Primary neoplasms of the posterior peritoneum mainly originate from the mesoderm (75%), neuroectoderm (24%) or fetal remnants. These tumors develop in the retroperitoneal space from the same tissues of the space and do not concern tumors originating from retroperitoneal organs, such as kidney, pancreas, prostate, etc. tumors. They develop in the retroperitoneal space from the diaphragm to the small pelvis and inguinal regions.

Benign tumors such as lipomas, cysts, have percentages of 10% – 25%, the remaining percentage concerns malignant retroperitoneal tumors with frequency: liposarcomas (33%), leiomyosarcomas (19%), histiocytomas (12%), neurosarcomas (11%), fibrosarcomas (6%), rhabdomyosarcomas (2%) and other rare forms (13%). The histological type of the tumor is not decisive in terms of the behavior of the tumor and the prognosis, but also the therapeutic approach. Of particular importance is the aggressiveness of the tumor (number of cell mitoses) and the degree of malignancy (grading) with the designations êž® for well-differentiated sarcomas, ꞮꞮ for moderately differentiated, ꞮꞮꞮ for poorly differentiated and Vêž® for undifferentiated. These data are obtained from the histological examination.

Retroperitoneal sarcomas are rare tumors, they make up about 15% of soft tissue sarcomas in the body, they appear at any age, but usually between 40-60 years and affect men and women equally. Approximately 11% of patients with primary retroperitoneal sarcoma present with metastases that mainly involve the lung and liver. Surgical excision on healthy tumor margins is the only treatment that offers satisfactory results. The surgical operations of these tumors are considered to be of increased difficulty due to their location and close relationship with other organs of the retroperitoneal space, where it often becomes impossible to resect them within healthy limits. At this point the experience of the surgeon is important. However, even in the case of complete resection, local recurrence rates in the decade vary between 60% and 90%, which is treated surgically. The first surgical intervention is of decisive importance for the outcome of the disease. Additional treatments include radiation and chemotherapy with a poor response.

Patients develop symptoms when the tumor is now large enough. The most common complaint is abdominal or loin pain, a palpable mass in 70% of cases. Also, symptoms arise from the pressure of adjacent organs with obstructive manifestations from the urinary, gastrointestinal and vascular systems (pressure of the inferior vena cava or iliac veins is manifested by swelling of the lower extremities), bleeding from the digestive system due to its infiltration by the tumor .

Diagnosis of the disease includes upper-lower abdominal-pelvic CT scan and abdominal magnetic resonance imaging. Also, angiography may be useful in large tumors to find outgrowth of feeding vessels in anticipation of surgery or preoperative embolization. In case the tumor infiltrates the kidney and may be removed, a pyelogram is performed. Testicular ultrasound is necessary to exclude a testicular tumor with retroperitoneal lymph node metastases. To rule out lung metastases, a chest CT scan is necessary.

The staging of sarcomas of the retroperitoneal space is done with the GTNM grading system (G=grade, T=tumor, N=lymph nodes, M=metastases) and includes four severity stages Ɪ, ꞮꞮ, ꞮꞮꞮ and VꞮ.

The treatment of choice is surgical excision of the tumor on healthy margins. Complete resection in large patient series ranges from 50% to 80%. In 70% at least one organ is infiltrated by the tumor and in 35% the vessels, so resection of the infiltrated organs is necessary. During the surgery, separate neoplastic nodules, satellite tumors, may appear, which are located in the round cytofatty tissue, but also outside the main tumor that must be excluded, otherwise they are a point of recurrence in a short time. Surgery for recurrence has poorer outcomes in patient survival.

Radiotherapy is a complementary treatment for the local control of the disease, but without encouraging results.

Chemotherapy is controversial and used in few cases.

The frequency of recurrence, the disease-free interval and finally the survival of the patients mainly depend on the radicality of the first operation and is completely linked to the experience of the surgeon. The average exclusion rate from different centers is about 50%.

With complete resection of the tumor the five-year survival is between 32% and 100%. Overall survival including partial tumor resection at five years is 11% to 50% and at ten years 10% to 20%.

Patients with a high grade have a high probability of disease recurrence and should undergo frequent imaging. Imaging includes a chest-abdominal-pelvic CT scan every 3 to 6 months for the first two years and annually thereafter. For less aggressive tumors, the same imaging test annually is sufficient.

In the 3rd surgical clinic of Mitera Hospital, of which I have the honor to head as Director, such operations are successfully performed.