Minimal Involvement of Sentinel Lymph Node in Breast Carcinoma: Prevailing Concepts and Challenging Problems

Adjuvant chemotherapy for breast cancer patients with axillary lymph node micrometastases

BACKGROUND

The axillary lymph node status is one of the most important prognostic factors in patients with early breast cancer. However, the impact of axillary lymph node micrometastases on survival remains unclear. There are no consistent recommendations for adjuvant chemotherapy (CHT). In this context, we aimed to investigate the impact of micrometastases on the clinical outcome of breast cancer patients according to the adjuvant CHT performed.

PATIENTS AND METHODS

We conducted a retrospective population-based registry study of 26,465 patients aged between 24 and 97 years with primary breast cancer diagnosed between 2003 and 2017. Of these patients, 8856 with early breast cancer were eligible for analysis: 8316 (93.9%) were node negative and 540 (6.1%) had lymph node micrometastases.

RESULTS

The median follow-up was 7.2 years, with a confidence interval (CI) of 7.1-7.3 years. Patients with lymph node micrometastases (pN1mi) without adjuvant CHT have reduced 10-year overall survival (OS) and recurrence-free survival (RFS) compared to patients who had axillary lymph node micrometastases and received an adjuvant CHT. However, this effect disappeared after adjustment for age, tumor size and tumor grading. Furthermore, in the group of patients with lymph node micrometastases, the administration of adjuvant CHT did not improve OS or RFS, compared to patients with lymph node micrometastases without adjuvant CHT: hazard ratio for treated patients was 1.51 (95% CI 0.80-2.85, p = 0.208) for OS and 1.12 (95% CI 0.63-1.97, p = 0.705) for RFS.

CONCLUSION

Patients with axillary lymph node micrometastases showed a comparable outcome to node negative patients and their outcome was not significantly improved with CHT. Thus, axillary lymph node micrometastases should not be considered in the treatment decision.

Sentinel lymph node micrometastasis in human breast cancer: an update

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and advances in histopathological and molecular analysis techniques have been associated with an increase in micrometastasis (MM) detection rate. However, the clinical significance of sentinel lymph node micrometastasis (SLN MM) continues to be a subject of much debate. In this article we review the literature concerning SLN MM, with particular emphasis on the prognostic significance of SLN MM. The controversies regarding histopathological assessment, clinical relevance and management implications are also discussed.

METHODS

Literature review facilitated by Medline and PubMed databases. Cross referencing of the obtained articles was used to identify other relevant studies.

RESULTS

Published studies have reported divergent and rather conflicting results regarding the clinical significance and implications of axillary lymph node (ALN) MM in general and SLN MM in particular. Some earlier studies demonstrated no associations, however most recent studies have found SLN MM to be an indicator of poorer prognosis and to be associated with non-SLN involvement. The use of adjuvant chemotherapy and/or hormonal manipulation therapy is associated with an improved survival in patients with SLN MM. Complete ALND may be safely omitted provided that adjuvant systemic therapy recommendations are equal to patients with node-positive disease. However, optimal management of SLN MM is yet to conclude. Furthermore, the identification of MM remains largely dependent on the analytical technique employed and the use of immunohistochemistry (IHC) increases the detection rate of SLN MM. Discrepancies in the histopathological interpretation of TNM classification of SLN tumour burden do exist. Published studies were non-randomized and have significant limitations including a small sample size, limited follow-up period, and lack of standardization and reproducibility of pathological examination of the SLN.

CONCLUSION

Patients with SLN MM have a poorer prognosis than those who are SLN negative. Therapeutic recommendations regarding patients with SLN MM should be taken in the context of multidisciplinary team setting and in selected cases of SLN MM, complete ALND may be safely omitted. A better reproducibility of pathological interpretation of the TNM classification is required so that future therapeutic guidelines can be applied without confusion.

Clinical significance of sentinel lymph node isolated tumour cells in breast cancer. Breast Cancer Res Treat. 2011;127:325-334. [PMID: 21455668 DOI: 10.1007/s10549-011-1476-4]

