Prognostic Impact of (18)FDG-PET-CT Findings in Clinical Stage III and IIB Breast Cancer

BACKGROUND: This study prospectively evaluated the yield of fluorodeoxyglucose positron emission tomography/computed tomography ((18)FDG-PET-CT) in patients with clinical stages II and III breast cancer and the impact of PET-CT results on prognosis. METHODS: In the course of 71 months, 254 consecutive patients with clinical stages II and III breast cancer (based on clinical examination, mammography, breast magnetic resonance imaging, and locoregional ultrasonography) underwent (18)FDG-PET-CT. The yield was assessed in the whole population and for each American Joint Committee on Cancer subgroup. The prognostic impact of PET-CT findings was analyzed. Tests of statistical significance were two-sided. RESULTS: (18)FDG-PET-CT changed the clinical stage in 77 of 254 patients (30.3%; 95% confidence interval [CI] = 25.0% to 36.2%). It showed unsuspected N3 disease (infraclavicular, supraclavicular, or internal mammary nodes) in 40 patients and distant metastases in 53. PET-CT revealed distant metastases in 2.3% (1 of 44) of clinical stage IIA, 10.7% (6 of 56) of stage IIB, 17.5% (11 of 63) of stage IIIA, 36.5% (27 of 74) of stage IIIB, and 47.1% (8 of 17) of stage IIIC patients. Among 189 patients with clinical stage IIB or higher disease and adequate follow-up, disease-specific survival was statistically significantly shorter in the 47 patients scored M1 on (18)FDG-PET-CT in comparison with those scored M0, with a three-year disease-specific survival of 57% vs 88% (P < .001). In multivariable analysis, only distant disease on PET-CT and triple-negative phenotype were statistically significant prognostic factors. The relative risk of death was 26.60 (95% CI = 6.60 to 102.62) for M1 vs M0 patients. CONCLUSIONS: The yield of (18)FDG-PET-CT appeared substantial in patients with clinical stage IIB or higher breast cancer. In these patients, (18)FDG-PET-CT provided powerful prognostic stratification.