(P 177) ANGIOSARCOMA: AN INCREASING PROBLEM IN THE UNITED STATES

Objective: Angiosarcoma is an aggressive cancer of endothelial cells that can arise in any part of the body, but most commonly occurs in the skin. Angiosarcoma can form without a clear inciting factor or arise as a secondary malignancy after radiation or from chronic lymphedema. Although rare, our prior work suggested that the incidence of angiosarcoma may be rising in the United States (US). We sought to describe the incidence, presenting characteristics, and change over time of angiosarcoma in the US.

Methods: A retrospective cross-sectional database analysis was conducted utilizing the US Cancer Statistics NPCR-SEER Combined Database (USCS), which captures >99% of newly diagnosed US cancers. All US, newly diagnosed angiosarcoma patients between the years of 2001-2017 (n=15,410) were included. Main outcomes were incidence, patient demographics including history of prior cancer before angiosarcoma diagnosis, and extent of disease at presentation. Changes in rates were determined with age-adjustment to the 2000 US Standard Population; percent changes were calculated using the weighted least-squares method.

Results: The US incidence of angiosarcoma nearly doubled between 2001 (653 cases) and 2017 (1166 cases). This corresponded to a rise in population adjusted incidence rate of 1.8% per year (p < 0.01), to a current rate of 3.1 cases per million person-years (95% CI 2.9-3.3) and rise in population at risk (Figure 1). Secondary breast and chest wall angiosarcomas in women represented the largest contribution to increasing incidence (Figure 2). Women were more likely to have secondary cutaneous angiosarcoma of the thorax and upper extremity (80.5% of chest wall/thorax cases in women were secondary vs 24.2% in men and 63.9% of upper extremity cases in women were secondary vs 25.7% in men, p < 0.05), compared to men who were more likely to have secondary angiosarcoma of the head or neck (28.3% vs 19.6%, p< 0.05, Figure 3). Overall, 72.6% were cutaneous/subq/breast (n=11,187), 22.9% were visceral (n=3,523), and 4.5% were unknown or rare primary sites (n=700). Median age at diagnosis was ~65 years for primary cutaneous angiosarcoma and visceral angiosarcomas, and ~75 years for secondary cutaneous angiosarcoma. Almost all cases in the breast were in women (99.2%), 70.4% of breast angiosarcomas were secondary. At presentation, 60% of primary angiosarcomas and 73% of secondary angiosarcomas presented with local or regional disease. The incidence rate of visceral angiosarcoma is also increasing (1.8% per year; p < 0.01). The most common sites of visceral primary disease were liver (27.5%), heart (17.3%) and bone (12.5%).

Conclusion: This study describes angiosarcoma presentation patterns and incidence in the United States over a 17-year period and shows that the number of cases is increasing, with the greatest rise in women with secondary angiosarcoma of the chest/breast/upper extremity. These data increase awareness of a rare but highly morbid disease and highlight the need for monitoring and increased suspicion of angiosarcoma in patients at higher risk, such as women who have a prior history of breast cancer.