[Primary retroperitoneal tumors. Treatment modality and prognostic factors].

Background: Primary Retroperitoneal Tumors (PRT) form a heterogeneous group of malignant mesenchymal and neuroectodermal neoplasms making up only 1% of all solid neoplasms.

Methods: From 1965 to 1997, 27 patients (16 females and 9 males, age range 19-79 years) underwent operations at the General and Cardiovascular Institute of University of Milan for primary retroperitoneal tumors (22 malignant and 5 benign, sarcomas represented 68% of all malignant tumors). A retrospective analysis of these patients was performed to determine the prognostic parameters associated with a favourable prognosis. All patients were admitted with severe abdominal pain or a palpable mass, other symptoms included fewer and weight loss. The median duration of symptoms before presentation was 16 months (range 15 days-5 years). Before surgical treatment abdominal and pulmonary CT scanning and MRN were undertaken on all patients with PRT to define the size of the tumor and the involvement of other retroperitoneal structures.

Results: Complete resection was possible in 54% of malignant tumors (n = 12), incomplete resection was performed in 14% (n = 3) and in 31% (n = 7) only biopsy was possible. Recurrent tumor developed in 25% of patients with total resection (n = 3), (median time to recurrence 5 years). Independent treatment variables (size, signs and symptoms, histopathologic findings and grade) and treatment-dependent variables (type of surgical treatment and adjuvant chemotherapy) were analyzed. Patients with complete resection had a 12 month survival of 100% (n = 12) compared to 50% (n = 1) for those undergoing partial resection and 14.2% (n = 1) for those with simple biopsy. A 24-month survival of the patients undergoing complete resection was 25% (n = 3). Median survival for type of surgical treatment was 28 months for complete resection compared to 14 months for partial resection and only 8 months for biopsy. Twelve-months survival for tumor grade was 100% (n = 7) for low grade tumor (G1), compared to 66.6% (n = 4) for median differentiated tumors (G2), and 37.5% (n = 3) for high grade tumors (G3). Twenty-four-months survival was 28.5% (n = 2) for low grade tumors compared to 16.6% (n = 1) of median differentiated tumors. High grade tumors were associated with a 35-month median survival time compared to 17 months for median differentiated tumors and 10 months for low grade tumors. Other variables (histopathologic findings, size, symptoms) had not significant impact on survival. Operative mortality rate was 3.7% (n = 1). The overall 2 years survival rate in patients with totally resected tumors was 25% (n = 3), (2G1, 1G2), while the 5 year survival rate was 16.6% (n = 2), (2G1).

Conclusions: Complete surgical excision and low grade of the tumor are the most important parameters of survival. Recurrent disease is a vexing problem; a careful and prolonged follow-up based on the use of CT and MRN is recommended.