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, MSc^1,2,3,4; Ur Metser, MD^5,6; Nicole Hodgson, MD, MSc⁷; Sameer Parpia, PhD^1,3,4; Andrea F. Eisen, MD^8,9,10; Ralph George, MD^11,12; Phillip Blanchette, MD, MSc^13,14; Tulin D. Cil, MD^6,11; Angel Arnaout, MD^15,16; Adrien Chan, MD, MPH^17,18; and Mark N. Levine, MD, MSc^1,2,3,4

Source: DOI: 10.1200/JCO.23.00249 Journal of Clinical Oncology 41, no. 23 (August 10, 2023) 3909-3916.

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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There have been studies showing decreased recurrence in women who underwent curative breast surgeries (walking and yoga). This study assesses if it will affect the intensity of chemotherapy delivered. Although it did not affect it, women who underwent the program had better pathologic complete response (pCR), we need more studies to assess role of nutrition and exercise in treating cancer as we develop a wholesome approach to treat our patients, something we may be able to do in our practice.

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This is a 10-year follow-up of the ShortHER study using nine weeks vs. 12 months of adjuvant trastuzumab in HR+ non-metastatic breast cancer. With long-term follow-up, non-inferiority could not be claimed statistically. Still, the DFS/OS results are identical in those patients with N0-N3 disease, while those with N4 disease seemed to have a significant difference favoring 12 months of therapy, suggesting that volume/burden of disease drives the margin of benefit in adjuvant trastuzumab therapy.