Rhabdomyosarcomas account for 7-8% of all childhood malignant solid cancers with fewer than 60 children diagnosed per year (mostly under 10 years of age). It is actually the most common soft tissue sarcoma in children. It has a slightly higher preponderance in males than in females. Rhabdomyosarcomas can occur at any age but approximately 87% of patients are younger than 15 years. Rhabdomyosarcoma rarely affects adults.1
Etiology:
We still do not know what causes most cases of rhabdomyosarcoma (RMS), but researchers are starting to understand how certain changes in DNA can cause normal cells to become cancerous and lead to RMS.2
Signs & Symptoms:
The most common symptom of rhabdomyosarcoma is an asymptomatic mass.3 If symptoms are present, they usually have to do with the associated organs that are effected by the actual mass. For example, tumor of the orbit may cause proptosis or opthalmoplegia. Genitourinary tumors may cause hematuria, obstruction, or constipation. Many times parameningeal tumors cause cranial nerve palsy, headaches, or sinus obstructions.
Diagnostic Procedures:
The recommended procedures for these patients include3:
History
Physical
Laboratory studies
Imaging studies (chest x-ray, CT scan, bone scan, MRI)
Bone marrow biopsy and aspirate
Lumbar puncture
Histology:
Rhabdomyosarcoma is a highly malignant soft tissue sarcoma from unsegmented, undifferentiated mesoderm. The four histologic subtypes of rhabdomyosarcomas include3:
Embryonal
The spindle cell subtype of embryonal rhabdomyosarcoma has a spindled appearance and is often found in paratesticular sites.
Botryoid subtype of embryonal
The botryoid subtype is a polypoid variant of embryonal rhabdomyosarcoma. It is usually noninvasive and localized. It is found in mucosal-lined organs (such as the vagina, urinary bladder, middle ear, biliary tree, and nasopharynx).
Alveolar
Pleomorphic
Lymph node drainage:
Rhabdomyosarcomas may occur in any site in the body.3 The lymph node drainage depends on the disease site. The most frequently involved sites include:
Orbit (9%)
Head and neck (excluding parameningeal tumors) (7%)
Parameningeal (25%)
Genitourinary (31%)
Extremity (13%)
Trunk (5%)
Retroperitoneum (7%)
Other miscellaneous sites (3%)
Metastatic spread:
Lymph node metastases is dependent on the disease sight.3 Around 15% of other head and neck tumors sites, 25% of paratesticular tumors, and 20% of extremity and truncal tumors involve lymphatic spread. Hematogenous is commonly found at the initial presentation of disease in about 15% of patients. The lungs, bone marrow, and bone are the most common places for the hematogenous dissemination.
Grading:
Soft tissue sarcomas are classified as either low-grade or high-grade tumors.4 In low-grade the cancer cells look like the normal cells of the soft tissues. They are usually slow-growing and are less likely to spread. In high-grade tumors the cells look very abnormal. High-grade tumors grow more quickly and are more likely to spread. Embryonal and alveolar types of rhabdomyosarcoma are always high-grade.
Staging:
The clinical grouping classification used by the Intergroup Rhabdomyoscaroma Study (IRS) requires surgical-pathologic evaluation.3
The TNM system is used in pretreatment staging with emphasis on characteristics of the primary tumor, size, invasiveness, nodal status, and systemic spread.
Stage I if the tumor is without hematogenous metastases and is in a favorable site, such as orbit, genitourinary non-bladder-prostate, or head and neck nonparameningeal.
Stage II tumors are unfavorable if primary site is bladder, prostate, extremity, parameningeal, and other sites with smaller than 5 centimeters with negative regional lymph nodes.
Stage III are in an unfavorable primary site, larger than 5 centimeters and node negative or positive.
Since Rhabdomyoscaromas may occur at any site in the body, side effects are going to be specific to the location of disease and to the area of radiation treatment. Toxicity is related to the region irradiated and the dose administered.3 Attention to skin care with moisturizes or steroid cream should be given. In cases where orbital irradiation is given, an acute inflammatory reaction of the cornea and conjunctiva occurs, resulting in pain and photophobia. An ophthalmologist should administer steroids. Other side effects can include: cataracts, dry eye, keratitis, orbital hypoplasia, ptosis and enophthalmos, tissue asymmetry, malformed teeth, impaired vision, acute otitis externa, eustachian tube swelling, erythematous mucositis, acute gastrointestinal sequelae, nausea, vomiting, bone and soft tissue growth disturbances, gypopituitarism, gonadal dysfunction, induction of second malignant tumors, and chronic organ disfunction.3
Prognosis:
Poor prognostic factors include age less than 1 and more than 10 years, aveolar histology, unfavorable primary site, size greater than 5 cm, and higher clinical group.3
Treatments:
A multidisciplinary approach using surgery, irradiation, and chemotherapy is critical to the management of rhabdomyosarcoma.3 Stage I tumors are resected with an adequate margin and require chemo, but generally not radiation. Radiation ports should include soft tissue extent at presentation with margins.
