DCIS Flashcards
Definition of DCIS
Proliferation of malignant epithelial cells in the ductal system with no evidence of invasion to surrounding stromal cells
Subtypes of DCIS
- Non-comedo:
- Comedo:
- Micropapillary
- Papillary
- Cribiform
- Solid
What is whole breast radiotherapy and what is the regimen?
1.8-2Gy per day for 5 weeks (total 50Gy)
Within 8 weeks of surgery
Risks of concomitant IDC in confirmed DCIS
10-20%
Risk of recurrent DCIS or IDC in 5 years
6.8%
Long term risk of contralateral IDC/DCIS in confirmed DCIS
3-10%
Evidence for RT after BCS in DCIS
- B17
- E5194 (ECOG)
- EORTC
Reduced local recurrence in IPSILATERAL BREAST
No difference in overall survival
Definition of low risk DCIS
- Low/ intermediate grade
- Smaller than 2.5 cm
- Widely negative margins (>1cm)
Evidence for omission of RT in low-grade DCIS
- E5194
- Radiation therapy oncology group 9804
Indications for mastectomy in DCIS
- >4cm tumor
- Multicentric tumor
- Contraindication for RT
- Male
- Persistent positive margin after BCS
Any evidence for surveillance in low grade DCIS
Ongoing LORIS trial
Would you offer SLNB in patient with DCIS
- Not done routinely except micro-invasion or invasive focus found after BCS
- Always perform SLNB if
- Undergoing mastectomy
- Mass forming DCIS
- > 4cm calcification and undergoing BCS (20-40% occult invasion)
- Documented microinvasion in core biopsy
How much does radiotherapy reduce risk of local recurrence in DCIS
3.9% absolute risk reduction
What are risk factors of recurrence for DCIS?
- Age >40
- Mass forming DCIS
- intermediate/ high grade
- cribiform/solid growth
- Indeterminant margins
Counseling for BCS in DCIS
- Risk of positive margin
- Defect in breast shape
- Detection of IDC may require subsequent SLNB
- Long term recurrence (~10%)
- Risk of not treating
- Risk of contralateral cancer
