Most cases of rhabdomyosarcoma occur sporadically, with no recognized predisposing factor or risk factor. For patients with embryonal tumors, high birth weight and large size for gestational age are associated with an increased incidence of rhabdomyosarcoma. Genetic conditions associated with rhabdomyosarcoma include Li-Fraumeni cancer susceptibility syndrome (with germline p53 mutations),[14,15,16] neurofibromatosis type I, Costello syndrome (with germline HRAS mutations),[18,19,20] Beckwith-Wiedemann syndrome (with which Wilms tumor and hepatoblastoma are more commonly associated),[21,22] Noonan syndrome, and MEN2A.
The prognosis for a child or adolescent with rhabdomyosarcoma is related to the age of the patient, site of origin, widest diameter of the tumor, resectability, presence of metastases, number of metastatic sites or tissues involved, presence or absence of regional lymph node involvement, histopathologic subtype (alveolar vs. embryonal), and delivery of radiation therapy (RT) in selected cases,[7,8,25,26,27,28,29,30,31]; [Level of evidence: 3iiiA] as well as unique biological characteristics of rhabdomyosarcoma tumor cells. It is unclear whether response to induction chemotherapy, as judged by anatomic imaging, correlates with the likelihood of survival in patients with rhabdomyosarcoma, as one study found an association and another study did not.[Level of evidence: 3iiA];  Examples of both clinical and biological factors with proven or possible prognostic significance are briefly described below.