Clinical prognostic factors in advanced epithelioid haemangioendothelioma: a retrospective case series analysis within the Italian Rare Cancers Network.

BACKGROUND: This multicentric, retrospective study conducted within the Italian Rare Cancer Network describes clinical features and explores their possible prognostic relevance in patients with advanced epithelioid haemangioendothelioma (EHE) started on surveillance. PATIENTS AND METHODS: We collected data on adult patients with molecularly confirmed, advanced EHE consecutively referred at five sarcoma reference centres between January 2010 and June 2018, with no evidence of progressive disease (PD) and started on surveillance. Overall survival (OS) and progression-free survival (PFS) univariable and multivariable Cox analyses were performed. In the latter, due to the low number of cases and events, penalized likelihood was applied, and variable selection was performed using a random forest model. RESULTS: Sixty-seven patients were included. With a median follow-up of 50.2 months, 51 (76%) patients developed PD and 16 (24%) remained stable. PD at treatment start did not meet RECIST version 1.1 in 15/51 (29%) patients. The 3-year PFS and OS were 25.4% and 71.1%, respectively, in the whole population. Tumour-related pain (TRP) was the most common baseline symptom (32.8%), followed by temperature (20.9%), fatigue (17.9%), and weight loss (16.4%). Baseline TRP (P = 0.0002), development of TRP during follow-up (P = 0.005), baseline temperature (P = 0.002), and development of fatigue during follow-up (P = 0.007) were associated with a significantly worst PFS. An association between baseline TRP (P < 0.0001), development of TRP during follow-up (P = 0.0009), evidence of baseline serosal effusion (P = 0.121), and OS was recorded. CONCLUSION: Because of the poor outcome observed in EHE patients presenting with serosal effusion, TRP, temperature, or serosal effusion, upfront treatment in this subgroup could be considered.