Feasibility of FDG PET/CT to monitor the response of axillary lymph node metastases to neoadjuvant chemotherapy in breast cancer patients.
OBJECTIVE
The aim of this study was to assess the accuracy of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT to visualize lymph node metastases before the start of neoadjuvant chemotherapy and to determine how often the visualization is sufficiently prominent to allow monitoring of the axillary response.


METHODS
Thirty-eight patients with invasive breast cancer of >3 cm and/or lymph node metastasis underwent FDG PET/CT before neoadjuvant chemotherapy. The results of the FDG PET/CT were compared with those from ultrasonography with fine-needle aspiration (FNA) cytology or sentinel node biopsy. Patients suitable for response monitoring of the axilla were defined as having either a maximum standardized uptake value (SUV(max)) >or= 2.5 or a tumour to background ratio >or=5 in the most intense lymph node.


RESULTS
The sensitivity and specificity of FDG PET/CT in detecting axillary involvement were 97 and 100%, respectively. No difference existed between the SUV(max) of the primary tumour and that from the related most intense lymph node metastasis. Moreover, the mean tumour to background ratio was 90% higher in the lymph nodes compared to the primary tumour (p = 0.006). Ninety-three per cent of the patients had sufficient uptake in the lymph nodes to qualify for subsequent response monitoring of the axilla. A considerable distinction in metabolic activity was observed between the different subtypes of breast cancer. The mean SUV(max) in lymph node metastases of oestrogen receptor (ER)-positive, triple-negative and human epidermal growth factor receptor 2 (HER2)-positive tumours was 6.6, 11.6 and 6.6, respectively.


CONCLUSIONS
The high accuracy in visualizing lymph node metastases and the sufficiently high SUV(max) and tumour to background ratio at baseline suggest that it is feasible to monitor the axillary response with FDG PET/CT, especially in triple-negative tumours.
Department of Surgical Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
Marieke E
ME
Straver
Tjeerd S
TS
Aukema
Renato A Valdes
RA
Olmos
Emiel J T
EJ
Rutgers
Kenneth G A
KG
Gilhuijs
Margaret E
ME
Schot
Wouter V
WV
Vogel
Marie-Jeanne T F D Vrancken
MJ
Peeters
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18