Table 5. Radiation Therapy (RT) Dose According to Rhabdomyosarcoma Group, Histology, and Site of Disease (Children's Oncology Group [COG]) continued...
With rhabdomyosarcoma of the biliary tree, total resection is rarely feasible and standard treatment includes chemotherapy and RT. Outcome for patients with this primary site is good despite residual disease after surgery. External biliary drains significantly increase the risk of postoperative infectious complications. Thus, external biliary drainage is not warranted.
Patients with rhabdomyosarcoma arising from tissue around the perineum or anus usually have advanced disease. These patients have a high likelihood of regional lymph node involvement, and about half of the tumors have alveolar histology. The current recommendation is to sample the regional lymph nodes. When feasible and without unacceptable morbidity, removing all gross tumor prior to chemotherapy improves the likelihood of cure. In Intergroup Rhabdomyosarcoma Study Group (IRSG) Protocols I through IV, the OS rate after aggressive therapy for 71 patients with tumors in this location was 49%, best for patients in Stage 2 (small tumors, negative regional nodes), intermediate for those in Stage 3, and worst for those in Stage 4 at diagnosis. However, with the goal of organ preservation, patients with tumors of the perineum/anus are preferentially managed with chemotherapy and RT without aggressive surgery, which may result in loss of sphincter control.
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.