The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the rate at which isolated tumour cells (ITC) are identified. However, their biological and clinical significance has been the subject of much debate. In this article we review the literature concerning SLNB with particular reference to ITC. The controversies regarding histopathological assessment, clinical relevance and management implications are explored. The literature review was facilitated by Medline, PubMed, Embase and Cochrane databases. Published studies have reported divergent results regarding the biological significance and clinical implications of ITC in general and SLN ITC in particular. Some studies demonstrate no associations, whilst others have found these to be indicators of poor prognosis, associated with non-SLN involvement, in addition to local recurrence and distant disease. Absolute consensus regarding the optimal analytical technique for SLN has yet to be reached, particularly concerning immunohistochemical (IHC) techniques targeting cytokeratins and contemporary molecular analysis. The clinical relevance of ITC within the SLN should be primarily determined by the magnitude of their impact on patient management and outcome measures. The modest up-staging within current classification systems is justified and reflects the marginally poorer prognosis for women with SLN ITC. Management need not be altered where further axillary treatment with surgical clearance or radiotherapy and systemic adjuvant treatment are already indicated. However, in the absence of level-1 guidance, each case requires discussion with regard to other tumour and patient related factors in the context of the multidisciplinary team. The identification of ITC remains highly dependent on the analytical technique employed and there exists potential for stage migration and impact on management decisions. Evidence supporting the routine analysis of deeper tissue sections by IHC is lacking and molecular technologies should be restricted to research purposes at present.

The efficient operation of the surgical pathology gross room

The gross room is the area where pathology specimens from operating rooms are transferred for pathology review and analysis, serving as the bridge between the treating physician and diagnostic surgical pathologist. Reaching the correct diagnosis for a specimen depends on the proper handling and processing of tissue transferred to this very busy area. We review here the basic function and management of the gross room including a brief discussion of common specimen types, biohazard exposure and safety, and collection of tissue for research.

The clinical significance of sentinel lymph node micrometastasis in breast cancer

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the rate at which micrometastases (MM) are identified. However, their significance has been the subject of much debate. In this article we review the literature concerning axillary lymph node (ALN) MM, with particular reference to SLNB. The controversies regarding histopathological assessment, clinical relevance and management implications are discussed.

METHODS

Literature review facilitated by Medline and PubMed databases.

RESULTS

Published studies have reported divergent results regarding the significance and implications of ALN MM in general and sentinel lymph node (SLN) MM in particular. Some studies demonstrate no associations, whilst others have found these to be indicators of poor prognosis, associated with non-SLN involvement, in addition to local and distant failure. Absolute consensus regarding the optimal analytical technique for SLNs has yet to be reached, particularly concerning immunohistochemical (IHC) techniques targeting cytokeratins and the utility of contemporary molecular analysis.

CONCLUSION

SLN MM are likely to represent an incremental detriment to prognosis and increased risk of non-SLN involvement, despite only modest up-staging within current classification systems. In the absence of level-1 guidance concerning the management of women with SLN MM, each case requires discussion with regard to other tumour and patient related factors in the context of the multidisciplinary team. Randomized studies are required to evaluate the prognostic significance and optimal management of each category of tumour burden within the SLN. The identification of MM remains highly dependent on the analytical technique employed and there exists potential for stage migration and impact on management decisions.

Minimal metastatic disease in sentinel lymph nodes in breast carcinoma: some modest proposals to refine criteria for "isolated tumor cells"

Axillary lymph node status is one of the most important prognostic factors in breast carcinoma. The weight of cumulative evidence suggests that the development of the sentinel lymph node (SLN) biopsy procedure has not only allowed for accurate lymph node-staging but has also helped avoid the morbidity of a full axillary dissection in those patients who are unlikely to have metastatic tumor in that location. The detection of metastases in SLNs is facilitated by the, now relatively routine, enhanced histopathologic examination via step-sectioning and immunohistochemistry. In clinical terms, the finding of a metastatic deposit that measures between 0.2 and 2 mm, that is, "micrometastasis" in a SLN is largely noncontroversial; however, the presence of smaller metastatic foci detected either by routine hematoxylin and eosin stain or by cytokeratin immunostain [<0.2 mm, ie, so-called "isolated tumor cells (ITCs)"] has remained problematic since the advent of the SLN biopsy. In this communication, attention is drawn to the broad morphologic range of metastatic disease in SLN that may be placed in the category of so-called ITC. To facilitate the reproducible classification of the various strata of minimal metastasis in sentinel lymph nodes, we recommend the following: (1) the term "isolated tumor cell" (note singular form) be restricted to cases that show the presence of only a single tumor cell. (2) In situations where there are multiple isolated single cells and/or cell cluster(s) present and each cluster measures<0.2 mm, the term "submicroscopic metastasis" be adopted and an actual count of tumor cells present may be given. (3) Restrict the use of the term micrometastasis to cases wherein the largest metastatic focus is larger than 0.2 mm but smaller than 2.0 mm.