Breast Flashcards
HER2 positivity
HER2+ IHC is graded 1+ to 3+ (1+ = weak; 3+ = strong)
HER2 IHC 1+ = negative
HER2 IHC 2+ = equivocal, requires confirmatory FISH
HER2 IHC 3+ = positive
FISH Tests: HER2/CEP17 and HER2 CN
HER2/CEP17 > 2 = Positive
HER2/CEP17 = HER2 gene/chromosome 17 centromere expression
HER2 CN >6 = Positive
HER2 CN = HER2 copy number
Side effects of CDK inhibitors
Palbociclib - neutropenia
Ribociclib - QTC, LFTs
Abemacicib - diarrhea; better cns penetration
Oncotype interpretation
< 16 = no chemotherapy required (score 0-15 tamoxifen fine; >15, consider tam
+ OS)
16-25 = consider chemotherapy in pre-menopausal women (based on TailorX trial were premenopausal women benefited from chemo however was this more related to OS from chemo)
>21 = benefit to chemotherapy in pre-menopausal women
>26 = benefit to chemotherapy in post-menopausal (based on Rxponder data where post-menopausal women even with 1-3 LNs+ didn’t mention unless score <26)
SERM versus SERD
SERM = different from typical agonist or antagonist because action is different in various tissues, thereby granting the possibility to selectively inhibit or stimulate estrogen-like action in various tissue
versus
SERD = causes the ER to be degraded and thus downregulated (Fulvestrant) → ER antagonist without agonist activity
HER2+ BC Adjuvant Therapy Approach
<5mm: Surgery
5mm-2cm: Surgery + Adjuvant TCH
> 2cm or N+: NAT with TCHP + Surgery → TD-M1 if residual disease (neratinib after antibodies also approved and could be considered if high risk dx)
When to use RT in localized BC
RT = used always w/ lumpectomy (3-5 weeks)
Used sometimes w/ mastectomy (>5cm, T4 dx, LN usually 4+ LN, +margins, consider extensive LVI)
Adjuvant treatment for male ER+ breast cancer
Tamoxfen is SOC; if AI given, need to give with LHRH analog (lupron) to shut down pituitary gland; could do AI/lupron/palbo as 2nd line
