Background: Pazopanib was approved for advanced soft tissue sarcoma as a second- or third-line therapy based on the clinical trial “Pazopanib for metastatic soft-tissue sarcoma” (PALETTE). We hypothesized that the real-world experiences may be significantly different from the clinical trial results. Methods: We analyzed the response pattern of patients with advanced soft tissue and bone sarcoma who received pazopanib treatment between 1 January 2011 and 31 October 2018 in Kaiser Permanente Northern California. Results: A total of 123 patients with 23 different histologic subtypes were assessable. One patient with low-grade fibromyxoid sarcoma obtained complete response (CR) after 2 months of treatment with pazopanib, 12 patients (9.7%) obtained partial response (PR), 34 patients (27.6%) had stable disease (SD), while 76 patients (61.8%) developed progressive disease (PD). The disease control rate (DCR) was 46.3% (CR + PR + SD). Among the 12 patients with PR, 3 had undifferentiated pleomorphic sarcoma (UPS), 4 had leiomyosarcoma (LMS), 2 had pleomorphic rhabdomyosarcoma, 1 had pleomorphic liposarcoma, 1 had dedifferentiated liposarcoma, and 1 had angiosarcoma. The median duration of response was 9 months. Two patients with Ewing’s sarcoma had SD for 6 and 13 months, and two patients with osteosarcoma had SD for 6 and 9 months. Among 65 patients assessed at 8 weeks, 9 had a response, and 10 had SD. Among 104 patients assessed at 12 weeks, 12 had a response, and 26 had SD. The median progression-free survival (PFS) was approximately 3 months for all 123 cases and for patients with UPS and LMS. Conclusions: Our cohort of patients with advanced soft tissue and bone sarcoma in Northern California treated with pazopanib had diverse histologic subtypes. The response rate (CR + PR) was higher than that of the PALETTE trial, while the DCR and the median PFS were significantly lower. The observation of PR in two patients with liposarcoma and durable SD in several patients with bone sarcoma indicates that pazopanib has activity in liposarcoma and bone sarcoma.

FIG 1. Hematoxylin and eosin staining of the biopsy specimen from the bladder mass, shown in low (left panel) and high (right panel) magnification. The arrow in the left panel indicates the area highlighted in the right panel.

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e23556 Background: Synovial sarcoma is an aggressive soft tissue sarcoma that predominantly affects young patients with high rate of relapse and mortality. Systemic study of patients’ presenting symptoms and possible delay of seeking medical attention is lacking. Methods: We retrospectively reviewed the electronic records of all patients diagnosed with synovial sarcoma from 2005 to 2016 within Kaiser Permanente Northern California to identify the pattern of presenting symptoms and its correlation with outcomes. Results: Of the 77 patients with synovial sarcoma, 64 had early stage disease and 13 had metastatic disease at diagnosis, with median age at diagnosis of 47 years. Anatomically, 48 patients had primary disease at the extremity, 12 trunk, and 17 visceral. Median duration of follow up is 40 months. The median time from symptom to first medical appointment (TTM) is 3 months (range 0.1 to 180 months). Nine out of 13 patients who presented with metastatic disease were visceral primary. For the 60 patients with an extremity/trunk primary, patients who presented with pain without a palpable mass had a median duration of TTM of 12 months, compared to the TTM of 3 months for patients who presented with a palpable mass. The relapse rate (RR) and disease-free survival (DFS) for patients with an extremity/trunk primary who presented with pain but without a palpable mass were significantly worse when compared to patients who presented with a palpable mass (RR 50% vs. 26.5%, and DFS 27 vs. 42.5 months, p < 0.005). TTM was inversely correlated with DFS for the 64 cases with early stage disease and for the 60 cases with extremity/trunk primary (p < 0.00000001). Of the 11 patients with a foot primary, a similar pattern of TTM and DFS was also observed. Conclusions: Patients with synovial sarcoma who presented with pain but without a palpable mass had longer TTM, worse DFS and higher RR compared to patients who presented with a palpable mass. Longer TTM was associated with worse DFS.