13.4 Grade: The Four Time-Specific Grade Items & Site-Specific Grade Tables

Why grade has four items

Treatment can change a tumor's grade, and AJCC stages cancers in separate time frames. For cases diagnosed in 2018 and later, the Grade Manual replaced the old single Grade item [440] and the Collaborative Stage grade-related site-specific factors with time-specific items:

General rules for solid tumors

1. Primary tumor only. Do not code grade from a metastasis or recurrence. The rare exception is contiguous extension when primary tissue is unavailable. If the primary site is unknown, grade is 9.
2. Ranges: for "grade 2–3," code the higher grade.
3. More than one grade in the same time frame: the AJCC-recommended system has priority. Within it, code the highest grade.
4. In situ and invasive: code a grade given for an in situ tumor, but never code dysplasia (for example, "high-grade dysplasia") as grade. If both in situ and invasive parts exist, code only the invasive grade, even if it is unknown.
5. Priority of sources: the synoptic report (including the CAP protocol), then the final diagnosis, then a physician statement.
6. Clinical grade before neoadjuvant therapy: code Grade Clinical from information before neoadjuvant therapy, even if it is unknown.
7. Consults: if outside slides are reviewed and the grade differs, record the consult grade. A facility re-read with an updated report also counts as a consult.
8. Only one grade, time frame unclear: code it as Grade Clinical, set Grade Pathological to 9, and leave both post-therapy items blank.

When Grade Pathological uses the clinical grade

Grade Pathological can include the clinical workup grade, because pathological staging uses all information from diagnosis through resection. Use the clinical grade when:

• the clinical and pathological behavior are the same and the clinical grade is the highest;
• the clinical diagnosis was invasive but the resection showed only in situ;
• the resection documents no grade, or there is no residual cancer;
• there was no resection, but distant metastasis was microscopically confirmed during the clinical time frame.

When Grade Pathological is 9

• Grade was not documented, and no clinical grade is available.
• There was no resection of the primary, except the metastasis case above.
• Neoadjuvant therapy was followed by resection. The resection grade goes to yp.
• It is a clinical case only, or "not applicable" was checked on the CAP protocol with no other grade.

Preferred system mismatch: the Grade Manual example is a biopsy showing a moderately differentiated adenocarcinoma, coded G2 in a table whose preferred system is differentiation, and a resection that says only "high grade," a term that table does not accept. Grade Clinical is 2 and Grade Pathological is 9; the clinical G2 is not copied into the pathological item.

Code structure

When AJCC needs grade for a stage group, codes A–D count as unknown grade, which can make the stage group unknown.

High-yield site tables

Breast (Grade ID 12)

• Invasive: Nottingham (Scarff-Bloom-Richardson) combined histologic grade. Tubule formation, nuclear pleomorphism and mitotic count are each scored 1–3: a total of 3–5 = G1, 6–7 = G2, 8–9 = G3. "Grade 2" with no other detail is assumed to be Nottingham grade.
• If only "well/moderately/poorly differentiated" is stated for an invasive tumor, use A–D. Do not use L, M or H for invasive tumors.
• In situ (DCIS): nuclear grade L, M, H. Notation such as "2/3" is nuclear grade. Do not use 1–3 for in situ tumors.
• Nodes only (T0): grade from nodal tissue may be used only when no primary tumor was ever found.
• Example: a biopsy shows DCIS, nuclear grade 3, and the lumpectomy shows invasive carcinoma with Nottingham score 7. Grade Clinical is H, Grade Pathological is 2, and the behavior is /3.

Prostate (Grade ID 17)

Codes 1–5 take priority over A–E. A TURP or simple prostatectomy gives a clinical grade only.

Other examples

• Endometrioid endometrial carcinoma: FIGO grade 1–3. The Grade Manual maps "low grade" to FIGO 2 and "high grade" to FIGO 3.
• Urothelial (bladder): L (low grade) and H (high grade).
• Many GI and head and neck sites: G1–G4 (well to undifferentiated).

Hematopoietic and lymphoid neoplasms

For histologies 9590–9993, Grade Clinical and Grade Pathological are coded 8 (not applicable), and the post-therapy items are blank. The old cell-lineage indicator (B-cell, T-cell, null, NK) that used to go in Grade is no longer collected for 2018 and later cases. The exception is lymphoma of the ocular adnexa: follicular lymphoma histologies (9690, 9691, 9695, 9698) at C441, C690, C695 and C696 are graded under the AJCC ocular adnexa system.

Derived Summary Grade 2018 [1975]

Central registries derive this item from Grade Clinical and Grade Pathological, not the post-therapy items, to compare grade with pre-2018 data. Hospital registrars do not code it.