Re-evaluating the role of sentinel lymph node biopsy in microinvasive breast carcinoma

Abstract

The role of sentinel lymph node biopsy in microinvasive breast carcinoma is unclear. We examined the incidence of lymph node metastasis in patients with microinvasive carcinoma who underwent surgery at our institution. Retrospective review of our pathology database was performed (1994-2012). Of 7000 patients surgically treated for invasive breast carcinoma, 99 (1%) were classified as microinvasive carcinoma. Axillary staging was performed in 81 patients (64, sentinel lymph node biopsy; 17, axillary lymph node excision). Seven cases (9%) showed isolated tumor/epithelial cells in sentinel nodes. Three of these seven cases showed reactive changes in lymph nodes, papillary lesions in the breast with or without displaced epithelial cells within biopsy site tract, or immunohistochemical (estrogen receptor, progesterone receptor, and HER2) discordance between the primary tumor in the breast and epithelial cells in the lymph node, consistent with iatrogenically transported epithelial cells rather than true metastasis. The remaining four cases included two cases, each with a single cytokeratin-positive cell in the subcapsular sinus detected by immunohistochemistry only, and two cases with isolated tumor cells singly and in small clusters (<20 cells per cross-section) by hematoxylin and eosin and immunohistochemistry. The exact nature of cytokeratin-positive cells in the former two cases could not be determined and might still have represented iatrogenically displaced cells. In the final analysis, only two cases (3%) had isolated tumor cells. Three of these four cases had additional axillary lymph nodes excised, which were all negative for tumor cells. At a median follow-up of 37 months (range 6-199 months), none of these patients had axillary recurrences. Our results show very low incidence of sentinel lymph node involvement (3%), only as isolated tumor cells, in microinvasive carcinoma patients. None of our cases showed micrometastases or macrometastasis. We recommend reassessment of the routine practice of sentinel lymph node biopsy in patients with microinvasive carcinoma.

Sentinel lymph node biopsy in microinvasive ductal carcinomain situ

“…The findings of this study indicate that SLNB may not be useful in microinvasive DCIS owing to the low risk of lymph node metastasis and good prognosis. The good prognosis may be explained by the theory that the major rate of positivity could correspond to an iatrogenic transit of tumour/epithelial cells to lymph nodes, without the significance of real metastasis. Level 1 evidence shows that, in patients with SLN‐positive breast cancer, axillary dissection may be avoided when there is a low axillary metastatic burden (Z0011) and in patients undergoing BCS with radiotherapy; this also supports the conclusion that SLNB in microinvasive DCIS may not be useful.…”

“…If staging the axilla in DCIS is accepted globally in the above conditions, what remains controversial is the real value of staging the axilla with SLNB in microinvasive DCIS, as reviewed in Table . The incidence of axillary metastasis in sentinel nodes varies in studies from approximately 2 to 20 per cent.…”

Clinical characteristics of breast ductal carcinoma in situ with microinvasion: a narrative review

“…The rate of axillary lymph node metastasis is approximately 0% to 20% in DCIS-MI. [29][30][31][32][33][34][35][36] It is crucial to distinguish between clinical node positivity and node negativity with positive sentinel lymph node biopsy (SLNB). SLNB is a standard examination for patients with breast cancer and clinically negative lymph nodes.…”

“…However, in a recent study investigating the role of SLNB in DCIS-MI, Magnoni and colleagues 33 found that SLNB was not a good predictor of the need for ALND. Among 257 women with microinvasive breast cancer, 87.9% (266) had negative SLNB, and 12.1% (31) had positive SLNB. Among the 31 patients with positive SLNB, 5, 14, and 12 patients had macrometastases, micrometastases, and isolated tumor cells in sentinel nodes, respectively.…”

The Sentinel Node with Isolated Breast Tumor Cells or Micrometastases. Benefits and Risks of Axillary Dissection

“…The clinical and prognostic significance of a minimal tumor burden in the axilla of breast cancer patients is unclear (6). ITCs are defined as small clusters of tumor cells not greater than 0,2 mm or clusters of cells not exceeding 200 cells in a single lymph node cross section.…”