Angiosarcoma

Angiosarcoma is a type of cancer that begins in the cells that line the blood vessels or lymph vessels. It is a type of soft-tissue sarcoma, which are solid tumors that begin in tissues that connect, support, or surround organs and other body tissue. Angiosarcoma is very rare — occurring in only about two people per million. It is more common in adults than children, and it is treated differently in adults than children. The tumor behaves differently in each person. All angiosarcomas need aggressive evaluation and treatment.

Angiosarcoma is a type of vascular tumor. The World Health Organization (WHO) classifies vascular tumors into three types: benign, intermediate (either locally aggressive or rarely metasticizing), and malignant. Angiosarcoma fits into that third category — malignant (cancerous). It is one of the most difficult types of vascular tumor to treat.

As a type of cancer, angiosarcoma is also classified according to the following stages:

• Stage 1: the tumor is relatively small and contained within the area where it started.
• Stage 2: the angiosarcoma has not started to spread into surrounding tissue but it is larger than in stage 1. (Both stage 1 and stage 2 are considered low-grade.)
• Stage 3: the angiosarcoma tumor is larger and has started to spread into surrounding tissues.
• Stage 4: the angiosarcoma has spread from where it started to other organs or sites in the body. This is called metastatic cancer. (Stage 3 and 4 are high-grade tumors.)

Angiosarcoma can appear anywhere in the body. Common sites in adults are in the head and neck region. In children, angiosarcoma can arise on the skin, deep tissues, or internal organs. The tumor can spread to the lung, liver and bone.

The tumor behaves differently in each person. Usually it is very aggressive, but some tumors are low-grade (do not appear as aggressive under the microscope). All angiosarcomas need aggressive evaluation and treatment.

The cause of angiosarcoma is currently unknown, although genetic mutations recently have been identified in adult patients; scientists are now searching for therapies that target these mutations. In adults, angiosarcoma can arise after exposure to chemicals or radiation, or in long-standing ulcerations and lymphedema. Though very rare, angiosarcomas in children have been reported to arise in vascular anomalies and hemangiomas of the liver.

The first step in treating your child is forming an accurate and complete diagnosis. Your child’s treatment team may order a number of different diagnostic tests for angiosarcoma, including:

• Blood and urine tests
• Ultrasound
• Magnetic resonance imaging (MRI)
• Bone scans or PET scan
• Computerized tomography scan (CT or CAT scan)
• Biopsy

There may be other diagnostic tests that your doctor will discuss with you depending on your child's individual situation. After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. We will then meet with you and your family to discuss the results and outline the best possible treatment options.

Because angiosarcoma is often misdiagnosed as a hemangioma or other benign tumor, if you suspect your child may have received an incorrect diagnosis, it is worth seeking a second opinion. Our treatment team includes one of the few pathologists with specialized expertise in pediatric vascular tumors, including how to differentiate between angiosarcoma and other vascular tumors. An accurate diagnosis is key to forming the best possible treatment plan. Any skin lesions that do not go away, get larger and are noted after the age of 6 months should be investigated by a vascular specialist. Any liver lesion that enlarges during “hemangioma” therapy also should be evaluated by an expert.

Your child's treatment team will determine a specific course of angiosarcoma treatment based on several factors, including your child's age, overall health and medical history and the type, location, and size of the angiosarcoma. Angiosarcoma treatment options include:

• Surgery
• Chemotherapy
• Radiation therapy

For high-grade angiosarcoma, treatment may also include biologic agents, usually angiogenesis inhibitors — medications that inhibit the growth of new blood vessels. Sometimes, these medications can shrink the tumor further.

Children with relapsed angiosarcoma (the tumor returns) or refractory angiosarcoma (the tumor doesn’t fully go away despite treatment) may be eligible for clinical trials that test new treatment options.

The prognosis for children with localized (stage 1) angiosarcoma that can be completely surgically removed is good. However, for children with advanced angiosarcoma, the prognosis remains poor. As physician scientists learn more about the genetic underpinnings of angiosarcoma, and seek to develop drugs that target specific mutations, the hope is the prognosis will improve.

Because angiosarcoma is so rare, very few doctors have experience diagnosing and treating it. The Vascular Anomalies Center at Boston Children's Hospital, in partnership with the Dana-Farber/Boston Children's Cancer and Blood Disorders Center Solid Tumor Center, has evaluated more children with angiosarcoma and other rare vascular tumors than any other hospital in the world. Our physicians — representing 16 medical and surgical specialties, including radiologists and pathologists who specialize in diagnosing vascular anomalies — take an interdisciplinary approach to care with every child we see.

Our physicians — representing 16 medical and surgical specialties, including radiologists and pathologists who specialize in diagnosing vascular anomalies — draw on those experiences to continually refine the therapies and achieve better long-term outcomes for children with angiosarcoma. Our team takes an interdisciplinary approach to care with every child we see. On your child’s first visit, your child likely will be evaluated by a whole treatment team at the same time. From there, the team works with you to develop and carry out a comprehensive and coordinated care plan that matches your child's specific needs.

We also can provide care to angiosarcoma patients from afar, seeing the child in person on an infrequent basis but coordinating closely with providers closer to home.

Both Dana-Farber Cancer Institute and Boston Children's Hospital are among the top pediatric research centers in the world for pediatric tumors and vascular anomalies. Our research programs include laboratory scientists and clinical researchers.

Much of our current angiosarcoma research is focused on trying to better understand the genetic underpinnings of angiosarcoma. The physician scientists in our programs provide free on-site genomic sequencing of all angiosarcoma tumors (using samples of tissues obtained during biopsy). Genomic sequencing can help provide insights into complex diseases by finding common genetic variants (mutations) shared between the individuals with the disease. Once the specific mutations are discovered, it may then be possible to develop drugs that can counteract those mutations. Ultimately, someday we may be able to treat angiosarcoma without needing surgery, instead using precision medicine.

Currently, the genomic sequencing is being performed primarily to increase scientific knowledge. However, if an individual’s test reveals information that could be of clinical benefit, those results will be shared with your referring physician for discussion with you and your child.

For many children with rare or hard-to-treat conditions such as angiosarcoma, clinical trials provide new options. We have a large portfolio of early phase (phase 1 or 2) clinical trials that may be an option for children with relapsed or refractory solid tumors, including angiosarcoma.