Rhabdomyosarcoma

In addition to a physical examination, the following tests may be used to diagnose rhabdomyosarcoma:
 * Epidemiology: || 250 cases per year which equates to an incidence of 6 cases per 1 million people. Occurrence is slightly higher i males than in females. 87% of patients are less than 15 years of age and 13% if patients are 15-21 years of age. 1 This sarcoma may present at any site within the body with the major ones being: orbit - 12%, hand and neck (excluding parameningeal tumors) - 16%, parameningeal tumors - 11%, genitourinary tract with bladder and prostate - 11%, genitourinary tract without bladder and prostate - 17%, extremities - 17% and miscellaneous sites - 16%. 2 With involvement of the genitourinary tract the predominance is 3 to 1 males versus females for bladder or prostate sites. The rest of the genitourinary tract has a predominance of 2 to 1 males versus females. For sites in the extremities, the predominance is slightly higher for females versus males and the same is true for a primary site in the orbit. 3 ||
 * Etiology: || The cause of rhabdomyosarcoma is unknown. Research is focusing on genetic syndromes, congenital abnormalities and environmental factors. 4 ||
 * Signs & Symptoms: || Signs & symptoms at presentation are as follows: at many sites the lesion presents as an asymptomatic mass or the symptoms are related to the mass effect caused by the tumor. Rhabdomyosarcoma in the orbit could cause proptosis and opthalmoplegia. Tumors in the parameningeal region could present with cranial nerve palsy, headache and nasal, aural or sinus obstruction. 5 ||
 * Diagnostic Procedures: ||
 * Biopsy.** A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The type of biopsy performed will depend on the location of the cancer. If the tumor is near the surface of the body, the child will be given a local anesthetic to numb the area during the procedure; if it is deeper inside the body, a general anesthetic will be used. The sample removed during the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).
 * Immunocytochemistry tests.** These are special stains done on the cells taken during the biopsy to help the doctor make an accurate diagnosis of rhabdomyosarcoma . Stains that show muscle cell development, including MyoD-1 and Myogenin, are most helpful.
 * Genetic tests of tumor tissue.** Changes in certain chromosomes (structures that contain the genes in a cell) in the tumor cells, called chromosomal translocations, can help doctors identify the alveolar subtype of rhabdomyosarcoma, although some alveolar rhabdomyosarcomas lack any specific translocation. Doctors will do a genetic test of the tumor tissue to see if translocations have occurred. 6

To determine where the cancer is located and if it has spread, the doctor may use the following imaging tests: Investigators have observed a subset of patients with a solid alveolar pattern, considered a subtype of alveolar rhabdomyosarcoma Based on a review of data, which divides subgroups into distinct prognostic groups. The botryoid subtype, a polypoid variant of embryonal rhabdomyosarcoma, has a grapelike appearance; it is usually noninvasive and localized, and presents in mucosal-lined organs such as the vagina, urinary bladder, middle ear, biliary tree, and nasopharynx. The spindle cell subtype of embryonal rhabdomyosarcoma has a spindled appearance and is frequently found in paratesticular sites. Patients with embryonal rhabdomyosarcoma have intermediate outcome; the mesenchymal cells tend to differentiate into cross striated muscle cells. Immunohistochemistry may demonstrate actin- or desmin positive reactions. Ultrastructural studies exhibit evidence of myogensis. The presence of cross striations confirms the diagnosis. The poor prognosis group includes alveolar and undifferentiated sarcomas. 7
 * Imaging tests **
 * X-ray.** An x-ray is a picture of the inside of the body. These pictures can help detect tumor growth in the bones or lungs and distortion of soft tissue caused by a large tumor.
 * Computed tomography (CT or CAT) scan.** A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into the patient’s vein to provide better detail.
 * Magnetic resonance imaging (MRI).** An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
 * Bone scan.** A bone scan uses a radioactive tracer to look at the inside of the bones. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears gray to the camera, and areas of injury, such as those caused by cancer, appear dark.
 * Positron emission tomography (PET) scan.** A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images. 6 ||
 * Histology: || The classic classification of rhabdomyosarcoma, consists of four histological subtypes: embryonal, botryoid subtype of embryonal, alveolar, and pleomorphic.

