Limited clinical value of routine PET/CT in early-stage breast cancer: a multicenter retrospective study

Staging of breast cancer at diagnosis is essential for prognosis and guiding treatment decisions. The role of ^18F-FDG positron emission tomography/computed tomography (PET/CT) in patients with asymptomatic early-stage breast cancer remains controversial because of the low prevalence of distant metastasis and risk of false-positive findings.

This is a retrospective multicenter cohort study across three tertiary centers in Lebanon. Adult patients with newly diagnosed stage I or IIA breast cancer who underwent PET/CT for initial staging between January 2019 and December 2024 were included. Patients receiving neoadjuvant therapy prior to imaging or with more advanced disease were excluded. Descriptive statistics were used to summarize outcomes, including rates of disease upstaging and false-positive findings.

A total of 435 patients were included. Most tumors were invasive ductal carcinoma (88.0%) and hormone receptor-positive (ER 88.5%, PR 81.4%), with HER2 positivity in 17.7%. PET/CT resulted in stage upstaging in 23 patients (5.3%), 12 patients upstaged to stage IIA, 5 to stage IIB, and 6 to stage IV. However, histopathology confirmed distant metastases in only 3 patients (0.7%, 3/435). Overall, upstaging was pathologically confirmed in 11 patients, whereas it was not confirmed in 12 patients, with the discordant cases being predominantly attributable to false-positive nodal findings. PET/CT findings led to treatment modification in only 0.9% (4/435) of the cohort.

In this cohort of asymptomatic patients with clinical stage I-IIA breast cancer, PET/CT rarely identifies additional metastatic disease and frequently results in false-positive findings. These results suggest a selective, risk-adapted use of PET/CT rather than routine staging in early-stage breast cancer, particularly in resource-constrained healthcare settings, and should be interpreted in the context of the study's retrospective design.