3.P.35 “SPONTANEOUS” REGRESSION OF ADVANCED RETROPERITONEAL LEIOMYOSARCOMA AFTER THE END OF SALVAGE CHEMOTHERAPY

Abstract

A case of advanced retroperitoneal leiomyosarcoma is reported in a patient, who experienced a complete regression of her fatal illness.

A 66-year old woman presented with a 1-year history of intermittent lower abdominal pain. An ultrasonogram (USG) and computed tomography (CT-scan) revealedmultiple soft tissue masses particularly in the lower retroperitoneal space and also 3 liver nodules. USG-guided biopsy was done and histologically confirmed poorly differentiated leiomyosarcoma. The patient underwent successful macroscopically complete en bloc resection of all tumor masses with the exception of 12 liver metastases which had been resected 6 weeks after the initial surgery. 11 months later USG showed disease progression with diffuse inoperable liver metastases, intraperitoneal and retroperitoneal tumor nodules. We introduced salvage chemotherapy (ChT), using intravenous infusion of ifosfamide 1.8 g/m2 on days 1–3 with mesna, and intravenous bolus injection of doxorubicin 60 mg/m2 on day 1. After 4 courses of treatment USG showed partial regression of metastatic disease. When the patient received the 8th, i.e. the last cycle of ChT, USG confirmed further disease regression with only 2 residual metastases in liver. 6 months later USG showed further regression of liver metastases. Another follow-up USG at 9 months and 12 months did not reveal evidence of residual metastases. Almost 2 years after the end of ChT the patient is asymptomatic, well and has no evidence of disease at 41 months after the diagnosis.

The “spontaneous” further regression of metastatic leiomyosarcoma after the end of salvage ChT in our patient would be exceptional phenomena. Although we cannot exclude the remote possibility of “delayed” further response to ChT, generally poor response rate to ChT in leiomyosarcoma would make it very unlikely.