Background: This study aimed to evaluate the usefulness of serial [(18)F] 2-fluoro-2-deoxy-D: -glucose-positron emission tomography ([(18)F] FDG-PET) in potentially operable breast cancer with neoadjuvant chemotherapy.
Methods: Serial positron emission tomography was undertaken in 66 breast cancer patients who comprised a subset of the population in a phase III randomized neoadjuvant trial at National Cancer Center, Korea. We assessed the peak standardized uptake value (SUVp) in the primary tumor and axillary nodes before and after neoadjuvant chemotherapy and calculated the reduction rate (RR) of the SUVp. By means of a receiver operating characteristic curve, we identified an optimal cutoff value for the RR for predicting the pathologic response and evaluated the prognostic power of this cutoff value.
Results: Ten patients (15.2%) experienced a pathologic complete response (pCR) in the primary tumor, and 19 patients (28.8%) experienced a pCR in the axillary nodes. The mean RR of the SUVp in primary tumors was 70.3% +/- 28.7%, and this value was significantly different by the pathological response (89.2% +/- 11.1% in pCR vs. 66.9% +/- 29.6% in non-pCR, P < .001). When 84.8% of the RR was used as a cutoff value for the pCR, sensitivity and specificity was 70.0% and 69.6%, respectively. Ten patients (15.2%) developed recurrent disease at a median follow-up period of 61.5 (range, 13.5-71.8) months. In a univariate analysis, the 5-year disease-free survival (DFS) was correlated with the clinical T stage (91.1% in T1/2 vs. 71.4% in T3/4, P = .02), HER-2 status (77.8% in positive vs. 96.9% in negative, P = .03), and the 84.8% RR of the SUVp in the primary tumor (95.8% vs. 78.5%, P = .04). HER-2 positivity was a significant independent prognosticator in the multivariate analysis (hazard ratio 8.73, 95% confidence interval 1.03-73.84, P = .04). The presence of a pCR in the primary tumor or nodes was not a prognostic factor in this subset of patients. The RR of the SUVp in the axillary nodes was not correlated with the nodal pCR and DFS.
Conclusions: The RR of the SUVp in the primary tumor was correlated with the pathologic response and DFS. This study suggests the possible prognostic value of the RR in positron emission tomography by neoadjuvant chemotherapy.