We investigated whether the whole-body maximum standardized uptake value (WBSUVmax) and whole-body metabolic tumor volume (WBMTV) measured by 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can further improve the prognostic stratification of patients with locally advanced breast cancer (LABC).
We prospectively enrolled 109 consecutive women (mean age 52±11 years, range 27–77 years) with pathologically proven LABC who underwent pretreatment FDG PET/CT. WBSUVmax and WBMTV were measured in all malignant lesions. Kaplan – Meier analysis was computed. The Cox proportional hazards model was used with age, histopathological and immunohistochemical features (estrogen/progesterone and HER2 expression, proliferation index and grading), tumor nodal metastasis staging, WBSUVmax and WBMTV to predict overall survival (OS) and progression-free survival (PFS).
The median WBMTV was 14.63 cm3 (range 0.03–708.55 cm3) and the WBSUVmax was 16.88 (range 1.75–86.57). The patients with higher WBMTV (≥ 14.63 cm3) and higher WBSUVmax (≥ 16.88) were more likely to have higher TNM staging (p=0.025 and p=0.105; respectively). The median follow-up for the surviving patients was 26 months, with a range of 15–42 months. The median survival between the patients with low WBSUVmax (< 16.88) and high WBSUVmax (≥ 16.88) was different, although not statistically significant [41 vs 37.3 months for death (p=0.249) and 38.2 vs 32.9 months for progression (p=0.107)]. Conversely WBMTV resulted higher in alive patients than the counterpart (median value: 15.2cm3 vs. 11.4cm3, respectively; p=0.750), but lower in disease-free patients (14.52cm3) than recurrent ones (30.5cm3). The uni- and multivariate analyses showed that only WBSUVmax was an independent prognostic factor for death and progression [hazard ratio = 1.12 (95% confidence interval 1.00–1.26) for death (p=0.038) and 1.04 (95% confidence interval 1.0–1.07) for progression (p=0.029)].
WBSUVmax is an independent predictor for progression and death in patients with LABC. Incorporation of WBSUVmax with clinical data can provide a more detailed prediction of prognosis than tumor staging alone.