Grade 2 lesions
In grade 2 lesions, which are soft tissue sarcomas not included in grade 1 and grade 3 lesions, less than 15% of the surface area shows necrosis, and there are fewer than five mitotic figures per ten high-power fields (40X objective). As secondary criteria of grade 2 tumors, the incidence of nuclear atypia is not marked, and the tumor is not markedly cellular.
Grade 3 lesions
- Alveolar soft part sarcoma.
- Clear cell sarcoma (MMSP).
- Desmoplastic small round cell tumor.
- Epithelioid sarcoma.
- Extraosseous osteosarcoma.
- Mesenchymal chondrosarcoma.
- Pleomorphic or round cell liposarcoma.
- Synovial sarcoma.
- Triton tumor (MPNST with rhabdomyosarcomatous elements).
- Undifferentiated soft tissue sarcoma.
Any other sarcoma not included in grade 1 in which more than 15% of the surface area is necrotic or in which there are more than five mitotic figures per ten high-power fields (40X objective) is considered a grade 3 lesion. Marked atypia and cellularity are less predictive but may assist in placing tumors in this category.
Although a standardized staging system for pediatric NRSTS does not exist, the current COG trial is using the sixth edition AJCC staging system for soft tissue sarcomas (with central pathology review).
Prognostic Significance of Tumor Staging
These two staging systems have proven to be of prognostic significance in pediatric and adult NRSTSs.[11,12,13,14,15] In a review of a large adult series of NRSTSs, superficial extremity sarcomas have a better prognosis than deep tumors. Thus, in addition to grade and size, the depth of invasion of the tumor should be considered.
Several adult and pediatric series have shown that patients with large or invasive tumors have a significantly worse prognosis than do those with small, noninvasive tumors. A retrospective review of soft tissue sarcomas in children and adolescents suggests that the 5 cm cutoff used for adults with soft tissue sarcoma may not be ideal for smaller children, especially infants. The review identified an interaction between tumor diameter and body surface area. This relationship requires further study to determine the therapeutic implications of the observation.
- Weiss SW, Goldblum JR: Enzinger and Weiss's Soft Tissue Tumors. 4th ed. St. Louis, Mo: Mosby, 2001.
- Maurer HM, Beltangady M, Gehan EA, et al.: The Intergroup Rhabdomyosarcoma Study-I. A final report. Cancer 61 (2): 209-20, 1988.
- Harmer MH, ed.: TNM Classification of Pediatric Tumors. Geneva: UICC, 1982.
- Soft tissue sarcoma. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 291-6.
- Parham DM, Webber BL, Jenkins JJ 3rd, et al.: Nonrhabdomyosarcomatous soft tissue sarcomas of childhood: formulation of a simplified system for grading. Mod Pathol 8 (7): 705-10, 1995.
- Recommendations for the reporting of soft tissue sarcomas. Association of Directors of Anatomic and Surgical Pathology. Mod Pathol 11 (12): 1257-61, 1998.
- Skytting B, Meis-Kindblom JM, Larsson O, et al.: Synovial sarcoma--identification of favorable and unfavorable histologic types: a Scandinavian sarcoma group study of 104 cases. Acta Orthop Scand 70 (6): 543-54, 1999.
- Coindre JM, Terrier P, Guillou L, et al.: Predictive value of grade for metastasis development in the main histologic types of adult soft tissue sarcomas: a study of 1240 patients from the French Federation of Cancer Centers Sarcoma Group. Cancer 91 (10): 1914-26, 2001.
- Dantonello TM, Int-Veen C, Leuschner I, et al.: Mesenchymal chondrosarcoma of soft tissues and bone in children, adolescents, and young adults: experiences of the CWS and COSS study groups. Cancer 112 (11): 2424-31, 2008.
- American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002.
- Rao BN: Nonrhabdomyosarcoma in children: prognostic factors influencing survival. Semin Surg Oncol 9 (6): 524-31, 1993 Nov-Dec.
- Pisters PW, Leung DH, Woodruff J, et al.: Analysis of prognostic factors in 1,041 patients with localized soft tissue sarcomas of the extremities. J Clin Oncol 14 (5): 1679-89, 1996.
- Coindre JM, Terrier P, Bui NB, et al.: Prognostic factors in adult patients with locally controlled soft tissue sarcoma. A study of 546 patients from the French Federation of Cancer Centers Sarcoma Group. J Clin Oncol 14 (3): 869-77, 1996.
- Pappo AS, Fontanesi J, Luo X, et al.: Synovial sarcoma in children and adolescents: the St Jude Children's Research Hospital experience. J Clin Oncol 12 (11): 2360-6, 1994.
- Pratt CB, Maurer HM, Gieser P, et al.: Treatment of unresectable or metastatic pediatric soft tissue sarcomas with surgery, irradiation, and chemotherapy: a Pediatric Oncology Group study. Med Pediatr Oncol 30 (4): 201-9, 1998.
- Brooks AD, Heslin MJ, Leung DH, et al.: Superficial extremity soft tissue sarcoma: an analysis of prognostic factors. Ann Surg Oncol 5 (1): 41-7, 1998 Jan-Feb.
- Ferrari A, Miceli R, Meazza C, et al.: Soft tissue sarcomas of childhood and adolescence: the prognostic role of tumor size in relation to patient body size. J Clin Oncol 27 (3): 371-6, 2009.