Monitoring of response of patients with locally advanced breast carcinoma (LABC) to neoadjuvant chemohormonotherapy using 18FDG-positron emission tomography-CT (18FDG-PET-CT)

Abstract

Objective: Patient with advanced breast carcinoma usually required neoadjuvant chemotherapy prior to surgical excision. There is also increase use of hormonotherapy as a neoadjuvant agent. The aim of the study is to validate the value of FDG PET-CT scan in monitoring the pathologic response to therapy in this group of patients. Method: This is an ongoing prospective study. Patients receiving neoadjuvant chemohormonotherapy for breast carcinoma size ≥ 3 cm were recruited. Each patient underwent 2-views mammography, ultrasonography and 18FDG-PET-CT scan before and after 3 cycles of therapy. All patients underwent modifi ed radical mastectomy or breast conservation surgery. The clinical, mammographic, ultrasonographic and positron emission tomographic size, standardized uptake values (SUVmax and SUVavg), lesion glycolysis volume (PET volume x SUVmax) pre- and post- treatment were recorded. Imaging results were compared with the clinical response and pathologic response as determined from the post therapy surgical specimen pathologic size and correlated using bivariate analysis. Results A total of 26 patients were included in the study. The FDG-PETCT scan show improvement in SUVmax in 21/26 patients (80.8%), improvement less than 10% in 4/26 patients (15.4%) and deterioration in 1/26 patients (3.8%). Using lesion glycolysis volume FDG PET-CT show improvement in 18/26 patients (69.2%), improvement less than 10% in 6/26 patients (23.1%) and deterioration in 2/26 patients (7.7%). In correlation with the percentage change in pathological response, the percentage change in SUVmax has a signifi cant correlation coeffi cient of 0.668, while the percentage change in lesion glycolysis volume has a signifi cant correlation coeffi cient of 0.433. The percentage change in size by clinical assessment has a correlation coeffi cient of 0.338. Conclusion: 18FDG-PET is an effective way of objectively monitoring tumor response to therapy. The percentage change in SUVmax and lesion glycolysis volume is positively correlated with pathologic response. Both measurements are better correlated than clinical size assessment alone. 18FDG-PET has substantial potential as an early non-invasive metabolic assessment of the effi cacy of neoadjuvant therapy in LABC. Defi nitive conclusion would be drawn after completion of the trial.