According to the Institute of Cancer Research (ICR), a collaborative pilot study spearheaded by the Institute found that liquid biopsies could aid in the management, care, and treatment of pediatric rhabdomyosarcoma. Early diagnosis and treatment are crucial for improving patient outcomes. Within this study, published in the Journal of Clinical Oncology – Precision Oncology, the research team found that liquid biopsies could predict disease severity and treatment response.

Liquid Biopsies (and What They’ve Shown)

To begin, let’s explore what a liquid biopsy is. The National Cancer Institute (NCI) explains that:

Different liquid biopsy tests analyze different kinds of tumor material, such as DNA, RNA, proteins, tiny vesicles called exosomes, and whole cells. The tests detect these molecules or cells in various bodily fluids, including blood, urine, cerebrospinal fluid, or saliva.

For this study, researchers began by studying mice models of rhabdomyosarcoma. After performing liquid biopsies, the researchers found that they were able to identify tumors and monitor tumor growth using circulating tumor DNA. Next, the research team sourced tissue and blood samples from 28 pediatric patients with rhabdomyosarcoma. They then performed liquid biopsies to assess the cancer. Findings include:

• Of those who had provided blood samples, 77% had cancerous genetic changes. For example, some patients had TP53 or MYOD1 gene variants, which are linked to faster cancer progression and worse outcomes. Researchers believe that identifying these variants could help doctors learn who to treat more aggressively.
• Those whose cancer had metastasized had higher levels of cancer DNA in the bloodstream. Additionally, those whose cancer was in more difficult-to-treat areas also had higher levels of cancer DNA.
• Higher levels of circulating tumor DNA could predict those who may need more treatment or who are responding or may respond poorly to treatment.

Researchers do acknowledge that their study consisted of a smaller number of patients. Though the data does show promise, additional research is needed. Currently, the research team hopes to launch an international clinical study by the end of the year to further assess the efficacy and potential use of liquid biopsies for rhabdomyosarcoma management.

About Rhabdomyosarcoma

Rhabdomyosarcoma is a rare form of sarcoma which develops in soft tissue. While this cancer can form anywhere in the body, it most often begins in the arms, legs, head, neck, or urinary or reproductive systems. Rhabdomyosarcoma can affect people of all ages. However, this cancer is most commonly found in children and adolescents. Risk factors include certain genetic conditions like Noonan syndrome or Costello syndrome or having a family history of cancer. Symptoms of rhabdomyosarcoma vary based on where the cancer is located. Potential symptoms can (but do not always) include:

• Bulging or swelling eyes
• Headaches
• Ear, nose, and throat bleeding
• A lump that grows or doesn’t go away
• Difficulty urinating or passing bowel movements
• Hematuria (blood in the urine)
• Vaginal or rectal masses or bleeding
• Pain in the affected area