RCPA Protocols Flashcards
Breast T staging
based on largest tumour (invasive component only):
- size (2 and 5 cm cutoffs for T2, T3)
- extension to chest wall (not just muscle) or skin ulceration (T4)
NB: tumours are separate if 5mm or more between
Breast N staging
i for isolated tumour cells (<0.2mm or <200 cells)
mol +/- for molecularly detected mets
mi for micromets (0.2 - 2mm)
cutoffs 4 (N2) and 10 (N3)
clinically detected nodes affect N stage
Breast - margins for which lesions?
invasive ca
DCIS
comedo- or pleomorphic LCIS
Breast - ancillary tests
ER: % nuclei and predominant intensity (>1 is +)
PR: % nuclei and predominant intensity (>1 is +)
HER2 ISH: copies >6 or ratio >2.2 (use FISH if ISH not definitive)
HER2 IHC: 0-3+
Breast - biomarker issues
can be on core or excision, but should repeat if negative
HER2 best on excision due to heterogeneity
prompt and adequate fixation (8-24 hrs) required
fix for at least 6-8 hours, even if a core!
use antigen retrieval, and internal and external controls
Breast - describe grading
nuclear grade: size, shape and chromatin
tubular differentiation: cutoffs 10% and 75%
mitotic count: use tables, based on field diameter (on mine: score 2 is 9-17/10HPF)
Breast - grading DCIS
use NHS BSP system:
low (monomorphic, 1-2x RBC)
intermediate (2-3x RBC)
high (pleomorphic, 3 xRBC, necrosis)
CRC - grading mesorectal completeness
incomplete (grade 1): defects down to muscularis
nearly complete (grade 2): irregular, clefts over 5mm
complete (grade 3): smooth, no coning, clefts under 5mm
CRC - grading
low or high
WHO: based on highest grade present, not including leading front of tumour
not graded: medullary, mucinous (low if MSI-H)
CRC - T stage
level of invasion
nb: T4a is serosa (use EVG if unsure) or perforation, T4b is adjacent structure
nb: serosal deposits are M1, therefore important to see continuity with tumour
CRC - which margins to measure?
end margins and circumferential margin
nb: +ve if <1mm (except for R status - needs to be at ink)
nb: margin is to tumour OR involved LN OR tumour deposit OR LVI
CRC - response to neoadjuvant therapy
complete response (G0): no viable tumour cells
moderate response (G1): single or small groups
minimal response (G2): tumour outgrown by fibrosis
poor response (G3): minimal or no tumour kill
nb: post therapy, acellular mucin pools and mucin in lymph nodes are considered negative for tumour
CRC - histologic features of MMR deficiency
TILs
medullary subtype
mucinous or signet ring subtype
CRC - routine ancillary tests
MMR IHC
if loss of MLH1: do BRAF (if positive, assume sporadic hypermethylation of MLH1)
Also RAS testing if requested, for metastatic disease (predicts response to anti-EGFR therapy)
CRC - R codes
R0: complete resection (margins/nodes negative)
R1: microscopic tumour only remains (at margin CAP, <1mm from margin RCP)
R2: macroscopic margin involved or gross disease
