Colon Cancer Synoptic Report — CAP elements with AJCC staging guidance & Stage Group summary
Case / Specimen
Primary Tumor / Pathologic Findings
pT summary (concise):
pTis = carcinoma confined to mucosa (no invasion); pT1 = invades submucosa; pT2 = invades muscularis propria; pT3 = through muscularis propria into pericolorectal tissues; pT4a = penetrates visceral peritoneum; pT4b = invades/adheres to other organs/structures. Use yp prefix for post‑treatment.
Lymph Nodes
pN summary (concise):
pN0 = no regional nodal metastasis; pN0(i+) = ITCs only (<0.2 mm); pN1mi = micrometastasis (0.2–2.0 mm); pN1 = metastasis in 1–3 regional nodes (or N1c for tumor deposits when nodes negative); pN2 = metastasis in ≥4 regional nodes. Check edition details for numeric cutoffs/subcategories.
Biomarkers & Molecular
Note: MMR/MSI status affects prognosis and treatment (immunotherapy eligibility). Record method (IHC vs PCR/NGS) when available.
AJCC Stage Group Summary (concise tables & guidance)
Below are concise stage group summaries intended as guidance. Use the official AJCC manual (current edition) for authoritative, edition‑specific stage group tables and all nuances (prognostic stage adjustments, tumor deposits, ENE rules, yp staging, and subcategories).
Show/hide: Simplified Stage Group Table (high‑level)
Stage Group
Typical pT / pN / pM
Notes
0
pTis, N0, M0
Carcinoma in situ (intramucosal)
I
pT1–2, N0, M0
Tumor limited to bowel wall (submucosa/muscularis)
IIA
pT3, N0, M0
Through muscularis into pericolorectal tissues
IIB
pT4a, N0, M0
Penetrates visceral peritoneum
IIC
pT4b, N0, M0
Direct invasion of other organs/structures
III
Any T, N1–2, M0
Regional lymph node metastasis (substages depend on T and number of nodes)
IV
Any T, any N, M1
Distant metastasis present
Show/hide: Example detailed Stage Group breakdown (common categories)
Stage Group
Representative pT/pN combinations
IA
pT1, pN0
IB
pT2, pN0
IIA
pT3, pN0
IIB
pT4a, pN0
IIC
pT4b, pN0
IIIA
pT1–2, pN1 (1–3 nodes) — or select combinations depending on edition
IIIB
pT3–4a, pN1 — or selected T with 1–3 nodes
IIIC
Any T, pN2 (≥4 nodes) — or higher nodal burden
IV
Any T, any N, pM1
These representative combinations are simplified. Substage assignment (e.g., IIIA/IIIB/IIIC) depends on precise T and numeric N categories and differs by AJCC edition — consult the AJCC staging tables for exact mapping.
Staging Guidance (practical points)
Assign pT based on the deepest layer of invasion (see pT summary above).
Assign pN based on count and size (macro vs micrometastasis vs ITC) of regional nodes. Record tumor deposits (N1c) when nodes are negative but deposits present.
Combine pT/pN/pM to determine stage group using AJCC tables for the selected edition; yp prefix for post‑neoadjuvant staging.
Record extranodal extension (ENE) and follow edition‑specific rules whether ENE modifies pN or staging.
For prognostic staging (if used), AJCC may incorporate biomarkers/grade — consult manual.
Always verify final stage group against the official AJCC tables (copyrighted reference).