Sentinel lymph node biopsy for DCIS: are we approaching consensus?

Sentinel lymph node biopsy in low risk settings

BACKGROUND

Sentinel lymph node biopsy (SLNB) should be performed in patients with ductal carcinoma in situ (DCIS) undergoing mastectomy. Yet, the same logic is controversial in the setting of prophylactic mastectomy.

METHODS

Surgeons were surveyed as to their practices. Statistical analyses were performed to identify associated factors.

RESULTS

238 surgeons responded to the survey. 73.1% of respondents stated they would always perform SLNB in the setting of mastectomy for DCIS, but only 6.6% would always do so in the prophylactic setting. While generally perceived that the rate of SLN positivity in the setting of pure DCIS and prophylactic mastectomy was <5% (96.9% and 99.5%, respectively), 61.8% of surgeons who reported "always" performing SLNB in the setting of DCIS treated with mastectomy stated they "never" performed a SLNB for prophylactic mastectomy.

CONCLUSION

SLNB practice patterns for these low risk settings are disparate. Consensus is required to rationalize practice.

The nuclear coactivator amplified in breast cancer 1 maintains tumor-initiating cells during development of ductal carcinoma in situ

The key molecular events required for the formation of Ductal Carcinoma in Situ (DCIS) and its progression to invasive breast carcinoma have not been defined. Here we show that the nuclear receptor coactivator Amplified In Breast cancer 1 (AIB1) is expressed at low levels in normal breast but is highly expressed in DCIS lesions. This is of significance since reduction of AIB1 in human MCFDCIS cells restored a more normal 3D mammary acinar structure. Reduction of AIB1 in MCFDCIS cells, both prior to DCIS development or in existing MCFDCIS lesions in vivo, inhibited tumor growth and led to smaller, necrotic lesions. AIB1 reduction in MCFDCIS cells was correlated with significant reduction in the CD24−/CD44+ Breast Cancer Initiating Cells (BCIC) population, and a decrease in myoepithelial progenitor cells in the DCIS lesions in vitro and in vivo. Loss of AIB1 in MCFDCIS cells was also accompanied by a loss of expression of NOTCH 2, 3 and 4, JAG2, HES1, GATA3, HER2 and HER3 in vivo. These signaling molecules have been associated with differentiation of breast epithelial progenitor cells. These data indicate that AIB1 plays a central role in the initiation and maintenance of DCIS and that reduction of AIB1 causes loss of BCIC, loss of components of the NOTCH, HER2 and HER3 signaling pathways and fewer DCIS myoepithelial progenitor cells in vivo. We propose that increased expression of AIB1, through maintenance of BCIC, facilitates formation of DCIS, a necessary step prior to development of invasive disease.

Utility of intraoperative frozen section examination of sentinel lymph nodes in ductal carcinoma in situ of the breast

BACKGROUND

Intraoperative frozen section (IFS) examination of sentinel lymph nodes (SLN) is useful in selecting patients with invasive breast cancer for immediate axillary lymph node dissection. However, whether IFS evaluation of the SLNs in ductal carcinoma in situ (DCIS) of the breast has any value has not been previously assessed.

METHODS

Clinicopathologic data from patients with DCIS who underwent resection with SLN biopsy (2004-2010) were collected to assess the sensitivity, specificity, and accuracy of IFS, and its impact on axillary management.

RESULTS

A total of 267 patients with DCIS underwent resection with SLN biopsy and IFS evaluation. Preoperative pathology was DCIS (n = 231), DCIS with microinvasion (n = 24), and DCIS with other lesions (n = 12). Fifty-two (19.5%) patients had invasive breast cancer on final pathology. SLN metastases were identified in 13 (4.8%) patients; however, only 4 (1.5%) were IFS positive. IFS examination was negative in 263 (98.5%) patients. Among patients with SLN metastases, the most common pattern of metastases was either micrometastasis (n = 6) or immunohistochemistry-positive individual tumor cells (n = 4), whereas 3 patients had a macrometastasis. IFS examination was falsely negative in 9 of these 13 patients for a false-negative rate of 69.3%, and a sensitivity and specificity of 31% and 100% respectively. Nine of the 13 patients underwent axillary lymph node dissection and only 1 patient had further axillary metastasis.

CONCLUSIONS

SLN metastases in DCIS is rare and most commonly involves SLN micrometastasis or immunohistochemistry-positive individual tumor cells. SLN IFS evaluation in DCIS has a low yield and sensitivity, and can be safely omitted to reduce operative duration and cost.

Risk predictors of underestimation and the need for sentinel node biopsy in patients diagnosed with ductal carcinoma in situ by preoperative needle biopsy

BACKGROUND

Diagnosis of ductal carcinoma in situ (DCIS) by core needle biopsy showed a high rate of underestimation of invasiveness, and performing sentinel lymph node biopsy (SLNB) in DCIS patients was controversial.

METHODS

We analyzed 340 DCIS patients who were diagnosed by needle biopsies. Final pathology and clinicopathological features were reviewed. Predictors were accessed using the Chi-square test and a binary logistic regression model.

RESULTS

The overall DCIS underestimation rate was 42.6%. The underestimation was significantly related to the palpability, mass or calcification by ultrasonography, grade, suspicious microinvasion, and biopsy method in univariate analysis. In multivariate analysis, palpability, ultrasonographic calcification or mass, suspicious microinvasion, and core needle biopsy were independent predictors of underestimation of invasive cancer. In cases with one or no risk predictors, the underestimation rate was 14.3%, whereas, in those with five predictors, it increased to 90.9%. Among 144 invasive cancer patients who underwent axillary staging, 15.4% had node metastasis.

