Soft tissue
General
Staging-general
Authors: Faizan Malik, M.B.B.S., Michael R. Clay, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Topic Completed: 1 November 2018
Minor changes: 16 November 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Staging[TI] soft tissue[TI]
Cite this page: Malik F, Clay MR. Staging-general. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissuestaging.html. Accessed April 18th, 2021.
Pathologic TNM staging of soft tissue, AJCC 8th edition
Definition / general
- Significant changes are made in the 8th edition of the AJCC cancer staging manual for soft tissue sarcomas; there is an emphasis on primary anatomic site, due to variability in clinical implications
- This edition divides sarcomas into 4 anatomic sites:
- Staging system applies to soft tissue sarcomas but excludes fibromatosis (desmoid tumor) and Kaposi sarcoma
- Other exclusions vary according to the different anatomic sites mentioned above (Amin: AJCC Cancer Staging Manual, 8th Edition, 2018)
- Other exclusions are also mentioned under relevant topics
- Histologic grading according to French Federation of Cancer Centers Sarcoma Group (FNCLCC) grading system is done in all sarcomas except GIST (see below for details)
Rules for classification
- Tumor (T):
- Based on the tumor size, as measured grossly or with imaging
- Largest dimension in any plane
- Best to provide 3 dimensional size if possible
- Nodes (N):
- N status needs to be determined both clinically and microscopically
- If clinically negative, use cN0, if microscopically determined, use pN0
- If there was no evidence of nodal disease either upon clinical examination or with imaging studies, use cN0, not pNX
- Metastasis (M):
- Either localized (M0) or metastatic (M1)
- Grade (G):
- Should be assigned to all sarcomas and follows the French Federation of Cancer Centers Sarcoma Group System (FNCLCC)
- Scores are generated based on 3 variables: differentiation (based on tumor type and histology), mitotic rate and necrosis
- See AJCC staging manual for a complete list of differentiation scores and scoring criteria
- Prefix:
- If the lesion was previously treated, use the prefix y (yTNM), if the lesion is recurrent, use r (rTNM)
Notes:
- Depth:
- Depth is no longer used in the updated staging system
- Depth had little impact on outcome and was inapplicable in various locations
- Core biopsies:
- Grading in core biopsies can be difficult
- If multiple cores show a high grade neoplasm, the tumor may be designated as such, as the likelihood of downgrading is remote
- Caution should be emphasized in lower grade lesions, however, as limited sampling at the time of core biopsy may result in upgrading in the final tumor
- Molecular testing:
- Although a wide range of molecular and genetic determinants of sarcomas are currently being used worldwide, it has not yet been incorporated in the 8th edition of AJCC for staging purposes
- Complexity INdex in SARComas (CINSARC):
- Recently described tool that outperforms histologic grading in determining prognosis (Sci Rep 2017;7:5480)
- Based on gene expression signatures
- May one day augment risk assessment
- Prospective trials are ongoing
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