Investigations
1st investigations to order
mammography
Test
Mammography is recommended for screening and diagnosis.
A mammographic finding in one breast of clustered microcalcifications 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.
Lobular carcinoma in situ (LCIS) does not have classic mammographic findings.
If microcalcifications are not detected by mammography, then compression mammography or mammographic magnification views may be considered. Magnification views are also indicated in non-specific lesions.
National Comprehensive Cancer Network (NCCN) guidelines recommend digital breast tomosynthesis (three-dimensional mammography) alongside conventional two-dimensional mammography for screening and diagnosis, which may reduce the need for additional imaging.[47]
Mammographic sensitivity is lower in women with dense breasts, therefore supplemental imaging (e.g., ultrasound, MRI) may be warranted in these women.[47][48][49][50]
Result
calcifications suggest DCIS
Investigations to consider
core needle biopsy
Test
Comedo lesion and high nuclear grade indicate more aggressive ductal carcinoma in situ. Size of lesion, margin size, comedo, nuclear grade, and age are used to determine Van Nuys score.
Stereotactic core needle biopsy is the preferred method of biopsy if microcalcifications are present. 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.
Ultrasound-guided core needle biopsy is preferred if a non-palpable mass is found on laboratory. A handheld ultrasound is used to guide the biopsy needle and the biopsy carried out.
Result
necrosis and high nuclear grade
excisional biopsy
Test
Excisional biopsy is recommended if core needle biopsy cannot be performed, results are indeterminate, or benign and discordant with imaging.[47] Excisional biopsy is also recommended for non-classic lobular carcinoma in situ (LCIS; pleomorphic or florid).[47]
Excisional biopsy provides a complete diagnosis and the opportunity for treatment. However, it is associated with poorer cosmesis than needle biopsies, is more costly, and requires surgery.
Result
diagnostic
sentinel lymph node biopsy (SLNB)
Test
Should be strongly considered if the patient is undergoing mastectomy, or if tumour excision occurs in an anatomical location making it difficult to perform a future SLNB.[62] Guidelines do not recommend SLNB in women with DCIS who are undergoing breast-conserving surgery.[62][63]
Result
may show metastasis, indicating missed invasive carcinoma
breast magnetic resonance imaging (MRI)
Test
Considered if mammography shows no microcalcification
Mammographic sensitivity is lower in women with dense breasts, therefore supplemental MRI may be warranted in these women.[47][48][49][50]
MRI may be helpful in detecting high-grade ductal carcinoma in situ (DCIS).[51][52][53]
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.[54][55]
Breast MRI should not be used routinely for the preoperative work-up of patients with DCIS.[56][57][58]
Result
tissue enhancement, especially with high-grade DCIS
breast ultrasound
Test
Considered if mammography is non-specific, or shows no microcalcification, 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.[47][48][49][50]
Result
cystic versus solid lesion; shape of solid lesion
hormone receptor testing
Test
Oestrogen and progesterone receptor status is measured by immunohistochemical staining of fixed tumour tissue. Results can help to guide treatment.[64]
Result
positive or negative
genetic evaluation
Test
Genetic counselling and 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).[65][66][67][68][69]
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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