Comparative Study Between Fdg-pet (Fluorine-18 Labelled 2-fluoro-2-deoxy-d-glucose-positron Emission Tomography) and Sentinel Lymph Node Biopsy in Detecting Loco-regional (Axillary) Lymph Node Metastasis in a Carcinoma Breast

Abstract Background : Axillary lymph node dissection (ALND) has been part of the surgical treatment of Carcinoma breast. Recently, increasing number of early detections of breast cancer patients led to a reconsideration of the need for axillary dissection, as many of patients with carcinoma of the breast show no involvement of axillary lymph nodes. The dissection is carried out as a staging procedure, to rule out occult metastases. Sentinel node biopsy (SNB) has been introduced to avoid unnecessary axillary dissection. In contrary as a non-invasive modality is FDG-PET computed tomography scanner, a method which may be able to detect clinically occult metastases pre operatively. AIM & OBJECTIVES: Comparison between SNB and FDG-PET to asses reliability in detecting occult axillary metastasis in clinically node negative Carcinoma breast patient. MATERIAL AND METHOD: 126 diagnosed breast cancer patients with clinically node negative, operated with mastectomy plus SNB were studied. All patients were pre operatively evaluated with 18-FDG-PET. All patients underwent sentinel lymphoscintigraphy. Patient with positive 18-FDG-PET, SNB underwent axillary dissection. Pre operative PET-CT result is compared with histopathology results of SNB and ALND. RESULTS: Out of 126, age group of 33 to 86 year. 45 had metastasis in axillary nodes. Sensitivity of FDG-PET for detection of axillary occult metastases was low (13.33%), although specificity was acceptable (91.36%) while Sensitivity of SLNB for detection of axillary occult metastases was high (73.33%), although specificity was very high (95.06%). Both FDG-PET and Sentinel Lymph Node Biopsy show correlation with histopathology in detecting loco-regional (axillary) lymph node metastasis in breast carcinoma. However, SLNB has much higher sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy compared to FDG-PET, indicating SLNB is a more reliable method for this detection. Conclusion : Conclusion of this study strongly supported by the statistical significance of both tests but favours SLNB as the superior diagnostic tool. As the specificity is high, sentinel lymph node biopsy can be avoided in FDG-PET positive for axillary metastasis breast carcinoma and straight away proceed with axillary lymph node detection. But as sensitivity is low, FDG-PET negative breast carcinoma patients shouldn’t exclude possibility of axillary metastasis and further should do SLNB to detect axillary occult metastases.