Each rhabdomyosarcoma tumor is classified as either favorable or unfavorable based on its histology, which is what the cells look like under a microscope. The terms “favorable” and “unfavorable” refer to the appearance of the cancer cells. In general, the more cancer cells look like normal cells, the more “favorable” they are. Favorable histology tumors include the following: **Embryonal rhabdomyosarcoma.** This is the most common type of rhabdomyosarcoma, frequently found in the head and neck and in the reproductive and urinary organs. Unfavorable histology tumors include the following: **Alveolar rhabdomyosarcoma.** This is a more aggressive type of rhabdomyosarcoma, found most often in the arms, legs, or trunk of the body. are rare from orbital tumors occur in 15% of other head and neck sites, usually metastasizing to the nasopharynx occur in 25% of paratesticular tumors occur in 20% of extremity and truncal tumors 10
 * Botryoid rhabdomyosarcoma.** This is one subtype of embryonal rhabdomyosarcoma, found most often in hollow organs, such as the bladder and vagina.
 * Spindle rhabdomyosarcoma.** This is another subtype of embryonal rhabdomyosarcoma, found most often in the area around the testicles.
 * Pleomorphic and undifferentiated rhabdomyosarcoma.** These are the rarest types of rhabdomyosarcoma, found most commonly in the arms, legs, or trunk. 8 ||
 * Lymph Node Drainage: || In the head and neck site, patients present with regional lymph node spread. In paratesticular site, regional lymph node spread may occure in the periaortic and ipsilateral iliac, and inguinal nodes. 9 ||
 * Metastatic Spread: || Lymph node metastases:

Hematogenous metastases are found in 15% of patients at presentation, and common sites include lungs, bone marrow, liver, brain, muscle, and breast. 10 || Group 1 Localized ideas, completely resected A Confined to organ or muscle of origin B Infiltrated outside organ or muscle of origin; regional nodes not involved Group II Compromised or regional resection A Grossly resected tumor with microscopic residual disease B Regional disease, completely resected, in which nodes may be involved or extension of tumor into adjacent organ may exist C Regional disease with involved nodes, grossly resected, but with evidence of microscopic residual disease Group III Incomplete resection or biopsy with gross residual disease Group IV Distant metastases at diagnosis. 10 || Radiation therapy techniques - Orbit: Tumor volume includes the entire orbit if irradiation is used. The site of tumor involvement with a margin is treated using doses of 45 to 50 Gy with systemic chemotherapy Parameningeal sites - Head and neck: Irradiation with local-fields plus a margin can provide local tumor control. Patients with known dissemination through out the neuraxix should receive craniospinal irradiation. Head and neck Nonparameningeal sites: Radiotherapeutic management is based on amount of residual tumor after surgery. *Adequate irradiation requires careful attention to volume and dose. Treatment portals encompass the involved region at initial presentation (before chemotherapy) with margins that include surgical sites and biopsy tracts. It is usually sufficient to treat the tumor volume with a 2cm margin without irradiating the whole muscle compartment or the entire muscle from origin to insertion. In patients with tumors of the parameningeal sites (middle ear, paranasal sinuses, nasopharynx, nasal cavity, infratemporal fossa, and parapharyngeal area) it is important to include the adjacent meninges to prevent meningeal relapse. Technique is very important in minimizing corneal and lacrimal gland dose and preserving useful vision in the treated eye. The use of beam shaping devices and corneal and lens protection have proven beneficial. Three-dimensional conformal therapy is optimal for localizing the target volume and sparing normal tissue. As part of a multimodality approach. Irradiation doses of 40.0 to 41.4 Gy given in 4.5 weeks provides 90% local control of microscopic disease, whereas 50.4 to 55.8 Gy (1.5-1.8 Gy daily fractions) in 5.5 to 6 weeks is recommended for gross residual disease. Dose for brain and spinal cord axis is 30 Gy in 1.5 to 2.0 fractions. Interstitial irradiation may play an important role as a primary treatment or boost. Brachytherapy alone or with external-beam irradiation offer excellent tumor control with acceptable morbidity. 11 || 15 || __**References**__ 1. Cripe TM. //Rhabdomyosarcoma//. Available at: [|//http://emedicine.medscape.com/article/988803-overview]//.// Accessed February 11, 2010. 2. Chao KS, Perez CA., Brady LW. //Radiation Oncology - Management Decisions//. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002:657. 