Evaluation of SPECT-CT scintigraphy for detection of sentinel lymphnodes in early stage breast cancer patients with respect to body mass index

Objectives The present study aimed at evaluating the influence of body mass index (BMI) on sentinel lymph node (SLN) detection with SPECT-CT in early staged breast cancers patients

Methods 111 histopathologically proven female breast cancer (Mean age:48.75y; T1,T2,N0,M0), who underwent clinical examination/ultrasound for N0 axillary lymph node status, were included in this prospective study. All patients underwent SLN mapping (SLNM) by ^99mTc-sulphur colloid method (planar, SPECT-CT imaging and gamma probe). Subareolar injection of radiotracer (median dose:19-74MBq) was given in upper medial quadrant of diseased breast. 91 of these patients also underwent SLNM with blue dye. Apart from BMI, menopausal status, tumor location and T-stage, mammography category, histopathology, immunohistochemistry (IHC) and time elapsed between injection and surgery, were also assessed

Results Planar, SPECT/CT, Gamma probe and blue dye individually detected SLN in 66, 86, 91 and 78% patients, respectively. Significantly decreased number of SLN were visualized on colloid imaging in patients with BMI ≥25 in both categories (p<0.05). SPECT-CT had fair agreement with gamma probe. Blue dye had little advantage (1.09%) over SPECT-CT in SLNM. SLNM with Gamma probe, SPECT-CT and blue dye were not significantly affected by menopausal status, tumor location and T-stage, mammography category, histopathology and IHC (p>0.05). In patients with higher T-stage and invasiveness, planar had a lower SLN detection rate. SLNM with gamma probe decreased with increasing time between injection of radiocolloid and surgery

Conclusions Higher BMI interferes with the detection of sentinel nodes using ^99mTc-sulphur colloid. However, SPECT-CT can successfully overcome the limitations of planar imaging by reducing both the false positive and false negative detection rate