Retrospective comparison between pre-operative LYMPH node positivity in PET/CT, CT and MR screenings and post-operative LYMPH node metastasis detected in pathology results in epithelial ovarian cancers

Objective: Epithelial ovarian cancer is the most common type of ovarian cancer and is the 5th most common cause of cancer-related deaths in women in western countries. The reason for the high mortality rate of the disease is due to the fact that approximately 70% of patients are diagnosed at an advanced stage. The amount of residual tumor after primary surgery is one of the most important prognostic factors in ovarian cancer. Lymphatic spread is also an important prognostic factor in the early and advanced stage of ovarian cancer. While systematic pelvic and paraaortic lymphadenectomy (SAPL) is a part of optimal debulking in advanced ovarian cancer, in the early ovarian cancer, it gains importance primarily for allowing the phasing of the cancer and it gives a chance to select the possible candidates of adjuvant chemotherapy. Although some retrospective analysis declare completely resection of the tumor in advanced ovarian cancer with systematic pelvic and paraaortic lymphadenectomy (SAPL) having benefits for survival, the well-advanced and unbiased study "Lymphadenectomy in Ovarian Neoplasms (LION)" approves that systemic pelvic and paraaortic lymphadenectomy (SAPL) does not contribute to overall survival (OS) and progression-free survival (PFS) in advanced ovarian cancer (FIGO stage 2B-4), on the contrary, it is even associated with serious postoperative complications. Some authors have raised a contradiction that is whether or not to perform systematic pelvic and para-aortic lymphadenectomy even in advanced ovarian cancer. In this case, determining patients with lymph node metastasis and performing direct lymphadenectomy is very important to avoid potential complications that systematic pelvic and paraaortic lymphadenectomy (SAPL) will bring. This is why this study retrospectively investigates the performance of screening modalities (MR, CT, PET/CT) to detect lymph node metastase lymphadenectomy by demonstrating the power of imaging methods in detecting lymph node metastasis and to protect patients from the complications of systemic pelvic and paraaortic lymphadenectomy (SAPL). Material and Method: The study includes patients with epithelial ovarian cancer who are registered in hospital's electronic file system that is evaluated and followed by Akdeniz University Medical Faculty Gynecological Oncology Surgery Department or Medical Oncology Department, who had dissection of pelvic and/or para-aortic lymph node and had at least one imaging method (MR, CT, PET/CT). According to the data, 89 patients were included in the study. Lymph node metastasis in histopathological reports of these patients was taken as the gold standard. The presence of lymph nodes in imaging modalities (MR, CT, PET / CT) was considered positive and compared with the gold standard pathological lymph node metastasis. Thus, the accuracy, specificity, sensitivity, PPV and NPV of screening methods in predicting lymph node metastasis were calculated. Results: The majority of patients (n= 38, 42.7%) are FIGO stage 3C. As a result of the collected data, 85 of 89 patients included in the study, underwent systemic pelvic and para-aortic lymphadenectomy, while only 4 patients underwent pelvic lymphadenectomy. 73 of the patients had CT, 20 of them had PET / CT and 12 of them had MR. Based on all nodal involvement of CT, its sensitivity, specificity, PPV, NPV and accuracy are 62%, 52%, 57%, 57% and 57% respectively. On the other hand, PET's sensitivity, specificity, PPV, NPV and accuracy are 63%, 66%, 70%, 60% and 65% respectively. When only para-aortic nodal involvement is taken into account, PET's sensitivity, specificity, PPV, NPV and accuracy are 50%, 91%, 80%, 73%, and 75% respectively. Conclusion: According to the data we obtained, it is very difficult to decide whether or not to perform systemic pelvic and para-aortic lymphadenectomy with imaging modalities (MR, CT, PET / CT) and more data are needed. Key Words: PET / CT, MR, CT, Lymphadenectomy, Ovarian Cancer, Pre-operative Screening.