Рентгенология & Радиология, 2013, LII 6-11

Comparison of SPECT/CT and planar scintigraphy in the preoperative localization of sentinel lymph nodes in breast cancer

  1. Garcheva, I. Kostadinova, T. Sedloev, J. Palashev

Radionuclide lymphatic mapping is accepted technique in the management of patients with breast cancer especially in initial stages. It is important for the exact anatomic location of the SLN (sentinel lymph node) preoperatively, aiming to reduce the morbidity of lymphatic dissection. The aim of the study is to compare the planar and SPECT/CT techniques with regard to the success of SLNs visualization, to the exactness of their localization and to the rate of detection of unusual lymphatic drainage. Thirty three patients with breast cancer
and clinically negative auxiliary lymph nodes are examined by both: planar and SPECT/CT (Siemens Symbia 2T) scintigraphy for SLN mapping. The subcutaneous, or peritumoral application of 55-74 MBq nanocolloid in 1-4 injection places is done according to the localization and size of the tumor. The criteria do not exclude patients with expected changes in the drainage: previous operation, radiotherapy, or local chemotherapy. The surgery is done on the next day by using blue dye technique or gamma-probe (Europrobe 3) and the histology of the harvested (only auxiliary) lymph nodes was determined. The
planar and SPECT/CT images are separately interpreted. The planar examination depicts SLN in 29 patients (88%) with the following localizations: only ipsilateral auxiliary in 24 patients (73%), and combined auxiliary and extraaxillary in 5 patients (15%). The SPECT/CT examination detects SLN in 30 patients (91%) and the following localizations are identified: ipsilateral auxiliary in 22 patients (67%), and combined drainage in 8 (24%). None of the patients has only extraaxillary drainage. In 2 patients reconsidering of the stage and therapy are done according to the additional findings – enlargelymph node without nanocolloid uptake and in one pulmonary lesions on CT-component. The histology determines positive axilla in 10 patients (30%): 4 micro metastatic SLNs, 3 with involvement of only one – the SLN, and 3 with more than one positive lymph nodes. In the cases with failure of visualization the histology is positive in 3 of 4 cases. In one patient with positive SLN and proved combined lymphatic drainage a supplementation of the radiotherapy is anticipated. Both techniques are sensitive in SLN identification (89- 91%). SPECT/CT is more successful in identification of second, unusual lymphatic drainage. It is also more precise for the correct localization of SLNs. The additional findings from CT are also important for staging of the disease. The decision making process was influenced in 12% of patients according to the obtained data.