The Usefulness of SPECT/CT in Sentinel Node Mapping of Early Stage Breast Cancer Patients Showing Negative or Equivocal Findings on Planar Scintigraphy

• Main Authors: Maimoona Siddique, Muhammad Nawaz, Humayun Bashir
• Format: Article
• Language: English
• Published: Mashhad University of Medical Sciences 2018-06-01
• Series: Asia Oceania Journal of Nuclear Medicine and Biology
• Subjects: Sentinel node; SPECT/CT; Planar Scintigraphy; Breast cancer
• Online Access: http://aojnmb.mums.ac.ir/article_10720_0b9c7827cebfdb7a504243b3fa7a5565.pdf

Objective(s): This study sought to determine the diagnostic yield of SPECT/CTin localizing axillary sentinel lymph nodes (SLNs) in early breast cancer patientswhere planar scintigraphy (PS) was equivocal or negative.Methods: Prospective analysis of early stage breast cancer patients with nonpalpableaxillary nodes undergoing SLN localization prior to nodal sampling foraxillary staging. PS findings were categorized as: Category A: non-visualizationof SLN; Category B: unusual uptake location; Category C: equivocal uptake /difficult interpretation. The K-coefficient of Cohen was used to evaluate thecorrelation between PS and SPECT/CT results. PS and SPECT/CT images wereinterpreted separately, and SLN identification on each of the modalities wascorrelated to BMI (Body mass index) and peroperative radio guided results.Results: Between April 2015 and January 2017, 1028 early breast cancer casesunderwent sentinel lymphoscintigraphy. Of total, 134 (13%) patients underwentSPECT/CT in addition to PS. All were females with mean age of 48.15 years (range:26-82 years). Right sided in 68, left in 64 and 2 with bilateral carcinoma. By TNMclassification: 49 (37%) T1, 78 (58%) T2 and 7 (5%) had DCIS/Paget’s disease.Overall SLNs were detected on both PS and SPECT/CT in 60% cases. Of categoryA (n=54); 35/54 (64%) SLN localized on SPECT/CT; 32 were level-I; 2 Level-II;1 Level-III nodes. In 19, SLN was not localized. Of category B (n=18), 5 hadprior lumpectomy, SPECT/CT localized tracer uptake to 17 level-I sentinelnodes, 3 level-II and level III / IMC in 9.Of category C (n=62), 29 had prior lumpectomy. SPECT/CT confirmed SLN in allthe cases. Radio-guided surgery confirmed SPECT/CT results. The correlationbetween the two techniques was low (K=0.34). Where PS was negative; SPECT/CT localized nodes in statistically significant number of cases (P=0.01). PSidentified SLN uptakes in 80/134 (60%) cases with a mean BMI of 21.6±4.8 kg/m2 while SPECT/CT detected ‘‘hot’’ nodes in 115/134 (86%) cases with a meanBMI of 29.6±5.6 kg/m2. For overweight/obese patients (n=59) (BMI>25 kg/m2),PS failed to identify SLNs in 49 and SPECT/CT failed to do so in 18 (P