The value of sentinel lymph node biopsy, magnetic resonance, and PET/CT imaging in showing lymph involvement in endometrial cancer

Objective: We aimed to evaluate the value of sentinel lymph node biopsy (SLNB), magnetic resonance (MR), and PET / CT imaging in showing lymph node metastasis in patients diagnosed with endometrial cancer (EC). Method: A single-center, prospective study was conducted. Patients with histopathologically diagnosed endometrial cancer were included in the study. The spread of the tumor was evaluated by performing MR imaging in all patients and PET / CT imaging in half of the patients before the operation. During the operation, indocyanine green (ICG) injection was applied to the surface and 1 cm deep in the cervical 3 and 9 o'clock direction to all patients, and SLNB was performed by imaging with a fluorescent camera after approximately 20 minutes of waiting. Bilateral pelvic LND was performed in patients with unilateral SLN. Hysterectomy, bilateral salpingooferectomy, and abdominal washing were performed in all patients. Pelvic lymphadenectomy was performed in 77% of the patients and paraaortic lymphadenectomy in 16% of the cases. Sentine lymph nodes were stained with pancytokeratin after hematoxylin and eosin staining in pathology and immunohistochemical evaluation was performed. Results: Thirty patients were included in the study conducted between July 2019 and October 2020. Following the cervical injection of ICG, SLNB was performed by fluorescent imaging in all patients. At least unilateral SLN detection rate was 100%, bilateral detection rate 77%, unilateral detection rate 23%. Lymph node metstasis was observed in 10% of patients. The sensitivity of SLN in demonstrating lymph node metastasis was 67%, its specificity was 100%, its positive predictive value was 100%, and its negative predictive value was 96.4%. All patients with lymph node metastases had tumor size greater than 2 cm and LVSI. Sensitivity of MR imaging in showing lymph node metastasis was 33.3%, specificity was 96.4%, PPD was 50%, NPD was 93%. The sensitivity and specificity of PET / CT imaging to show lymph node involvement was 100%, and the positive and negative predictive value was 100%. No positivity was seen in paraaortic lymph nodes. Conclusion: SLN biopsy has an important role in showing lymph node metastasis and it has the feature of showing a high rate of especially isolated tumor cells and micrometastases. The sensitivity of PET / CT in demonstrating lymph node involvement was found to be high, further studies are needed due to the limited number of patients. Keywords: Lymph node metastasis in endometrial cancer, Indocyanine green (ICG), sentinel lymph node biopsy (SLNB), MR, and PET / CT imaging.