Pregnancy-Associated Breast Cancer

Section: Breast Curriculum:

Definition

• Diagnosis of Breast Cancer during pregnancy or within 1-year post-partum

Incidence

• 1% of all breast cancer
• Trimesters
  • 1st trimester = D1 > 12 weeks
  • 2nd = 13/40 to 27/40 (15 weeks)
  • 3rd = 28/40 to delivery (13+)
• Second most common cancer in pregnancy (Cervical = #1)

Clinical

• Often presents late because of all the changes that occur in breast during pregnancy
• Mostly palpable mass – often difficult to examine gravid breast

Pathology

• Same as normal though often ER/PR negative

Differential diagnosis

• Abscess, Galactocele, lobular hyperplasia, cystic disease, fibroadenoma, lactating adenoma, hamartoma

Investigations

• Triple assessment
  • Mammogram safe with abdo shield (detect 80-90% PABC)
  • USS – safe in pregnancy
  • Core biopsy – far better than FNA to get adequate result in gravid breast
    • Small risk of milk fistula
• Staging – CXR safe, try to avoid CT scan
  • MRI if required (with no gadolinium as can cross placenta)
  • Generally don’t do bone scan in pregnancy

Management – Stages of Pregnancy

• Treatment should not be delayed due to pregnancy
• Need to involve oncologist, surgeon and obstetrician
• There may be an increased risk of foetal loss with surgery in 1st trimester
• Anaesthetist/surgeon aware of physiological changes in pregnancy:
  • Increased coagulability
  • Decreased lung capacity
  • Increased risk of aspiration
  • Reduced uterus perfusion from prolonged supine position – tilt Left lateral
  • Increased circulated blood volume (Plasma > RBC) ~ Dilutional Anaemia > Decreased O2 carrying capacity
  • Increased CO + Reduced Systemic Resistance
  • Monitor foetus intra/post operatively

1st Trimester

• BCS generally contraindicated as radiotherapy would be delayed
• Chemo contraindicated - high risk of foetal demise/malformation
  • Risk of foetal malformation 20-25% (2nd and 3rd 1.3%)
  • Can delay chemo for up to 6/52 post surgery so may be able to get pts into 2nd trimester
• Local disease treatment with Mastectomy and ALND
• If advanced – consider termination for Chemo

2nd Trimester – Difficult

• BCS can be considered
  • RTx can be delayed by 4-6 months
  • And can delver a little early if needed, 35 weeks
• Can give neoadjuvent treatment
• Local disease treatment with Mastectomy and ALND
• Can give Chemo

3rd Trimester

• Normal surgical treatment + delayed adjuvant
• Risks mainly IUGR, prematurity, low BW
• Can consider BSC with RTx after delivery

Overview

	BCS	Chemotherapy	Endocrine	Trastuzaman	Treatment
First	No	No	No	No	Mastectomy + SLNB +/- ALND
Second	Yes (delay 4-6 months)	Yes	No	No	Normal options (apart from neo)
Third	Yes (delay after delivery)	Yes	No	No	Normal options (apart from neo)

Neoadjuvent chemotherapy (if indicated) stratified by receptor status (cannot give Herceptin or Endocrine treatment)

	ER/PR +ve HER -ve	HER +ve	Triple negative
First	No	No	No
Second	No	Maybe	Yes
Third	No	Maybe	Yes

Adjuvant Therapy

• Chemotherapy
  • Can be given in second and third trimester
  • Delay in giving chemo by 3 months = Increased risk of nodal mets by 5%
  • 5-FU and Doxorubicin thought to be safe
  • Taxanes unclear
• Trastuzumab
  • Avoid till after delivery
  • increased oligohydramnios which may lead to pulmonary hypoplasia, skeletal abnormalities, and neonatal death
• Endocrine therapy
  • Avoid till after delivery
  • Vaginal bleeding, miscarriage, congenital malformations, and fetal death

Locally advance cancer

• 3 Approaches for Locally Advanced Breast Cancer in Early Pregnancy:
  1. Termination and prompt oncological treatment
  2. Prompt oncological treatment with understanding of foetal risk
  3. Delay in treatment with understanding of oncological risk
• Women need to be aware chemotherapy may affect future fertility
• Also may advise to wait 2-5 years before 2nd pregnancy to avoid recurrence during pregnancy

Other considerations

• Safety of SLNB in pregnancy not established (controversial but increasing evidence showing safety)
  • Dyes probably should be avoided, radio-colloid probably okay
• NO Bone Scan, NO Tamoxifen, NO Herceptin
• Radiotherapy
  • Risk greatest before 25/40
  • Increased risk of childhood cancer by 40% (Absolute risk 3-4/1000)

Prognosis

• Usually more advanced at diagnosis
  • Median size 3.5 cm and 60% +ve LN
• Though probably not more aggressive cancers
• Biggest difference for locoregional recurrence is timing of treatment
  • If prompt treatment, then no difference from normal
• Overall worse prognosis for stage 3 disease for PABC cf non-PABC