STEREOTACTIC RADIOTHERAPY FOR MANAGEMENT OF PANCREATIC LEIOMYOSARCOMA METASTASIS

Case presentation: A 61-year-old female patient with primary retroperitoneal leiomyosarcoma diagnosed in 2007 who underwent surgical treatment and adjuvant radiotherapy, 45Gy in 25 sessions. Three years later, the patient evolved with pulmonary, pancreatic and vesicular metastases, confirmed by biopsy, and had a good response chemotherapy treatment, which was discontinued in March 2017. In PET-CT performed in 2018, there was persistence in the proximal nodule of the pancreas, with signs of progression. The pacient received stereotatic radiation therapy, dose of 25Gy in 5 fraction, avoiding systemic treatment. After 1 year, total tumor regression was confirmed by PET-CT examination. Discussion: Retroperitoneal leiomyosarcoma is the second most common type of soft tissue tumor. These are tumors that may behave aggressively, and the most frequent sites of distant spread are lungs and liver. Pancreatic metastasis are very rare. In this case, patient had multiple distant metastases, and she underwent chemotherapy and there was an excellent response. However, there was later progression in a single site (pancreas). To avoid systemic treatment, local stereotactic external radiotherapy was chosen after multidisciplinary discussion. There was an excellent response, which avoided systemic treatment. The patient had no side effects. Final comments: Pancreatic metastasis secondary to retroperitoneal leiomyosarcoma is a rare event with high resistance to conventional treatments. The reported case brings to light the discussion of a complex situation. Since treatment with stereotactic radiotherapy was positive, and the response to treatment was confirmed by PET-CT, it is expected that more cases can be resolved using this technique, provided they are well selected.