Primary Retroperitoneal Tumors: Symptomatology, Diagnosis, Operative and Postoperative Treatment – Our Five Years Experience

Retroperitoneal tumors today are still a diagnostic and therapeutic surgical challenge due to their rarity, late symptomatic manifestation, complex anatomical topographic localization and the contact with the vital structures. Of these, according to some studies, about 40% have benign and about 60% malignant characteristics, and according to other authors malignant tumors are four times more common than benign. Benign tumors can be of different origin and malignant can be primary or secondary metastatic lesions. The primary retroperitoneal neoplasm’s account for 0.1-0.2% of all malignancies in the human body. 80% of them have mesodermal origin: liposarcoma (30%), leiomyosarcoma, malignant fibrotic histiocytoma and 20% have neural origin. Liposarcomas are rare cancer of the connective tissues that resemble fat cells under microscope. Retroperitoneal sarcomas account for about 18% of all soft tissue sarcomas. Local recurrences at high stages of retroperitoneal sarcomas are the most common cause of death in post-operative patients. The aim of the study was to (1) Determining of the percentage of the primary retroperitoneal tumors in relation with the tumors of the other organs in the retroperitoneum (kidneys, adrenal glands and ureters) in patients’ undergone surgical treatment at the Urology Department at the General City Hospital "8th September"-Skopje, for the last five years. Determining of the ratio between the benign and malignant retroperitoneal tumors in our study group. Analysis of the diagnosis, operative and post-operative treatment and follow-up of the patients with retroperitoneal sarcoma. Comparative analysis of the results obtained with the existing data in the world literature and relevant scientific papers. The study covers 220 patients with retroperitoneal tumors treated at the Urology Department at the General City Hospital "8th September"-Skopje, in the period between 01.03.2015 to 01.03.2020. All cases of sarcoma retroperitoneal tumors and metastatic tumors were treated with meticulous open radical surgical removal of the tumor whereas the benign tumors (lipoma, echinococcus and retroperitoneal cystic teratoma) were treated with laparoscopic procedure. Patients with malignant tumors were treated postoperatively at the Oncology Clinic at the Medical Faculty in Skopje. CT, MR, ultrasound, PET scan and frequent check of the tumor markers were used for the patients follow up for the past three years. None of the patients with primary malignant tumors received neo adjuvant therapy. Mean data, percentage representation and graphical representation of the comparative analyzes were used for statistical data processing. Of the 220 patients treated with a tumor in the retroperitoneum, 19 (8,64%) had primary retroperitoneal tumors. Of those, 11 patients or 5% had primary malignant tumor, 4 patients (1,81%) had metastatic retroperitoneal tumor and 4 patients (1,81%) had benign tumor. The histopathologic finding revealed: liposarcoma in 9 patients (4,09%), one patient with teratocarcinoma (1,81%) and one patient with neurofibrosarcoma (1,81%). The postoperative two years follow up of the patients with retroperitoneal sarcoma (RPS) showed local recurrence and mortal outcome in 2 out of 11 patients (18%). Of the rest 9 patients with RPS, 7 patients received chemotherapy and 2 patients did not receive any chemotherapy due to the continual negative results of the CT, MRI, PET scan and tumor markers. Overall 3 years survival is 81,8%. Compared with other studies where RPS are present in one third of the primary retroperitoneal tumors, our study showed retroperitoneal sarcoma presence in 57,89%. The etiology of such high percentage is a subject for further studies. Local recurrence appeared in 2 patients with primary malignant retroperitoneal tumor and in all 4 patients with secondary metastatic tumors of the retroperitoneum, regardless the radical surgical and oncology treatment due to the presence of the high malignant stage. All of the patients with retroperitoneal tumors had general symptoms (back pain, weakness and weight loss) and gained first diagnose by ultrasound examination. Our study showed a high percentage of primary retroperitoneal tumors with 8,64% compared to the total number of operated retroperitoneal tumors. Of those 5% were primary malignant retroperitoneal tumors (liposarcoma, neurofibrosarcoma and teratocarcinoma). 60% of the treated primary and secondary malignant retroperitoneal tumors belonged to liposarcoma which is much higher percentage of the representation described in the literature to date. The high percentage of 3 years survival (81,8%) confirmed our decision for radical surgical treatment as soon as possible, without prior neoadjuvant oncology therapy. Postoperative chemotherapy is necessary for longer survival especially in patients with stage T2G2N0M0 and above. The fact that the 2 patients with RPS did not receive any oncology therapy, and are still in good health without any local recurrence, confirms that precision surgery and diagnosing the tumor at its early stage are key to successful treatment of the retroperitoneal malignant tumors. Laparoscopic surgery in our study proved to be an appropriate method in the treatment of benign tumors while open surgery is still the method of choice for radical removal of sarcomas according to our experience.