Could semiquantitative FDG analysis add information to the prognosis in patients with stage II/III breast cancer undergoing neoadjuvant treatment?

We investigated whether maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), total lesion glycolysis (TLG) and whole-body (WB) SUVmax, WB MTV and WB TLG measured by ¹⁸F-FDG PET/CT could improve prognostic stratification in patients with stage II/III breast cancer (BC).

We prospectively enrolled 99 consecutive women (median age 50 years, range 27 – 77 years) with pathologically proven stage II/III BC who underwent pretreatment FDG PET/CT. WB SUVmax, WB MTV and WB TLG were measured in all malignant lesions. Survival was analysed using the Kaplan-Meier method. Cox proportional hazards models were constructed to test for relationships among WB SUVmax, WB MTV, WB TLG, and overall survival (OS) and disease-free survival (DFS), after adjustment for age, and histopathological and immunohistochemical features (oestrogen/progesterone and HER2 expression, proliferation index and grade).

The median values of WB SUVmax, WB MTV and WB TLG were 16.2 (range 1.5 – 33.1), 14 cm³ (range 0.03 – 708.6 cm³) and 62.5 (0.06 – 3869.4), respectively. All WB semiquantitative values were higher in patients with higher TNM stage, although not significantly (all p > 0.05). The median follow-up for surviving patients was 30 months, with a range of 13 – 45 months. Both PFS and OS of patients with low WB SUVmax, WB MTV and WB TLG were longer than that of patients with high WB values for progression, although not statistically significant. However, stratifying the patients in accordance with the stage of disease, both PFS and OS were significantly lower in patients with high WB TLG and stage III than in patients with stage II (p < 0.05). In multivariate analyses, WB MTV and WB TLG were independent prognostic factors for PFS (hazard ratio 1.004, 95 % confidence interval 1.002 – 1.006, p < 0.001, and hazard ratio 1.001, 95 % confidence interval 1.000 – 1.001, p = 0.011, respectively).

The addition of WB TLG to clinical data may provide a more detailed prediction of outcome in patients with stage III BC. Moreover, WB MTV and WB TLG are independent factors predicting recurrence of BC. On the contrary, WB SUVmax has poor prognostic significance in this cohort of patients.