87 New research has found that the incidence of angiosarcoma, a rare and aggressive form of cancer, has doubled in the US over the past two decades. The study, which examined data from 2001 to 2020, highlights a worrying trend, particularly among women who have previously undergone treatment for breast cancer. The findings were published in the journal JAMA Network Open. Angiosarcoma, a type of cancer that originates in the lining of blood vessels and lymphatic vessels, often presents either as a primary cancer or as a secondary malignancy following radiotherapy. The latest findings provide an important insight into the disease’s prevalence and characteristics, as well as the demographic groups most affected. Between 2001 and 2019, the annual incidence of angiosarcoma in the US grew steadily, from 657 cases in 2001 to 1,312 in 2019. This represents a 1.6% increase per year in the adjusted incidence rate, reaching 3.3 cases per one million person-years. The Covid pandemic, however, caused some disruption in 2020, which resulted in a slight decline in the number of cases reported that year to 1,159. A significant proportion of the rise in cases has been linked to secondary angiosarcoma, particularly among women. The study found that women with a history of breast cancer were at heightened risk of developing secondary angiosarcoma, especially in the chest wall or upper extremities, where radiotherapy is often used as part of cancer treatment. The connection between angiosarcoma and prior breast cancer treatment is one of the key findings of the study. Among women diagnosed with breast angiosarcoma, 71.9% were classified as secondary cases, meaning they developed angiosarcoma after receiving treatment for breast cancer. In contrast, the majority of cases in men were primary, unrelated to previous cancer therapies. The risk appears particularly high for women who have undergone radiotherapy. The data suggests that secondary angiosarcoma can develop many years after breast cancer treatment, prompting concerns about the long-term effects of radiotherapy. Although breast conservation techniques have become more widespread, they still carry the potential risk of developing angiosarcoma in the irradiated areas. In addition to cutaneous and breast angiosarcomas, the study also identified an increase in visceral angiosarcomas, which occur in internal organs such as the liver, heart, and bones. While these cases are rarer, their incidence is increasing at a similar rate to that of cutaneous angiosarcomas. In 2020, visceral angiosarcomas made up approximately 24.4% of all cases, with the liver and heart being the most commonly affected organs. Patients diagnosed with visceral angiosarcomas tend to be younger than those with cutaneous forms of the disease, with a median age of 65 compared to 71 for those diagnosed with skin angiosarcoma. But survival outcomes for visceral angiosarcomas are typically poor due to the difficulty in detecting the disease at an early stage. The growing body of evidence linking radiotherapy to secondary angiosarcoma raises important questions about the balance between the benefits and risks of cancer treatment. While radiotherapy remains an effective tool in the fight against breast cancer, its potential to cause secondary malignancies such as angiosarcoma must be carefully considered. Experts suggest that newer radiotherapy techniques, which minimise exposure to surrounding healthy tissue, could help reduce the risk of developing secondary angiosarcomas in the future. Additionally, there are calls for increased monitoring of breast cancer survivors who have undergone radiotherapy, in order to detect any early signs of angiosarcoma. As angiosarcoma is a rare and highly aggressive cancer, the development of new treatment strategies tailored to the specific molecular characteristics of the disease is crucial. Continued research and clinical trials will be crucial in enhancing outcomes for those suffering from this devastating illness because the incidence of the disease is rising, particularly among those with a history of cancer.