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Adult Soft Tissue Sarcoma Treatment (PDQ®)

Health Professional Version
Last Modified: 02/28/2014

Stage Information for Adult Soft Tissue Sarcoma

Definitions of TNM and Grade

Staging has an important role in determining the most effective treatment for soft tissue sarcoma. Clinical staging involves magnetic resonance imaging (MRI) or computed tomography (CT) of the primary tumor area and a chest CT to look for metastasis to the lung (the most common site of distant spread). An abdominal CT scan is done in the case of retroperitoneal sarcomas because the liver may be the site of initial clinical metastasis for these tumors.

The stage is determined by the size of the tumor, the histologic grade, and whether there is spread to lymph nodes or distant sites. Intracompartmental or extracompartmental extension of extremity sarcomas is also important for surgical decision making. For complete staging, a thorough review of all biopsy specimens (including those from the primary tumor, lymph nodes, or other suspicious lesions) is essential. CT scan of the chest is recommended for sarcomas larger than 5 cm (T2) or with moderate to poor differentiation (grades 2–4). Nodal involvement is rare, occurring in less than 3% of patients with sarcoma.[1]

Lymph node involvement in soft tissue sarcomas of adulthood is rare but is somewhat more frequent in some subtypes (e.g., rhabdomyosarcoma, vascular sarcomas, clear cell sarcomas, and epithelioid sarcomas) when they are high grade.[2] Because treatment decisions are predicated on pathology staging, patients should be staged before, and again after, any neoadjuvant therapy. The assessment of tumor grade can be affected in either direction, but more frequently decreased because of differential cellular loss related to the neoadjuvant chemotherapy or radiation.[3] Grade, which is based on cellular differentiation, mitotic rate, and extent of necrosis, should be recorded for all soft tissue sarcomas. A three-grade system (G1–G3) is preferred. (See Table 4 below).

The American Joint Committee on Cancer (AJCC) has designated staging by the four criteria of tumor size, nodal status, metastasis, and grade (TNMG).[3] The characteristic molecular markers of some sarcomas are not formally incorporated in the staging system pending further evaluation of their impact on prognosis. Recurrent sarcomas are restaged using the same system as for primary tumors with the specification that the tumor is recurrent.

Definitions of TNM and Grade

Table 1. Primary Tumor (T)a,b
TXPrimary tumor cannot be assessed.
T0No evidence of primary tumor.
T1Tumor ≤5 cm in greatest dimension. (Size should be regarded as a continuous variable, and the measurement should be provided.)
T1aSuperficial tumor.b
T1bDeep tumor.b
T2Tumor >5 cm in greatest dimension.b
T2aSuperficial tumor.b
T2bDeep tumor.

aReprinted with permission from AJCC: 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 291-8.
bSuperficial tumor is located exclusively above the superficial fascia without invasion of the fascia; deep tumor is located either exclusively beneath the superficial fascia, superficial to the fascia with invasion of or through the fascia, or both superficial yet beneath the fascia.

Table 2. Regional Lymph Nodes (N)a
NXRegional lymph nodes cannot be assessed.
N0No regional lymph node metastasis.
N1bRegional lymph node metastasis.

aReprinted with permission from AJCC: 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 291-8.
bPresence of positive nodes (N1) in M0 tumors is considered Stage III.

Table 3. Distant Metastasis (M)a
aReprinted with permission from AJCC: 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 291-8.
M0No distant metastasis.
M1Distant metastasis.

Table 4. Anatomic Stage/Prognostic Groupsa
aReprinted with permission from AJCC: 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 291-8.
Stage IAT1aN0M0G1, GX
T1bN0M0G1, GX
Stage IBT2aN0M0G1, GX
T2bN0M0G1, GX
Stage IIAT1aN0M0G2, G3
T1bN0M0G2, G3
Stage IIBT2aN0M0G2
T2bN0M0G2
Stage IIIT2a, T2bN0M0G3
Any TN1M0Any G
Stage IVAny TAny NM1Any G

Neurovascular and bone invasion are indicators of poor prognosis, but they are not incorporated into the formal staging system.

References
  1. Fong Y, Coit DG, Woodruff JM, et al.: Lymph node metastasis from soft tissue sarcoma in adults. Analysis of data from a prospective database of 1772 sarcoma patients. Ann Surg 217 (1): 72-7, 1993.  [PUBMED Abstract]

  2. Mazeron JJ, Suit HD: Lymph nodes as sites of metastases from sarcomas of soft tissue. Cancer 60 (8): 1800-8, 1987.  [PUBMED Abstract]

  3. 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.