Systemic therapy in advanced dermatofibrosarcoma protuberans: Imatinib and beyond.

Abstract

e22523 Background: Imatinib is the standard treatment of advanced Dermatofibrosarcoma (DFSP). However ideal treatment of advanced DFSP patients, who have progressive disease (PD) on imatinib, remains an unanswered question. Methods: We retrospectively analysed consecutive advanced DFSP patients who presented to AIIMS Sarcoma Medical Oncology clinic between January 2016 and January 2019. Results: There were eleven patients, with median age of 35 years, seven (63.6%) of which were males. Fibrosarcomatous transformation was present in six (54.5%) patients. Four (36.4%) had locally advanced disease, while seven (63.6%) had metastatic disease. Primary site was trunk in eight (63.7%) patients. Three (75%) of the four patients who received neoadjuvant imatinib, underwent complete surgical resection. Initial dose of imatinib was 400mg OD in eight (72.7%) patients, 600 mg OD in two (18.2%) and 800 mg OD in one (9.1%) patient. The best response to imatinib was Partial response (PR) in nine (81.8%) patients, stable disease (SD) in one (9.1%) and primary PD in one (9.1%) patient. Median progression free survival (PFS) was 16 months, after a median follow up of 14 months. Five (45.4%) patients had PD on imatinib. As mentioned in table, strategies used in these patients were pazopanib (n = 3), doxorubicin (n = 2), other chemotherapy (n = 2), dose escalation of imatinib (n = 2) and reintroduction of imatinib (n = 1). One patient had prolonged stable disease on pazopanib, while remaining had PD. Conclusions: Imatinib remains prominent first line therapy in advancved DFSP. Though pazopanib has shown some promise, the treatment outcomes in second line therapy and beyond have largely been dismal and need to be studied prospectively.[Table: see text]