Retroperitoneal sarcoma--the continued challenge for surgery and oncology.

Retroperitoneal sarcomas (RS) are rare malignant tumours with an incidence rate of about 1-2 cases per million per year. Therefore only a few centres are able to acquire more experience in this field. Tumours are usually of large size, due to slow growth and uncommon symptoms. Different histologic types, grades and rare incidence make any comparison difficult. Radical excision including adjacent organs, called "en-block" resection, is the treatment of choice, however it is very often difficult to obtain adequate free margins around the tumour. Complete tumour excision remains a challenge even for an experienced surgeon. In the published series, resectability ranges from 38 to 100% with radicality rate between 8 and 95%. Local recurrence is very common (33-86%), with rare distant metastases (max. 33%), so local failure is usually the cause of death. It is well known that histological grading and completeness of surgery determine the chance of survival. Five-year survival rates after radical excision ranged from 62-92% in well-differentiated tumours, compared with 16-48% in nondifferentiated sarcomas. There is no evidence that adjuvant or neoadjuvant treatment affects the prognosis. Only the development of an international registry of retroperitoneal sarcoma and co-operative intergroup studies can help in evaluating treatment and in applying innovative multimodal therapies to these neoplasms.