Percentage change of primary tumor on (18)F-FDG PET/CT as a prognostic factor for invasive ductal breast cancer with axillary lymph node metastasis: Comparison with MRI

We evaluated the prognostic value of quantitative parameters using dual time point (DTP) (18)F-FDG PET/CT (PET/CT) in invasive ductal breast cancer (IDC) with metastatic axillary lymph nodes (ALN) as compared with dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI. Seventy patients with IDC and metastatic ALN were retrospectively registered. Static PET parameters including maximum standardized uptake value (SUV(max)), metabolic tumor volume (MTV), total lesion glycolysis (TLG) of primary tumor, SUV(max) of ALN (SUV(ALN)), and percentage changes (Δ%) in those parameters were measured with DTP PET/CT. From DCE MRI, peak enhancement value, total tumor angio volume, and proportions of kinetic curve types on delayed-phases were investigated. The average apparent diffusion coefficient (ADC(avg)) was estimated on DWI. To demonstrate the prognostic value of quantitative imaging parameters for recurrence-free survival (RFS), univariate and multivariate analyses were performed using those parameters and clinicohistologic variables. All static PET parameters, %ΔSUV(max), %ΔMTV, and %ΔSUV(ALN) on DTP PET/CT and ADC(avg) on DWI were significantly predictive for disease recurrence. Of clinicohistologic variables, pathologic tumor (pT) diameter, pathologic ALN stage, tumor grade, and hormonal status also were significantly prognostic. After multivariate analysis, %ΔSUV(max) > 25.05 (P = .043), ADC(avg) ≤ 1016.55 (P = .020), pT diameter > 3 cm (P = .001), and ER negative status (P = .002) were independent prognostic factors for poor outcome. Only %ΔSUV(max) of the primary tumor on PET/CT together with ADC(avg), pT diameter, and ER status was an independent prognostic factor for predicting relapse in IDC with metastatic ALN. Percentage change of primary tumor on preoperative PET/CT may be a valuable imaging marker for selecting IDC patients that require adjunct treatment to prevent relapse.