Soft tissue
Staging
General

Senior Author: Michael R. Clay, M.D.
Editor-in-Chief: Debra Zynger, M.D.

Topic Completed: 1 November 2018

Revised: 19 March 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Staging[TI] soft tissue[TI]
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Cite this page: Malik F, Clay MR. Staging - general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuestaging.html. Accessed March 19th, 2019.

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:
    1. Extremity and trunk
    2. Retroperitoneum
    3. Head and neck
    4. Visceral 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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