Response Monitoring in Metastatic Breast Cancer: A Prospective Study Comparing¹⁸F-FDG PET/CT with Conventional CT

Abstract

This study aimed to compare contrast-enhanced CT (CE-CT) and 18 F-FDG PET/CT for response monitoring in metastatic breast cancer using the standardized response evaluation criteria RECIST 1.1 and PERCIST. The objective was to examine whether progressive disease was detected systematically earlier by one of the modalities. Methods: Women with biopsy-verified metastatic breast cancer were enrolled prospectively and monitored using combined CE-CT and 18 F-FDG PET/CT every 9-12 wk to evaluate response to first-line treatment. CE-CT scans and RECIST 1.1 were used for clinical decision-making without accessing the 18 F-FDG PET/CT scans. At study completion, 18 F-FDG PET/CT scans were unmasked and assessed according to PERCIST. Visual assessment was used if response criteria could not be applied. The modality-specific time to progression was defined as the time from the baseline scan until the first scan demonstrating progression. Paired comparative analyses for CE-CT versus 18 F-FDG PET/CT were applied, and the primary endpoint was earlier detection of progression by one modality. Secondary endpoints were time to detection of progression, response categorization, visualization of changes in response over time, and measurable disease according to RECIST and PERCIST. Results: In total, 87 women were evaluable, with a median of 6 (1-11) follow-up scans. Progression was detected first by 18 F-FDG PET/CT in 43 (49.4%) of 87 patients and first by CE-CT in 1 (1.15%) of 87 patients (P , 0.0001). Excluding patients without progression (n 5 32), progression was seen first on 18 F-FDG PET/CT in 78.2% (43/55) of patients. The median time from detection of progression by 18 F-FDG PET/CT to that of CE-CT was 6 mo (95% CI, 4.3-6.4 mo). At baseline, 76 (87.4%) of 87 patients had measurable disease according to PERCIST and 51 (58.6%) of 87 patients had measurable disease according to RECIST 1.1. Moreover, 18 F-FDG PET/CT provided improved visualization of changes in response over time, as seen in the graphical abstract. Conclusion: Disease progression was detected earlier by 18 F-FDG PET/CT than by CE-CT in most patients, with a potentially clinically relevant median 6-mo delay for CE-CT. More patients had measurable disease according to PERCIST than according to RECIST 1.1. The magnitude of the final benefit for patients is a perspective for future research.

2-[18F]FDG-PET/CT is a better predictor of survival than conventional CT: a prospective study of response monitoring in metastatic breast cancer

“…2-[ 18 F]FDG-PET/CT and the corresponding PET response criteria in solid tumors (PERCIST) have shown to be feasible for response monitoring in women with MBC 7 , 11 and to correlate better with survival than RECIST 1.1 9 , 12 . In a recent head-to-head comparison in our group, PERCIST revealed higher response rates than RECIST 1.1 and classified more patients with measurable disease, indicating important implications for clinical trials 9 , 13 . Furthermore, progression seems to be detected earlier by 2-[ 18 F]FDG-PET/CT than CE-CT, allowing earlier treatment alterations and a potential survival benefit for patients with MBC 13 , 14 .…”

“…In a recent head-to-head comparison in our group, PERCIST revealed higher response rates than RECIST 1.1 and classified more patients with measurable disease, indicating important implications for clinical trials 9 , 13 . Furthermore, progression seems to be detected earlier by 2-[ 18 F]FDG-PET/CT than CE-CT, allowing earlier treatment alterations and a potential survival benefit for patients with MBC 13 , 14 .…”

“…Patients were identified from a previously reported study population from which data on time-related detection of progression, measurable disease, and distribution of response categories have been published separately 13 . The study was registered at Clinical.Trials.gov (NCT03358589), and the results were reported using the STROBE guideline 15 .…”

Comparison of Image Quality and Quantification Parameters between Q.Clear and OSEM Reconstruction Methods on FDG-PET/CT Images in Patients with Metastatic Breast Cancer

“…The clinical and histopathological information of included patients is summarized in Table 2 . More detailed information of included patients is available in a previous publication [ 24 ].…”

“…Inclusion criteria for NCT03358589 were biopsy-verified relapsed or de novo metastatic breast cancer (biopsy verification of primary tumor and disseminated disease at baseline scan), imaging performed on PET/CT scanners with digital technology, and available clinico-histopathological data. Exclusion criteria were age less than 18 years and patients in treatment for other invasive cancers [ 24 ].…”