Baseline Tumor 18F-FDG Uptake and Modifications After 2 Cycles of Neoadjuvant Chemotherapy Are Prognostic of Outcome in ER+/HER2- Breast Cancer.

UNLABELLED: This study investigated whether (18)F-FDG PET/CT performed at baseline and during neoadjuvant chemotherapy (NAC) was able to early depict estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer patients with poor clinical outcome.

METHODS: The NAC regimen consisted of 4 cycles of epirubicin plus cyclophosphamide, followed by 4 courses of docetaxel. The patients underwent (18)F-FDG PET/CT at baseline and after 2 cycles of chemotherapy. After completion of NAC, all patients had breast surgery with axillary lymph node dissection. We assessed the impact of 2 PET parameters, maximum standardized uptake values (SUVmax) and total lesion glycolysis, on event-free survival (EFS).

RESULTS: Ninety-eight consecutive patients with clinical stage II or III ER+/HER2- breast cancer were included. (18)F-FDG PET/CT revealed distant metastases in 14 patients (14%). Overall survival was significantly shorter in these patients than in the 84 patients classified as M0 at baseline (18)F-FDG PET/CT (P < 0.001). In M0 patients, a high SUVmax at baseline was associated with shorter EFS (P < 0.001). Twelve patients had a tumor SUVmax of 10 or greater and a 3-y EFS of 49% (vs. 92% in patients with baseline SUVmax < 10). A low change in SUVmax between (18)F-FDG PET/CT examination before starting NAC and after the second cycle of chemotherapy was also associated with recurrence (P = 0.033), as was a low change in total lesion glycolysis (P < 0.001). Contrarily to PET-based prediction, the extent of pathologic response after completion of NAC (partial/complete vs. nonresponders) was poorly correlated to the risk of relapse.

CONCLUSION: Baseline tumor (18)F-FDG uptake and modifications after 2 cycles of NAC are prognostic of outcome in patients with ER+/HER2- breast cancer.