3. Cripe TM. //Rhabdomyosarcoma//. Available at: [|//http://emedicine.medscape.com/article/988803-overview]//.// Accessed February 11, 2010. 4. Cripe TM. //Rhabdomyosarcoma//. Available at: [|//http://emedicine.medscape.com/article/988803-overview]//.// Accessed February 11, 2010. 5. Chao KS, Perez CA., Brady LW. //Radiation Oncology - Management Decisions//. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002:657. 6. [|www.cancer.net/Cancer+Types/Rhabdomyosarcoma.com] Accessed Febuary 12, 2010 7. Chao KS, Perez CA., Brady LW. Radiation Oncology- Management Decisions. 2nd edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002. pg 659,661-662 8. [|www.cancer.net/Cancer+Types/Rhabdomyosarcoma.com] Accessed Febuary 12, 2010 9. Chao KS, Perez CA., Brady LW. Radiation Oncology- Management Decisions. 2nd edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002. pg 659,661-662 10. Chao KS, Perez CA, Brady LW. //Radiation Oncology-Management Decisions.// 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002 11. Chao KS, Perez CA, Brady LW. Radiation Oncology-Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002 12. Hand CM, Kim SJW, Waldow SM. Overview of radiobiology. In: Washington CM, Leaver D, eds. //Principles and Practice of Radiation Therapy//. 2nd ed. St. Louis, MO: Mosby; 2004:80-81. 13. Kehwar TS, Sharma SC. Use of normal tissue tolerance doses into linear quadratic equation to estimate normal tissue complication probability. Available at: http;//www.rooj.com/Normal%20Tissue%20/Comp.htm. Accessed February 12, 2010. 14. Hand CM, Kim SJW, Waldow SM. Overview of radiobiology. In: Washington CM, Leaver D, eds.// Principles and Practice of Radiation Therapy//. 2nd ed. St. Louis, MO: Mosby; 2004:80-81. 15. Lenhard,E. Raymond. Jr.,MD., Osteen, T. Robert, Gansler,Ted,.MD. The American Cancer Society's Clinical Oncology. 1st edition. Atlanta,GA. 2001. Pictures.pg 586
 * Grading: || No separate grading system is documented ||
 * Staging: || Intergroup Rhabdomyosarcoma Study staging system
 * Radiation Side Effects: || Renal and electrolyte imbalance demand close monitering from more aggresive therapies that include cisplatin, dacarbazine, etoposide, and other agents. 1 Radiation toxicity is related to the dose and region irradiated. An acute inflammatory reaction of the cornea and conjunctiva resulting in pain and photophobia after orbital irradiation. Cataracts, dry eye, chronic keratitis, orbital hyperplasia; ptosit and enophthalmos are also side effects. In children with nonorbital soft tissue sarcomas of the head and neck displayed hypoplasia or tissue asymmetry, poor dentition or malformed teeth, impaired vision, decreased learning, and some children required growth hormone injections. Scute otitis externa or media with hyperemia and swelling of the membranes of the eustachian tubes is common during or soon after head and neck irradiation. Erythematous mucositis also occurs after head and neck irradiation and after drug therapy. Acute gastrointestinal sequelae such as vomiting and diarrhea are usually managed by supportive care and appropriate medication. Late effects are related to the irradiated site, the dose, and the age of the child at age of treatment. These effects include bone and soft tissue growth disturbances, catared, hypopituitarism, gonadal dysfuntion, induction of second malognant tumors (particularly bone sarcomas), and chronic orgin dysfunction. 11 ||
 * Prognosis: || Poor prognostic factors include tumor larger than 5cm, alveolar or undifferentiated histology, primary tumor site, and treatment modalities. 11 ||
 * Treatments: || A multidisciplinary approach using surgery, irradiation and chemotherapy is critical in the management of rhabdomysarcoma.
 * TD5/5: || The TD5/5 would depend completely upon the major organs at risk at the site of the presentation of the tumor. A few of the major ones would be: the orbit: retina - 55 Gy, Cornea - 50 Gy, Lens - 500 cGy. 12 Optic nerve - average of 50 Gy and the optic chiasm - average of 50 Gy, all of which could result in blindness. 13 For extremities: bone marrow - aplasia and pancytopenia at 250 cGy for the whole organ and 3000 cGy for partial organ. Muscle (child) - atrophy 20-30 Gy for the whole organ and muscle (adult) - fibrosis 60 Gy to the whole organ. Of importance is lymphatic drainage from the extremities. Lymph system - atrophy and sclerosis at 50 Gy to the whole node. For genitourinary sites: bladder - contracture at 60 Gy, vagina - ulcer and/or fistula at 90 Gy, uterus - stricture at 75 Gy and, if unshielded, ovaries - sterilization at 200-300 cGy and testes - sterilization at 100 cGy. 14  ||
 * Treatment Plan and Fields || [[image:scan0004.jpg width="292" height="340" caption="Figure 1 "]]