Recommendation Grading
Type Benefit/harm Evidence Quality
Strength of
Recommendation
EB Evidence-based B Benefits
outweigh
harms
H High Strong
CB/
FC
Consensus-
based/Formal
Consensus
H Harms
outweigh
benefits
I Intermediate Moderate
IC Informal
consensus
B/H Relative
balance of
benefits
and harms
L Low Weak
N No
recommendation
U Benefits/
harms
ratio
uncertain
Ins Insufficient
Key Points
➤ This update expands the scope of the 2015 guideline to address topics that
have emerged since its publication:
• Testing for PIK3CA and estrogen receptor 1 gene (ESR1) somatic variants and
germline BReast CAncer gene 1 (BRCA1), BReast CAncer gene 2 (BRCA2), and
partner and localizer of BRCA2 (PALB2) pathogenic variants (mutations) to guide
therapy.
• Testing tumors for homologous recombination deficiency, expression of programmed
cell death ligand-1 (PD-L1), deficient mismatch repair microsatellite instability
(dMMR/MSI), tumor mutational burden (TMB), neurotrophic tyrosine receptor
kinase (NTRK) gene fusions, and trophoblast cell-surface antigen 2 (TROP2)
expression to determine eligibility for selected treatments.
• The use of cell-free, circulating tumor DNA (ctDNA) and circulating tumor cells
(CTCs) for monitoring treatment response.
