Prognostic Impact of 18FDG-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.