Sentinel Node Biopsy Examination for Breast Cancer in a Routine Laboratory Practice: Results of a Pilot Study

Abstract

Background: Examination of sentinel lymph node (SLN) biopsies provides accurate nodal staging for breast cancer and plays a key role in patient management. Procurement of SLNs and the methods used to process specimens are equally important. Increasing the level of detail in histopathological examination of SLNs increases detection of metastatic tumours but will also increase the burden of busy laboratories and thus may not be carried out routinely. Recommendation of a reasonable standard in SLN examination is required to ensure high sensitivity of results while maintaining a manageable practice workload. Materials and Methods: Twenty-four patients with clinically node-negative breast cancer were recruited. Combined radiotracer and blue dye methods were used for identification of SLNs. The nodes were thinly sliced and embedded. Serial sectioning and immunohistochemical (IHC) staining against AE1/AE3 were performed if initial H&E sections of the blocks were negative. Results: SLNs were successfully identified in all patients. Ten cases had nodal metastases with 7 detected in SLNs and 3 detected only in axillary nodes (false negative rate, FNR=30%). Some 5 out of 7 metastatic lesions in the SLNs (71.4%) were detected in initial sections of the thinly sliced tissue. Serial sectioning detected the remaining two cases with either micrometastases or isolated tumour cells (ITC). Conclusions: Thin slicing of tissue to 3-5mm thickness and serial sectioning improved the detection of micro and macro-metastases but the additional burden of serial sectioning gave low yield of micrometastases or ITC and may not be cost effective. IHC validation did not further increase sensitivity of detection. Therefore its use should only be limited to confirmation of suspicious lesions. False negative cases where SLNs were not involved could be due to skipped metastases to non-sentinel nodes or poor technique during procurement, resulting in missed detection of actual SLNs.

Application of automated image analysis reduces the workload of manual screening of sentinel lymph node biopsies in breast cancer

“…At the same time, studies have shown a need for thorough examination of all axillary SLNs in an attempt to eradicate any false-negative assessments, which only adds to the growing workload of pathologists and today's laboratories. 13,16 As a consequence, many laboratories have abandoned frozen section examination of SLNBs. 17 Standardization of tissue processing, IHC staining and optimal assessment with cost-effective methods for histopathological examination of SLNs is therefore necessary.…”

“…The SLNB technique introduces serial sectioning of SLNBs, in which up to nine SLNs and an average of two SLNs per patient have to be examined. At the same time, studies have shown a need for thorough examination of all axillary SLNs in an attempt to eradicate any false‐negative assessments, which only adds to the growing workload of pathologists and today's laboratories . As a consequence, many laboratories have abandoned frozen section examination of SLNBs …”

“…Standardization of tissue processing, IHC staining and optimal assessment with cost‐effective methods for histopathological examination of SLNs is therefore necessary. A modified procedure should be adapted for use in routine practice without unnecessary overstretching of the workload and the laboratory budget . Introduction of DIA and the SLNB algorithm as a screening tool to deal with the SLN challenge would help with these issues and free precious time that the pathologist could use on other important diagnostic tasks.…”

Clinical Significance of Metastasis or Micrometastasis to the Lymph Node Along the Superior Mesenteric Vein in Gastric Carcinoma: A Retrospective Analysis

“…According to the 6 th edition of International Union Against Cancer (UICC), lymph node metastasis (LNM) is classified into isolated tumor cells (ITC), micrometastasis (MI), and macrometastasis (MA), depending on the size of the metastatic deposit (5). Methods to investigate the presence of MI vary, from serial slices with hematoxylin and eosin (H&E) staining, immunohistochemical (IHC) staining, to real-time reverse transcription-polymerase chain reaction (RT-PCR) (6)(7)(8)(9). Cytokeratin is one component of the cytoskeleton of epithelial cells that is not present in normal lymph nodes, and its corresponding antibody is widely used to detect minute deposits of tumor cells in lymph nodes by IHC staining.…”