Embryonal rhabdomyosarcoma is the most common type and comprises about 60% of cases.Outcomes vary considerably, with 5 years survival rates between 35% and 95% depending on the type of RMS involved, so clear diagnosis is critical for effective treatment and management. Accurate and quick diagnosis is often difficult due to the heterogeneity of RMS tumors and a lack of strong genetic markers of the disease, although recent research by UVA Health researchers discovered “multiple lines of evidence supporting [the gene] AVIL is powerful driver for both major types of rhabdomyosarcoma,” according to researcher Hui Li, PhD, of the University of Virginia School of Medicine’s Department of Pathology and UVA Cancer Center. (.) Malfunctions in AVIL, Li and his team found, play an essential role in the development of the two main subtypes of rhabdomyosarcoma. In a scientific paper outlining the findings, he and his colleagues describe rhabdomyosarcoma as “addicted” to the gene’s excess activity. They ultimately label AVIL a “bona fide oncogene” for rhabdomyosarcoma. Treatment usually involves a combination of surgery, chemotherapy, and radiation. Sixty percent to 70% of newly diagnosed patients with nonmetastatic disease can be cured using this combined approach to therapy. Despite aggressive multimodality treatment, less than 20% of patients with metastatic RMS are able to be cured of their disease. Types
Given the difficulty in diagnosing rhabdomyosarcoma, definitive classification of subtypes has proven difficult. As a result, classification systems vary by institute and organization. However, rhabdomyosarcoma in the 2020 WHO classification is listed as four histological subtypes: embryonal, alveolar, pleomorphic, and spindle cell/sclerosing.
The fourth IRSG study found that 23% of patients were diagnosed in time for a complete resection of their cancer, and 15% had resection with only minimal remnants of the diseased cells. Risk factors
Rhabdomyosarcoma is difficult to diagnose. Risk factors that increase the likelihood of this cancer include inherited disorders such as Li-Fraumeni syndrome, Neurofibromatosis type 1, Beckwith-Wiedemann syndrome, Costello syndrome, Noonan syndrome, and DICER1 syndrome. Genetic
There are multiple genetic lesions associated with rhabdomyosarcoma, but there has been little consistent data demonstrating an association between specific genetic abnormalities and outcome. However, alveolar and embryonal types of RMS can be distinguished cytogenetically, and identification of specific genetic lesions can allow for accurate classification of the ARMS subtype when the histopathological findings are equivocal or unclear. This is valuable for clinical practice as the alveolar type presents a higher risk to the patient and will often require more aggressive treatment than the embryonal type. Thus, ARMS is also referred to as Fusion Positive rhabdomyosarcoma (FP-RMS). Up to 90% of alveolar RMS cases present with a translocations of t(2;13)(q35, q14) or, less commonly, t(1;13)(p36, q15). Both involve the translocation of a DNA binding domain of either PAX3 or PAX7, a member of the Paired Box family of transcription factors, to a transactivation site on FOXO1 (previously known as FKHR), a member of the forkhead/HNF-3 transcription factor family. The t(2;13) translocation results in a fusion of the PAX3 gene with FOXO1, while the t(1;13) translocation involves the fusion of PAX7 with FOXO1.