Pre-operative irradiation for retroperitoneal liposarcoma: results of a pilot study

The aim of this study was to evaluate toxicity and benefit of an original method of preoperative irradiation combined with adequate surgery in the treatment of retroperitoneal liposarcoma. Instead of irradiating the whole tumor volume, 50Gy in 25 fractions was delivered to the posterior part of the tumor and the contact zone with the postero-lateral abdominal wall only.

Between mid-2000 and end of 2011, 29 patients were included in this study, 22 with a primary tumor, 7 with a first local recurrence. The results obtained were compared with a well-matched control group operated on by the same surgeon during the same period.

This therapy was well tolerated by all included patients and no difference in toxicity was found between pilot and control group. With a median follow-up of 84 months the oncological results were similar in both groups with a 5 y disease specific survival of 79 and 81% (p: 0.61). However a very significant difference was found according to histotype: five year disease specific survival was 84% (CI 66-93) for the well- differentiated and only 35% (CI 20-51) for the dedifferentiated liposarcoma (p < 0.0001).

This form of combined treatment is well tolerated but superiority could not be demonstrated. Our experience clarifies some of the difficulties facing a randomized clinical trial on this topic.