Investigations
1st investigations to order
mammography
Test
At routine mammographic screening (which may comprise digital breast tomosynthesis [three-dimensional mammography] alongside conventional two-dimensional mammography), a finding of clustered microcalcifications in one breast, and absence of a soft-tissue abnormality, indicates ductal carcinoma in situ (DCIS). Calcifications may be linear, branching, or bizarre in comedo DCIS. Non-comedo DCIS may not be calcified or may present as fine granular powdery calcifications.
Mammographic magnification views may be employed to evaluate and count microcalcifications.
Lobular carcinoma in situ (LCIS) does not have classic mammographic findings.
Mammographic sensitivity is lower in women with dense breasts; therefore, supplemental imaging (e.g., ultrasound, MRI) may be warranted in these women.[53][73][74][75]
Result
calcifications suggest DCIS
Investigations to consider
core needle biopsy
Test
Core needle biopsy should be performed if a suspicious breast lesion is identified on imaging. Results are diagnostic, but may underestimate the extent of disease.[88][89]
Stereotactic (mammographically guided) core needle biopsy is the diagnostic procedure of choice in the setting of microcalcifications; it is nearly as accurate as excisional biopsy, with fewer complications.[90] Core needle biopsy may, however, underestimate the extent of disease.[91][92]
Performed with a patient prone on a metal table through which the breast descends. The lesion is then localised in two planes and the biopsy carried out.
Comedo lesion and high nuclear grade indicate more aggressive ductal carcinoma in situ (DCIS).
Architecturally, papillomas can cause false-positives. Furthermore, many breast malignancies contain elements of both in situ and invasive carcinoma. As such, a core needle biopsy demonstrating one component does not exclude the other.
Ultrasound-guided core needle biopsy is preferred if a non-palpable mass is found on imaging.
Result
diagnostic; necrosis and high nuclear grade
excisional biopsy
Test
Excisional biopsy is recommended: if core needle biopsy cannot be performed; when core needle biopsy results are indeterminate, or benign and discordant with imaging; if there is atypical ductal hyperplasia (ADH); for non-classic lobular carcinoma in situ (LCIS; pleomorphic or florid); for select patients (e.g., with classic LCIS, atypical lobular hyperplasia, flat epithelial atypia, papillomas without atypia, fibroepithelial lesions favouring fibroadenoma), depending on level of suspicion.[53]
Excisional biopsy provides a complete diagnosis and the opportunity for treatment. However, it requires surgery and is associated with poorer cosmesis than needle biopsy.
Size of lesion, margin size, comedo, nuclear grade, and age are used to determine the Van Nuys score for prognostic classification of ductal carcinoma in situ (DCIS). See Criteria.
Result
diagnostic
sentinel lymph node biopsy (SLNB)
Test
SLNB may be considered in the setting of: mastectomy for ductal carcinoma in situ (DCIS); excision in an anatomical location compromising the performance of a future SLNB procedure; or oncoplastic breast-conserving surgery.[66]
SLNB should not be routinely performed in women with preoperative (biopsy-determined) pure DCIS who are undergoing breast-conserving surgery, but it may be considered if there is high suspicion for invasive disease or axillary metastasis (e.g., palpable mass, extensive microcalcifications).[66][95][96]
Result
may show metastasis, indicating missed invasive carcinoma
breast magnetic resonance imaging (MRI)
Test
Mammographic sensitivity is lower in women with dense breasts, therefore supplemental MRI may be warranted in these women.[53][73][74][75]
MRI may be helpful in detecting high-grade ductal carcinoma in situ (DCIS).[76][77][78]
Although MRI can accurately detect additional lesions and contralateral cancer not identified using conventional imaging in primary breast cancer, MRI findings should be pathologically verified because of the high false-positive rate.[79][80]
Breast MRI is not routinely recommended for diagnostic evaluation because of the risk of false positives and potential for over-treatment.[81][82] Breast MRI should not be used routinely for the preoperative work-up of patients with DCIS.[83][84][85][66]
Result
tissue enhancement, especially with high-grade DCIS
breast ultrasound
Test
Considered if mammography is non-specific, or to differentiate solid from cystic lesions. For solid lesions, a taller-than-wide shape is more suspicious than wider-than-tall.
Mammographic sensitivity is lower in women with dense breasts, therefore supplemental ultrasound may be warranted in these women.[53][73][74][75]
Result
cystic versus solid lesion; shape of solid lesion
hormone receptor testing
genetic evaluation
Test
Genetic counselling and germline testing for high-penetrance breast cancer susceptibility genes (e.g., BRCA1, BRCA2, CDH1, PALB2, PTEN, STK11, and TP53) should be considered for women at high risk for hereditary breast cancer (e.g., based on personal and/or family history).[66][63][98][65][99][100]
Genetic testing for a specific pathogenic variant can be carried out, if known; germline multigene panel testing is recommended if the pathogenic variant is unknown or if personal and/or family history suggests involvement of more than one pathogenic variant.[63][101] Selection of the specific multigene panel should take into account the patient's personal and family history. Results can inform prognosis and may highlight risk among family members.
For specific criteria for genetic counseling and testing, see Primary invasive breast cancer.
Result
may be positive for BRCA1, BRCA2, CDH1, PALB2, PTEN, STK11, TP53
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