Rhabdomyosarcoma: A Childhood Soft Tissue Cancer

Rhabdomyosarcoma is a cancer that starts in muscle tissue, most often muscle attached to bone. It is the most common soft-tissue sarcoma in children. It can happen at any age, but children get it most often. With today's treatment, most children with rhabdomyosarcoma do well.

Rhabdomyosarcoma can grow almost anywhere in the body, but some spots are more common than others. Tumors near the head, neck, or the genital and urinary organs are usually embryonal rhabdomyosarcoma, the most common type. Tumors in the arms, legs, chest, or belly are more often alveolar rhabdomyosarcoma, a type that tends to grow and spread faster.

The most common sign is a lump or swelling that keeps growing or does not go away. Depending on where the tumor sits, other signs can include crossed or bulging eyes, headaches, trouble urinating, bowel changes, or unexplained bleeding from the nose, throat, vagina, or rectum. Have your child's doctor check any lump or swelling that persists.

Doctors use imaging tests to see the tumor and check whether it has spread. These can include X-rays, CT scans, MRI, and sometimes PET or bone scans. A biopsy removes a small piece of the tumor, so a pathologist can study it under a microscope. Lab tests on that tissue — including tests that look at chromosomes and specific proteins — confirm the exact type of rhabdomyosarcoma your child has.

Doctors use three pieces of information together to plan treatment.

• Stage describes the tumor's size, location, and whether it has spread, on a 1-to-4 scale.
• Group describes how much tumor is left after the first surgery, from group I (all removed) to group IV (spread to distant sites).
• Risk — low, intermediate, or high — combines stage, group, tumor type, and location. It guides how strong treatment needs to be.

Ask your child's team to explain the stage, group, and risk category in plain terms. All three shape the treatment plan. A low-risk tumor may need less chemotherapy. A high-risk tumor needs a stronger, longer plan.

Every child with rhabdomyosarcoma gets chemotherapy, no matter the risk group. Chemotherapy travels through the bloodstream to kill cancer cells that surgery and radiation cannot reach on their own. Common drugs include vincristine, dactinomycin, and cyclophosphamide, usually combined.

Surgery removes as much of the tumor as it is safe to remove. Sometimes surgery comes first. Other times, chemotherapy shrinks the tumor first, which can make surgery easier and less disfiguring.

Radiation therapy targets cancer cells left behind after surgery, or treats tumors that cannot be fully removed. Whether your child needs radiation depends mostly on the group and how much tumor remains after surgery. A full treatment plan can run many months, so ask your child's team to walk you through it step by step, phase by phase.

Most children with rhabdomyosarcoma in the United States are treated as part of a clinical trial through the Children's Oncology Group. These trials compare the current best treatment against a promising new approach, and joining one does not mean your child gets an unproven treatment instead of standard care — it usually means access to the same standard care, closely monitored, sometimes with an added option.

Some signs cannot wait for a call-back.

• Call 911 or go to an emergency department if your child has trouble breathing, bleeding that will not stop, or is confused, floppy, or hard to wake.
• Call your child's care team straight away, at any hour, if your child has a fever of 100.5°F — 38 °C is 100.4 °F; act at 100.4 °F — or higher during chemotherapy, or shaking chills. NCI treats a fever during treatment as a sign of infection to phone about at once: blood counts are low, and an infection can turn serious within hours. If nobody answers quickly, take your child in and say they are on chemotherapy.
• Call your child's care team the same day if pain is new or getting worse, your child cannot keep fluids down, or a wound or line site turns red, swollen, or sore.
• Call your child's care team within a day or two if eating, energy, or mood changes in a way that worries you between visits.

Ask which type of rhabdomyosarcoma your child has, and which risk group they fall into. Ask what the full treatment plan looks like and how long it will take. Ask whether a clinical trial is open and appropriate. Ask what side effects to expect, and exactly how the team will manage them.

Follow-up does not end when chemotherapy or radiation stops. Your child's team will schedule regular checkups, scans, and blood tests to watch for the cancer coming back. These visits usually happen often at first, then space out over time. Ask for a written summary of your child's treatment. It should list every drug and dose, and any radiation given, since this record matters for care later in life.

• National Cancer Institute — Childhood Rhabdomyosarcoma Treatment (PDQ).
• National Cancer Institute — Infections in People with Cancer.