (August 10, 2023) 3909-3916.
Maem Hussein MD

Dr. Maen Hussein's Thoughts

It seems that PET is better than CT scan in locally advanced disease staging, better in upstaging, and may spare the patient combined modality therapy.

PURPOSE

Patients with locally advanced breast cancer (LABC) typically undergo staging tests at presentation. If staging does not detect metastases, treatment consists of curative intent combined modality therapy (neoadjuvant chemotherapy, surgery, and regional radiation). Positron emission tomography-computed tomography (PET-CT) may detect more asymptomatic distant metastases, but the evidence is based on uncontrolled studies.

METHODS

For inclusion, patients had histological evidence of invasive ductal carcinoma of the breast and TNM stage III or IIb (T3N0, but not T2N1). Consenting patients from six regional cancer centers in Ontario were randomly assigned to 18F-labeled fluorodeoxyglucose PET-CT or conventional staging (bone scan, CT of the chest/abdomen and pelvis). The primary end point was upstaging to stage IV. A key secondary outcome was receiving curative intent combined modality therapy (ClinicalTrials.gov identifier: NCT02751710).

RESULTS

Between December 2016 and April 2022, 184 patients were randomly assigned to whole-body PET-CT and 185 patients to conventional staging. Forty-three (23%) PET-CT patients were upstaged to stage IV compared with 21 (11%) conventional staged patients (absolute difference, 12.3% [95% CI, 3.9 to 19.9]; P = .002). Consequently, treatment was changed in 35 (81.3%) of 43 upstaged PET-CT patients and 20 (95.2%) of the 21 upstaged conventional patients. Subsequently, 149 (81%) patients in the PET-CT group received combined modality treatment versus 165 (89.2%) patients in the conventional staging group (absolute difference, 8.2% [95% CI, 0.1 to 15.4]; P = .03).

CONCLUSION

In patients with LABC, PET-CT detected more distant metastases than conventional staging, and fewer PET-CT patients received combined modality therapy. Our randomized trial demonstrates the utility of the PET-CT staging strategy.

Author Affiliations

1Department of Oncology, McMaster University, Hamilton, ON, Canada;2Juravinski Cancer Centre—Hamilton Health Sciences, Hamilton, ON, Canada;3Ontario Clinical Oncology Group, Hamilton, ON, Canada;4Escarpment Cancer Research Institute, Hamilton, ON, Canada;5Joint Department of Medical Imaging, University of Toronto, Toronto, ON, Canada;6University Health Network Princess Margaret Cancer Centre, Toronto, ON, Canada;7Department of Surgery, McMaster University, Hamilton, ON, Canada;8Department of Medicine, University of Toronto, Toronto, ON, Canada;9Sunnybrook Health Sciences Centre—Odette Cancer Centre, Toronto, ON, Canada;10Ontario Health, Toronto, ON, Canada;11Department of Surgery, University of Toronto, Toronto, ON, Canada;12St Michael’s Hospital, Toronto, ON, Canada;13Department of Oncology, Western University, London, ON, Canada;14London Health Sciences Regional Cancer Program, London, ON, Canada;15Department of Surgery, Ottawa University, Ottawa, ON, Canada;16Ottawa Hospital Cancer Centre, Ottawa, ON, Canada;17Northern Ontario School of Medicine, Thunder Bay ON, Canada;18Thunder Bay Regional Health Sciences Cancer Centre, Thunder Bay, ON, Canada

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