Rhabdomyosarcoma (RMS) is the most common soft tissue cancer (approximately 60%) in children and adolescents (5% of all pediatric solid tumors). However, it remains a rare cancer with about a hundred cases recorded in France per year. It occurs at all ages with a peak incidence between 2 and 5 years.
RMS develops from skeletal muscle tissues (which ensure walking or maintaining posture) or from precursor cells that will form new muscle fibers.
There are two main types of RMS:
- Embryonal RMS: It accounts for nearly 80% of RMS cases and is generally diagnosed in children under 10 years old. It most commonly appears in the head and neck region, as well as in the genitourinary system.
- Alveolar RMS: Representing about 20% of cases, it occurs more frequently in older children and adolescents. It mainly affects the muscles of the limbs (arms and legs), the trunk (thorax and abdomen), and the anal region.
Main Symptoms
In most children, the first manifestation of this cancer is the appearance of a mass that gradually enlarges and may become sensitive or even painful. Since the primary mass can be located in various parts of the body, the symptoms can be multiple, non-specific, and dependent on the location:
- Eyes: Tearing, swollen or drooping eyelid, strabismus, redness around the eye, bulging eye.
- Head and Neck: Facial asymmetry, vision problems, swollen face, headaches, or ear pain.
- Nose and Throat: Nasal congestion, voice changes, or nasal discharge containing mucus and pus.
- Genital or Urinary Tract: Abdominal pain, difficulty urinating, blood in the urine.
RMS can spread within the body from the primary tumor (metastasis). The patient may then also present a general deterioration of health (fatigue, weight loss, loss of appetite), pain, or signs related to the compression exerted by the metastases on other organs. At the slightest doubt, do not hesitate to make an appointment with your general practitioner who will refer the child for appropriate diagnostic tests.
Diagnosis
Rhabdomyosarcoma can occur in almost any anatomical site, but the most common locations are in the head and neck region and in the urinary system.
- Intraorbital RMS: These are diagnosed early by observing a displacement of the eyeball in the orbit. The eye is then often off-center.
- Head and Neck RMS: These tumors are often recognized after a prolonged period of nasal obstruction. They are frequently associated with bone involvement at the base of the skull. They can then be revealed by cranial nerve paralysis and extend to the meninges.
- Urinary System Tumors: Bladder and prostate tumors can manifest through urinary retention or repeated urinary infections.
- Some RMS are diffusely present from the start: This is most often an adolescent with a limb tumor. The patient then presents with general health deterioration, fever, anemia, bleeding, and diffuse bone pain. The tumor may be small or even undetectable. Bone marrow cell examination allows for diagnosis and elimination of acute leukemia, which is most often suggested by these symptoms.
The diagnosis of RMS is confirmed by imaging and pathology. On CT and/or MRI, the tumor appears solid, often poorly defined, and with necrosis. In areas where RMS is common (head and neck, urinary system), this diagnosis is suggested and will be confirmed by biopsy. In other rarer locations, multiple diagnoses can be discussed. The child or adolescent will be referred as soon as possible to a multidisciplinary pediatric oncology team where the diagnosis will be confirmed after the biopsy, which will allow for necessary histological and biological analyses. Biopsy is therefore essential and must be performed in a specialized center by an expert team to ensure the biopsy is well executed (and to avoid tumor rupture or dissemination).
Treatments
The main goal of RMS treatment is to achieve local control of the tumor. Indeed, when these tumors are not metastatic at diagnosis, they present a high risk of local recurrence. Moreover, since half of the patients are under 5 years old, monitoring and prevention of sequelae must be thorough, especially as local treatment can expose the child to sequelae that will worsen with growth.
- Surgery: Tumor removal will only be proposed as the first treatment if it can be complete and without functional consequences. It is therefore mainly proposed for small, easily accessible tumors.
- Chemotherapy: It is essential, and in RMS treatment, several medications are effective and used in combination. IVA cures (ifosfamide, vincristine, and actinomycin) are the most used. Maintenance chemotherapy, given after IVA chemotherapy, has recently shown its benefit for RMS with a higher risk of recurrence.
- External Radiotherapy: Alone or in addition to surgery, radiotherapy is used to consolidate local tumor control. Radiologists limit the extent of the irradiated area as much as possible to limit sequelae, but it remains sufficiently broad to not increase the risk of recurrence. Various external radiotherapy techniques are possible (proton therapy, conformational irradiation, etc.) and chosen for each patient to be most effective while sparing healthy tissues as much as possible.
- Brachytherapy: Irradiation by brachytherapy is performed by implanting radioactive materials (iridium wires) in or near the tumor. It is a very valuable technique as it delivers radiation to a very small volume at a high dose, thus reducing the risk of sequelae. However, it can only be used for easily accessible (vagina, bladder, prostate, limbs, walls) and small volume (< 5 cm) tumors. To perform this highly specialized treatment, children must be referred to a reference center.
Research Against Rhabdomysarcoma with Imagine for Margo
Since 2011, Imagine for Margo has made cancer research for children, adolescents and young adults its top priority. Faced with the current situation, the association is funding a number of research programs aimed at curing more and better young people affected by cancer.
In 13 years, Imagine for Margo has become a major player in pediatric oncology on a national scale and an influential player in Europe. The association has raised over 20 million euros to co-finance 61 cutting-edge research programs, resulting in 69 new therapies benefiting over 7,200 children in Europe. At the same time, the association carries out numerous welfare initiatives in pediatric oncology departments and supports over 500 families.
If you’d like to help research and build a world with cancer-free children, please click here to make a donation, or visit our “help us” page to find out how you can get involved. Every gesture is essential in our fight for life.
Together, we can beat childhood and adolescent cancer.
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