Treatment Option Overview
Because of the rarity of pediatric nonrhabdomyosarcomatous soft tissue sarcomas (STSs), all children, adolescents, and young adults with these tumors should have their treatment coordinated by a multidisciplinary team comprising pediatric oncologists, pathologists, surgeons, and radiation oncologists. To better define the tumors' natural history and response to therapy, children with rare neoplasms should be considered for entry into national or institutional treatment protocols. Information about ongoing clinical trials is available from the NCI Web site.
Every attempt should be made to resect the primary tumor with negative margins before or after chemotherapy. Involvement of a surgeon with special expertise in the resection of STSs in the decision is highly desirable.
The timing of surgery depends on an assessment of the feasibility and morbidity of surgery. If the initial operation fails to achieve pathologically negative tissue margins or if the initial surgery was done without the knowledge that cancer was present, a re-excision of the affected area should be performed to obtain clear, but not necessarily wide, margins.[1-5] This surgical tenet is true even if no mass is detected by magnetic resonance imaging after initial surgery.; [Level of evidence: 3iiA]
Regional lymph node metastases at diagnosis are unusual and appear most likely with epithelioid and clear cell sarcomas. Sentinel lymph node mapping is employed at some centers to identify the regional nodes that are the most likely to be involved, although its widespread contribution to the staging and management of these tumors has yet to be clearly defined.[9-11]
Considerations for radiation therapy are based on the potential for surgery, with or without chemotherapy, to obtain local control without loss of critical organs, or significant functional, cosmetic or psychological impairment. This will vary according to patient variables, including age and gender, and tumor variables, including histopathology, site, size, and grade. Radiation therapy considerations include the same patient and tumor variables, surgical margin status, and expectations for radiation-induced morbidities such as impaired bone or muscle development, organ damage, or second malignancy. Radiation therapy can be given preoperatively or postoperatively, and the radiation field size and dose will again be based on patient and tumor variables and the operability of the tumor.
In general, radiation is indicated for patients with inadequate surgical margins and for larger, high-grade tumors.[12,13] This is particularly important in high-grade tumors with tumor margins smaller than 1 cm.[14,15]; [Level of evidence: 3iiDiv] With combined surgery and radiation therapy, local control of the primary tumor can be achieved in more than 80% of patients.[17,18] Preoperative radiation therapy has been associated with excellent local control rates.[19-21] This approach has the advantage of treating smaller tissue volumes because it does not necessitate treating a postsurgical bed; it also has the advantage of somewhat lower radiation doses because relative hypoxia from surgical disruption of vasculature and scarring is not present. Preoperative radiation therapy has been associated with an increased rate of wound complications in adults, primarily in lower extremity tumors, but the degree of this is questionable. Conversely, preoperative radiation therapy may lead to less fibrosis than with postoperative approaches, perhaps due to the smaller treatment volume and dose. Brachytherapy and intraoperative radiation may be applicable in select situations.[18,24,25]; [Level of evidence: 3iiiDii] In the recently closed COG-ARST0332 trial, preoperative radiation therapy was recommended for patients who presented with unresected tumor. The use of postoperative radiation therapy for patients who presented after primary resection was dependent on the tumor size, grade, and margin status.
Retroperitoneal sarcomas are a special issue since radiosensitivity of the bowel to injury makes postoperative radiation therapy less desirable. Reasons for this include the postoperative adhesions and bowel immobility that increase the risk of damage from any given radiation dose. This is in contrast to the preoperative approach in which the tumor often displaces bowel outside of the radiation field, and any exposed bowel is more mobile, which decreases exposure to specific bowel segments.
Radiation volume and dose depend on all patient, tumor, and surgical variables as noted above. Considerations include patient age and growth potential, the ability to avoid critical organs, epiphyseal plates, and lymphatics (but not the neurovascular bundles that are relatively radiation tolerant), and the functional/cosmetic outcome. Radiation margins are typically 2 cm to 4 cm longitudinally, and encompassing fascial planes axially. Radiation doses are typically 45 Gy to 50 Gy preoperatively, with consideration for postoperative boost of 10 Gy to 20 Gy if resection margins are microscopically or grossly positive, or planned brachytherapy if the resection is predicted to be subtotal. However, data documenting the efficacy of a postoperative boost are lacking. The postoperative radiation dose is 55 Gy to 60 Gy, or rarely, higher in the situation where unresectable gross residual disease exists.