CONCLUSIONS

DCIS diagnosed by preoperative needle biopsy has a high probability of underestimation, and 15% of invasive cancer patients have node metastasis. SLNB may be justified in DCIS patients undergoing needle biopsies, and caution should be exercised in omitting SLNB in patients with one or no risk predictors.

Regulation of DCIS to invasive breast cancer progression by Singleminded-2s (SIM2s)

Singleminded-2s (SIM2s) is a member of the bHLH/PAS family of transcription factors and a key regulator of mammary epithelial cell differentiation. SIM2s is highly expressed in mammary epithelial cells and down regulated in human breast cancer. Loss of Sim2s causes aberrant mouse mammary ductal development with features suggestive of malignant transformation, whereas over-expression of SIM2s promotes precocious alveolar differentiation in nulliparous mouse mammary glands, suggesting that SIM2s is required for establishing and enhancing mammary gland differentiation. To test the hypothesis that SIM2s regulates tumor cell differentiation, we analyzed SIM2s expression in human primary breast ductal carcinoma in situ (DCIS) samples and found that SIM2s is lost with progression from DCIS to invasive ductal cancer (IDC). Utilizing a MCF10DCIS.COM progression model, we have shown that SIM2s expression is decreased in MCF10DCIS.COM cells compared to MCF10A cells and reestablishment of SIM2s in MCF10DCIS.COM cells significantly inhibits growth and invasion in vitro and in vivo. Analysis of SIM2s-MCF10DCIS.com tumors showed that SIM2s promoted a more differentiated tumor phenotype including the expression of a broad range of luminal markers (CSN2 (β-casein), CDH1 (E-cadherin), and KER18 (keratin-18)) and suppressed genes associated with stem cell maintenance and a basal phenotype (SMO (smoothened), p63, SLUG (snail-2), KER14 (keratin-14) and VIM (vimentin)). Furthermore, loss of SIM2s expression in MCF10DCIS.COM xenografts resulted in a more invasive phenotype and increased lung metastasis likely due to an increase in hedgehog signaling and matrix metalloproteinase expression. Together, these exciting new data support a role for SIM2s in promoting human breast tumor differentiation and maintaining epithelial integrity.

Sentinel node biopsy is not a standard procedure in ductal carcinoma in situ of the breast: the experience of the European institute of oncology on 854 patients in 10 years

OBJECTIVE

The aim of this study is to assess the role of sentinel lymph node (SLN) biopsy in patients with pure ductal carcinoma in situ of the breast (DCIS) as a rationale for recommending the best managing option for the treatment of such patients in daily practice.

SUMMARY BACKGROUND DATA

DCIS cannot give rise to axillary metastases by definition. Axillary dissection is therefore not indicated. The role of SLN biopsy in the management of DCIS has not yet been established.

METHODS

From March 1996 to September 2006, 854 patients with pure DCIS underwent SLN biopsy at the European Institute of Oncology. Clinical and pathologic data were prospectively collected. When previous surgery or stereotactic biopsy had been performed elsewhere, all the histopathological preparations were reviewed. Patients with microinvasion were excluded from this investigation. Lymphatic mapping was performed using a radiocolloid technique.

RESULTS

SLN metastases were detected in 12 (1.4%) DCIS patients. In 7 cases, only micrometastases (<2 mm) were diagnosed and in 5 cases macrometastases. In addition, isolated tumoral cells (ITC) (<0.2 mm) were identified in 4 additional patients. Eleven patients underwent complete axillary dissection. None of these patients had additional positive axillary lymph nodes.

CONCLUSIONS

Because of the low prevalence of metastatic involvement, SLN biopsy should not be considered a standard procedure in the treatment of all patients with DCIS. The sole criteria for proposing SLN biopsy in DCIS should be when there exists any uncertainty regarding the presence of invasive foci at definitive histology.

Expression patterns of lymphangiogenic and angiogenic factors in a model of breast ductal carcinoma in situ

BACKGROUND

Foci of invasion are found in greater than 20% of excised specimens of breast ductal carcinoma in situ (DCIS). Since lymphangiogenesis markers are associated with the potential for increased lymph node metastasis, the purpose of the current study was to determine expression of lymphangiogenesis molecular markers in a model of aggressive DCIS.

METHODS

From the MCF10A xenograft model, comedo type MCF10DCIS.com cells, premalignant MCF10AT, and invasive MCF10CA1a.cl1 cells were tested. Invasion was tested by Matrigel invasion assays (Becton-Dickinson, Bedford, MA). Gene expression was determined by reverse transcriptase-polymerase chain reaction and protein expression by immunoblot, normalized to beta-actin.

RESULTS

MCF10DCIS.com cells were 4-fold more invasive than MCF10AT cells (P < .01), and expressed several-fold more mRNA and protein than MCF10AT and MCF10CA1a.cl1 cells for vascular endothelial growth factor C, vascular endothelial growth factor D, and lymphatic vessel endothelial hyaluronan receptor 1 (P < .01).

CONCLUSIONS

A subset of comedo-type DCIS cells are invasive, and expression of lymphangiogenesis markers is greater at the mRNA and protein levels than by invasive cancer cells (P < .01). These additional molecular markers may characterize aggressive DCIS more precisely.