Correlation of 18FDG PET-CT with SPET-CT lymphoscintigraphy to guide surgical management of the axilla in patients with T2 or T3 breast cancer.

Abstract

623 Background: The aim of this study was to assess the impact of 18 FDG PET-CT (FDG-PET) and sentinel lymph node (SLN) localization by lymphoSPET-CT for the surgical management of the axilla in patients with T2,T3 breast cancer. Methods: 69 patients with T2 or T3 breast cancer (20-40 mm) were enrolled. Both FDG-PET and lymphoSPET-CT were performed for all 69 patients. FDG-PET was performed first to analyze breast and axillary area. Two to 4 days after, SLN SPET-CT was performed. When a focal accumulation of FDG was noted and related to one or more possible axillary metastases, it was compared with SLN as identified by SPECT-CT lymphoscintigraphy. Concordance and discordance of node localization were noted. Results: a focal axillary FDG uptake was found in 30 patients (43.4%). For these 30 patients, preoperative lymphoSPET-CT revealed SLN in 26. All the 26 SLNs were in the same CT location as the focal FDG uptake. SLN biopsy procedure was done in these 26 patients and revealed node metastases in 16 cases (61.5%). Axillary lymph node dissection (ALND) was performed when SLN was metastatic. For the 4 patients with focal axillary FDG uptake but no SLN detected by lymphoSPET-CT, ALND was performed and revealed axillary metastases in all cases. For the 39 patients (56.6%) for whom no focal FDG uptake around axillary region was found, lymphoSPET-CT always identified SLN which was when biopsied and followed by ALND only when metastatic. 3/39 (7.5%) SLN were metastatic, 36/39 (92.5%) SLN were healthy. So correlating 18FDG PET-CT with lymphoSPET-CT seems to be very important in cases of T2 and T3 breast cancer: (1) when a focal FDG uptake is found and no SLN is found by lymphoSPET-CT, ALND is indicated; (2) when a focal FDG uptake is found and is anatomically correlated with SLN as identified by lymphoSPET-CT, SLN biopsy procedure seems to be allowed and safe because node biopsy is related certainly with PET suspect node; and (3) in case of no focal FDG uptake in axillary area, SLN biopsy procedure is probably as safe as for T1 patient. Conclusions: if these preliminary results were to be confirmed, correlating 18FDG PET-CT with SPET-CT lymphoscintigraphy will allow avoiding systematic ALND in patients with T2 or T3 breast cancer. No significant financial relationships to disclose.