Table 5. Radiation Therapy (RT) Dose According to Rhabdomyosarcoma Group, Histology, and Site of Disease (Children's Oncology Group [COG]) continued...
Primary sites for childhood rhabdomyosarcoma within the genitourinary system include the paratesticular area, bladder, prostate, kidney, vulva, vagina, and uterus. Specific considerations for the surgical and radiotherapeutic management of tumors arising at each of these sites are discussed in the paragraphs below.
Lesions occurring adjacent to the testis or spermatic cord and up to the internal inguinal ring should be removed by orchiectomy with resection of the spermatic cord, utilizing an inguinal incision with proximal vascular control (i.e., radical orchiectomy). Resection of hemiscrotal skin is required when there is tumor fixation or invasion, or when a previous transscrotal biopsy has been performed. For patients with incompletely removed paratesticular tumors that require RT, temporarily repositioning the contralateral testicle into the adjacent thigh prior to scrotal radiation therapy may preserve hormone production.[Level of evidence: 3iiiC]
Paratesticular tumors have a relatively high incidence of lymphatic spread (26% in IRS-I and IRS-II), and all patients with paratesticular primary tumors should have thin-cut abdominal and pelvic CT scans with contrast to evaluate nodal involvement. For patients who have Group I disease, are younger than 10 years, and in whom CT scans show no evidence of lymph node enlargement, retroperitoneal node biopsy/sampling is unnecessary, but a repeat CT scan every 3 months is recommended.[79,80] For patients with suggestive or positive CT scans, retroperitoneal lymph node sampling (but not formal node dissection) is recommended, and treatment is based on the findings of this procedure.[3,27,81] A staging ipsilateral retroperitoneal lymph node dissection is currently required for all children 10 years and older with paratesticular rhabdomyosarcoma on COG-STS studies. However, node dissection is not routine in Europe for adolescents with resected paratesticular rhabdomyosarcoma. Many European investigators rely on radiographic rather than surgical-pathologic assessment of retroperitoneal lymph node involvement.[77,79] It appears, however, that the ability of the CT scan to predict the presence of lymph node involvement needs further study.
Bladder preservation is a major goal of therapy for patients with tumors arising in the bladder and/or prostate. Two important reviews provide information about the historical, current, and future treatment approaches for patients with bladder and prostate rhabdomyosarcomas.[83,84]
In rare cases, the tumor is confined to the dome of the bladder and can be completely resected. Otherwise, to preserve a functional bladder in patients with gross residual disease, chemotherapy and RT have been used to reduce tumor bulk,[85,86] followed, when necessary, by a more limited surgical procedure such as partial cystectomy. Early experience with this approach was disappointing, with only 20% to 40% of patients with bladder/prostate tumors remaining alive and with functional bladders 3 years following diagnosis (3-year OS was 70% in IRS-II).[87,88] The later experience from IRS-III and IRS-IV, which used more intensive chemotherapy and RT, showed 55% of patients alive with functional bladders at 3 years postdiagnosis, with 3-year OS exceeding 80%.[86,89,90] Patients with a primary tumor of the bladder/prostate who present with a large pelvic mass resulting from a distended bladder caused by outlet obstruction at diagnosis receive RT to a volume defined by imaging studies following initial chemotherapy to relieve outlet obstruction. This approach to therapy remains generally accepted, with the belief that more effective chemotherapy and RT will continue to increase the frequency of bladder salvage.