The role of adjuvant (postoperative) chemotherapy remains controversial. A meta-analysis of updated data from adult STS patients from all available randomized trials concluded that recurrence-free survival was better with adjuvant chemotherapy for patients with high-grade tumors larger than 5 cm. The largest prospective pediatric trial failed to demonstrate any benefit with adjuvant vincristine, dactinomycin, cyclophosphamide, and doxorubicin. In a European trial, adults with completely resected STS were randomly assigned to observation or adjuvant chemotherapy with ifosfamide and doxorubicin. Adjuvant chemotherapy was not associated with improved event-free survival or overall survival. It is difficult to extrapolate this trial to pediatric patients because the trial included (1) a wide variety of histologies; (2) a relatively low dose of ifosfamide; (3) patients assigned to chemotherapy had definitive radiation delayed until completion of chemotherapy; and (4) almost one-half of the patients in the trial had intermediate-grade tumors. In the discussion section, the authors merged their patients with previously published series, including those from the European meta-analysis, and concluded that the results suggested a benefit for adjuvant chemotherapy.[Level of evidence: 1iiA]
Special Treatment Considerations for Children With STS
Many therapeutic strategies for children and adolescents with soft tissue tumors are similar to those for adult patients, although there are important differences. For example, the biology of the neoplasm in pediatric patients may differ dramatically from that of the adult lesion. Additionally, limb-sparing procedures are more difficult to perform in pediatric patients. The morbidity associated with radiation therapy, particularly in infants and young children, may be much greater than that observed in adults.
Improved outcomes with multimodality therapy in adults and children with STSs over the past 20 years has caused increasing concern about the potential long-term side effects of this therapy in children, especially when considering the expected longer life span of children versus adults. Therefore, to maximize tumor control and minimize long-term morbidity, treatment must be individualized for children and adolescents with nonrhabdomyosarcomatous STS. These patients should be enrolled in prospective studies that accurately assess any potential complications.
Treatment Options Under Clinical Evaluation
The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI Web site.
- ARST1321 (NCT02180867) (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery [PAZNTIS]): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation or chemotherapy (ifosfamide/etoposide) and radiation in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous STS. Subsequently, this trial will compare the rates of near complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation versus preoperative chemoradiation alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous STS; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous STS.
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- Sugiura H, Takahashi M, Katagiri H, et al.: Additional wide resection of malignant soft tissue tumors. Clin Orthop (394): 201-10, 2002. [PUBMED Abstract]
- Cecchetto G, Guglielmi M, Inserra A, et al.: Primary re-excision: the Italian experience in patients with localized soft-tissue sarcomas. Pediatr Surg Int 17 (7): 532-4, 2001. [PUBMED Abstract]
- Chui CH, Spunt SL, Liu T, et al.: Is reexcision in pediatric nonrhabdomyosarcoma soft tissue sarcoma necessary after an initial unplanned resection? J Pediatr Surg 37 (10): 1424-9, 2002. [PUBMED Abstract]
- Paulino AC, Ritchie J, Wen BC: The value of postoperative radiotherapy in childhood nonrhabdomyosarcoma soft tissue sarcoma. Pediatr Blood Cancer 43 (5): 587-93, 2004. [PUBMED Abstract]
- Kaste SC, Hill A, Conley L, et al.: Magnetic resonance imaging after incomplete resection of soft tissue sarcoma. Clin Orthop (397): 204-11, 2002. [PUBMED Abstract]
- Chandrasekar CR, Wafa H, Grimer RJ, et al.: The effect of an unplanned excision of a soft-tissue sarcoma on prognosis. J Bone Joint Surg Br 90 (2): 203-8, 2008. [PUBMED Abstract]
- Daigeler A, Kuhnen C, Moritz R, et al.: Lymph node metastases in soft tissue sarcomas: a single center analysis of 1,597 patients. Langenbecks Arch Surg 394 (2): 321-9, 2009. [PUBMED Abstract]
- Neville HL, Andrassy RJ, Lally KP, et al.: Lymphatic mapping with sentinel node biopsy in pediatric patients. J Pediatr Surg 35 (6): 961-4, 2000. [PUBMED Abstract]