3D conformal treatment is an optimal field arrangement. Radiation doses: Residual disease: 50.4 - 55.8 Gy Combined chemoradiation: 40 - 41.4 Gy Brain or spinal cord: 30 Gy
Orbit: High dose radiation (45-50 Gy) provides good local control, the addition of chemotherapy improves outcomes. Reprinted from Radiation Oncology Management Decisions, 2013.3
Head and Neck (nasopharynx, nasal cavity, paranasal sinuses, middle ear, pterygopalatine fossa and infratemporal fossa): Radiation to local fields with margins. Craniospinal irradiation is necessary with neuraxis dissemination.
Head and Neck (scalp, parotid, oral cavity, larynx, oropharynx, and cheek): Complete surgical resection. Radiation use is based on the extent of residual disease. Draining lymph nodes are not typically irradiated unless metastatic.
Bladder and Prostate: Anterior pelvic exenteration combined with chemotherapy and radiation for residual disease. Partial cystectomy for small tumors arising from the dome of the bladder.
Paratesticular: Early stage disease may be completely resected with good control rates. Regional lymph node irradiation to the periaortic and ipsilateral iliac nodes is recommended. Tumor extension to the scrotum is an indication for irradiation.
Gynecological Tumors (vulva, vagina, cervix, and uterus): Surgery is primarily used for diagnosis, but resection may be possible. Very sensitive to chemotherapy and may not need irradiation for tumor control. Radiation is typically reserved for residual disease after surgical resection. Intracavitary and interstitial brachytherapy is very useful for these tumors.
Other Pelvic Sites (perianal, perirectal, and perineal): Lymph node involvement is common. Chemotherapy and radiation are recommended when exenteration is needed.
Extremities: Complete surgical resection with limb salvage is recommended. Chemotherapy and radiation are recommended for local control.
http://neurosurgeon.pbworks.com/w/page/11047283/Tumors%20of%20the%20Pediatric%20Skull,%20Skull%20Base,%20and%20Orbit
Radiation ports should include soft tissue extent at presentation with margins.
3D conformal treatment is an optimal field arrangement.
Radiation doses:
Residual disease: 50.4 - 55.8 Gy
Combined chemoradiation: 40 - 41.4 Gy
Brain or spinal cord: 30 Gy
Orbit:
High dose radiation (45-50 Gy) provides good local control, the addition of chemotherapy improves outcomes.
Reprinted from Radiation Oncology Management Decisions, 2013.3
Head and Neck (nasopharynx, nasal cavity, paranasal sinuses, middle ear, pterygopalatine fossa and infratemporal fossa):
Radiation to local fields with margins.
Craniospinal irradiation is necessary with neuraxis dissemination.
Head and Neck (scalp, parotid, oral cavity, larynx, oropharynx, and cheek):
Complete surgical resection.
Radiation use is based on the extent of residual disease.
Draining lymph nodes are not typically irradiated unless metastatic.
Bladder and Prostate:
Anterior pelvic exenteration combined with chemotherapy and radiation for residual disease.
Partial cystectomy for small tumors arising from the dome of the bladder.
Paratesticular:
Early stage disease may be completely resected with good control rates.
Regional lymph node irradiation to the periaortic and ipsilateral iliac nodes is recommended.
Tumor extension to the scrotum is an indication for irradiation.
Gynecological Tumors (vulva, vagina, cervix, and uterus):
Surgery is primarily used for diagnosis, but resection may be possible.
Very sensitive to chemotherapy and may not need irradiation for tumor control.
Radiation is typically reserved for residual disease after surgical resection.
Intracavitary and interstitial brachytherapy is very useful for these tumors.
Other Pelvic Sites (perianal, perirectal, and perineal):
Lymph node involvement is common.
Chemotherapy and radiation are recommended when exenteration is needed.
Extremities:
Complete surgical resection with limb salvage is recommended.
Chemotherapy and radiation are recommended for local control.
Brain: 45 Gray (Gy): Necrosis, infarction
Brainstem: 50 Gy: Necrosis, infarction
Parotid: 32 Gy: Xerostomia
Ear: 55 Gy: Chronic serous otitis
Larynx: 45 Gy: Laryngeal edema
Lens: 10 Gy: Cataract needing intervention
Optic chiasm: 50 Gy: Blindness
Optic nerve: 50 Gy: Blindness
Kidney: 23 Gy: Clinical nephritis
Liver: 30 Gy: Liver failure
Small bowel: 40 Gy: Obstruction, perforation, fistula
Colon: 45 Gy: Obstruction, perforation, ulceration, fistula
Bladder: 65 Gy: Contracture and volume loss
Back to Week 6