Editing DCIS (section)

== Other treatment considerations ==

* Margins
** Controversial
** >2mm is often considered adequate to declare negative margin - does not significantly increase recurrence rate compared to bigger margins
** <2mm should be considered for re-excision, although >1mm is acceptable in the UK
* SLNB
** Not typically performed with DCIS unless doing a mastectomy
** Indications
*** Microinvasion on core biopsy
*** Otherwise concerning for invasive disease
*** Mastectomy for DCIS (since won't be able to do it later if it's upstaged to invasive on pathology specimen)
*** High-grade, large (>5cm) or palpable DCIS (since there may be a subsequent upstaging based on pathological specimen, which happens about 15% of the time in this cohort)
* Hormone therapy
** If DCIS is ER/PR positive, can give adjuvant hormone therapy for 5 years (either anastrazole or tamoxifen are ok) 
** Benefit only seen with ER-positive DCIS
** Especially important in high-risk patients
** Probably not necessary after mastectomy
** Improves local control after breast-conserving therapy and prevents new tumours
** After 7 years, reduced ipsilateral breast cancer from 9% to 6% and reduced the risk of new contralateral breast cancer by 47%
* Chemotherapy
** Not indicated, as the rate of metastatic disease is so low