- Neville HL, Raney RB, Andrassy RJ, et al.: Multidisciplinary management of pediatric soft-tissue sarcoma. Oncology (Huntingt) 14 (10): 1471-81; discussion 1482-6, 1489-90, 2000. [PUBMED Abstract]
- Kayton ML, Delgado R, Busam K, et al.: Experience with 31 sentinel lymph node biopsies for sarcomas and carcinomas in pediatric patients. Cancer 112 (9): 2052-9, 2008. [PUBMED Abstract]
- Marcus KC, Grier HE, Shamberger RC, et al.: Childhood soft tissue sarcoma: a 20-year experience. J Pediatr 131 (4): 603-7, 1997. [PUBMED Abstract]
- Delaney TF, Kepka L, Goldberg SI, et al.: Radiation therapy for control of soft-tissue sarcomas resected with positive margins. Int J Radiat Oncol Biol Phys 67 (5): 1460-9, 2007. [PUBMED Abstract]
- Blakely ML, Spurbeck WW, Pappo AS, et al.: The impact of margin of resection on outcome in pediatric nonrhabdomyosarcoma soft tissue sarcoma. J Pediatr Surg 34 (5): 672-5, 1999. [PUBMED Abstract]
- Skytting B: Synovial sarcoma. A Scandinavian Sarcoma Group project. Acta Orthop Scand Suppl 291: 1-28, 2000. [PUBMED Abstract]
- Hua C, Gray JM, Merchant TE, et al.: Treatment planning and delivery of external beam radiotherapy for pediatric sarcoma: the St. Jude Children's Research Hospital experience. Int J Radiat Oncol Biol Phys 70 (5): 1598-606, 2008. [PUBMED Abstract]
- Pratt CB, Pappo AS, Gieser P, et al.: Role of adjuvant chemotherapy in the treatment of surgically resected pediatric nonrhabdomyosarcomatous soft tissue sarcomas: A Pediatric Oncology Group Study. J Clin Oncol 17 (4): 1219, 1999. [PUBMED Abstract]
- Merchant TE, Parsh N, del Valle PL, et al.: Brachytherapy for pediatric soft-tissue sarcoma. Int J Radiat Oncol Biol Phys 46 (2): 427-32, 2000. [PUBMED Abstract]
- Sadoski C, Suit HD, Rosenberg A, et al.: Preoperative radiation, surgical margins, and local control of extremity sarcomas of soft tissues. J Surg Oncol 52 (4): 223-30, 1993. [PUBMED Abstract]
- Virkus WW, Mollabashy A, Reith JD, et al.: Preoperative radiotherapy in the treatment of soft tissue sarcomas. Clin Orthop (397): 177-89, 2002. [PUBMED Abstract]
- Zagars GK, Ballo MT, Pisters PW, et al.: Preoperative vs. postoperative radiation therapy for soft tissue sarcoma: a retrospective comparative evaluation of disease outcome. Int J Radiat Oncol Biol Phys 56 (2): 482-8, 2003. [PUBMED Abstract]
- O'Sullivan B, Davis AM, Turcotte R, et al.: Preoperative versus postoperative radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial. Lancet 359 (9325): 2235-41, 2002. [PUBMED Abstract]
- Davis AM, O'Sullivan B, Turcotte R, et al.: Late radiation morbidity following randomization to preoperative versus postoperative radiotherapy in extremity soft tissue sarcoma. Radiother Oncol 75 (1): 48-53, 2005. [PUBMED Abstract]
- Schomberg PJ, Gunderson LL, Moir CR, et al.: Intraoperative electron irradiation in the management of pediatric malignancies. Cancer 79 (11): 2251-6, 1997. [PUBMED Abstract]
- Nag S, Shasha D, Janjan N, et al.: The American Brachytherapy Society recommendations for brachytherapy of soft tissue sarcomas. Int J Radiat Oncol Biol Phys 49 (4): 1033-43, 2001. [PUBMED Abstract]
- Viani GA, Novaes PE, Jacinto AA, et al.: High-dose-rate brachytherapy for soft tissue sarcoma in children: a single institution experience. Radiat Oncol 3: 9, 2008. [PUBMED Abstract]
- Al Yami A, Griffin AM, Ferguson PC, et al.: Positive surgical margins in soft tissue sarcoma treated with preoperative radiation: is a postoperative boost necessary? Int J Radiat Oncol Biol Phys 77 (4): 1191-7, 2010. [PUBMED Abstract]
- Ferrari A: Role of chemotherapy in pediatric nonrhabdomyosarcoma soft-tissue sarcomas. Expert Rev Anticancer Ther 8 (6): 929-38, 2008. [PUBMED Abstract]
- Adjuvant chemotherapy for localised resectable soft-tissue sarcoma of adults: meta-analysis of individual data. Sarcoma Meta-analysis Collaboration. Lancet 350 (9092): 1647-54, 1997. [PUBMED Abstract]
- Woll PJ, Reichardt P, Le Cesne A, et al.: Adjuvant chemotherapy with doxorubicin, ifosfamide, and lenograstim for resected soft-tissue sarcoma (EORTC 62931): a multicentre randomised controlled trial. Lancet Oncol 13 (10): 1045-54, 2012. [PUBMED Abstract]
- Suit H, Spiro I: Radiation as a therapeutic modality in sarcomas of the soft tissue. Hematol Oncol Clin North Am 9 (4): 733-46, 1995. [PUBMED Abstract]
- Okcu MF, Pappo AS, Hicks J, et al.: The nonrhabdomyosarcoma soft tissue sarcomas. In: Pizzo PA, Poplack DG, eds.: Principles and Practice of Pediatric Oncology. 6th ed. Philadelphia, Pa: Lippincott Williams and Wilkins, 2011, pp 954-86.