Pro: SLNB in DCIS

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.

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.