Breast—DCIS (Ductal Carcinoma In Situ)
Concept
Premalignant lesion with various subtypes. Pt has about a 1 in 3 chance of developing invasive ductal carcinoma in her lifetime. Several key features from pathologic stand- point: size of tumor, was it unifocal or multifocal, comedo necrosis, how well differentiated was the tumor?
Way Question May be Asked?
“51 y/o female presents to your office with an abnormal mammogram. A cluster of 5 microcalcifications were seen in the UOQ of the left breast. She underwent a core-nee- dle biopsy that revealed DCIS. What would you do?” May be given DCIS in a number of different ways from mam- mogram showing asymmetric density, nodule, speculated lesion, but most commonly from cluster or branching het- erogenous microcalcifications.
How to Answer?
History
Establish risk factors for breast cancer (menarche, breast- feeding, family history of breast/ovarian/ prostate can- cer, number of children, previous breast cancer, . . .)
Physical Exam
Symmetry, dimpling, erythema Try to palpate for any masses Check both breasts!
Examine for adenopathy
How to Answer?
Need to order bilateral mammograms and compare to previous
Ultrasound useful in palpable masses to determine if cystic or solid
MRI not used for screening purposes
Any suspicious microcalcifications (clustered, branch- ing, heterogeneous) need to be biopsied (stereotactic core needle or needle localization/excisional biopsy) After biopsy has identified lesion as DCIS, the pt still
needs that area excised with adequate (> 2 mm) free margins. If you don’t get this after your needle-loc, you’ll need to re-excise until you begin to distort the breast, or you get free margins
If DCIS is diffuse: multifocal (scattered in one quad- rant) or other quadrants (multicentric), consider total mastectomy
If the tumor is high grade, has comedo necrosis, or is large, a total mastectomy is appropriate (no ALND necessary here unless final path reveals invasive car- cinoma)—be sure to offer immediate reconstruction as an option
Pt will need post-op XRT (unless had mastectomy or has low grade, small tumor with > 1 cm margin) to breast and be placed on 5 years Tamoxifen (unless contraindication like endometrial CA or h/o DVTs)
Common Curveballs
There will be a palpable mass (separate from mammo- graphic finding)
There will be more than one mammographically detected lesion
There will be lesion in opposite breast
Pt will have recurrence after mastectomy to chest wall or incision site (changing scenario)
Pt will have invasive carcinoma (changing scenario) On pathology, resection margin will be positive or less
than 1 mm Pt will be pregnant
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6 Breast—Ductal Carcinoma In Situ
Stereotactic core can’t be performed (too superficial or too deep or pt can’t lay prone on stereotactic table) Lobular carcinoma in situ on final pathology (maybe
even at margins)
Strikeouts
Forgetting to examine both breasts
Forgetting to order bilateral mammograms
Forgetting post-op chemo/XRT treatment when appro- priate
Forgetting ALND if invasive cancer identified Performing ALND for DCIS
Talking about SLN Bx for comedo DCIS (only in research protocols currently)
Talking about use of chemotherapy/Arimidex/or the new med you read about in the journal last week as an experimental trial for your pt with DCIS
Not performing re-excision for margin < 1 mm.
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