Efficacy of the faxitron biovision x-ray machine in intra - operative determination of metastatic foci in a sentinel lymph node

Abstract

Background: Sentinel lymph node biopsy has revolutionized breast cancer management. Its major benefit of reduced axillary morbidity whilst offering outcomes equivalent to axillary lymph node dissection has been shown in various trials. Multiple trials indirectly highlighted the absence of an intra-operative method or test to identify positive lymph nodes. This study aimed to determine if there was an association between the faxitron biovision x-ray machine (FBXM) results and histology for assessing axillary lymph node (ALND) metastasis intra- operatively. Methods: To measure the X-ray attenuation of sentinel lymph node biopsy (SLNB) images on FBXM, the intensity of the image generated was measured to give a value, known as the intensity unit and equivalent to the density of the SLN. This value was then used to determine the likelihood of axillary sentinel lymph node metastasis. The mean intensity and maximum intensity units was recorded and the samples retrieved and sent for routine histology. The agreement between the FBXM and standard histopathology was compared using a Chi- squared test and the independent sample T-test was used to assess whether the minimum and maximum intensity differed significantly. The SPSS Statistical software version 20 was used for data analysis. Results: A hundred and one patient samples were analysed.The FBXM had a sensitivity of 70.8% and specificity of 83.1%. The FBXM had a Positive predictive value of 56.7% and Negative predictive value of 90.1%. FBXM results differed significantly with the gold standard when the Youden index was calculated with the AUC was < 0.6. The p-value was also greater than 0.05 (p-value = 0.148). This meant that there was no significant relationship between the FBXM and the Gold Standard (Histology). Conclusion: The findings suggest that histopathology remains the standard of care in evaluating SLNs.