Pathological Evaluation of Sentinel Lymph Node Biopsy in Breast Cancer N. Krishnani Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow These PowerPoint presentations are free to download only for academic purposes, with due acknowledgements to authors and this website.

Sentinel Lymph Node First node to which lymph drainage and metastasis from breast cancer occurs Central group of level I (most common) Level II or III Intramammary Interpectoral or internal mammary node Proceedings of the Consensus Conference on Role of SLNB, 2001 Philadelphia

Sentinel Lymph Node Represent the entire nodal basin Most likely to contain tumor if metastasis has occurred If sentinel nodes are patholgically benign, all of the other axillary nodes can be considered tumor free SLNB is suitable replacement for axillary dissection as a staging and diagnostic procedure in T1 andT2 breast cancers

Sentinel Lymph Node Approximately 40% of operable breast cancer have axillary disease according to conventional histological methods StagePositive SLN T1a 4.3% T1b19.5% T1c23.8% T248.9% T366.7%

Inclusion and Exclusion Criteria Stage T1 or T2 disease without palpable nodal metastases Palpable axillary node metastases Multifocal breast cancer Pregnancy or currently breast feeding Prior major breast or axillary operations Allergies to blue dye or radiocolloid Proceedings of the Consensus Conference on Role of SLNB, 2001 Philadelphia

Sentinel Node Biopsy in Ductal Carcinoma In-situ Not indicated in mammographically detected DCIS or incidental finding. Indications: Palpable mass Large areas of calcification large lumpectomy High grade with or without comedo necrosis (microinvasion may be overlooked because of the area of disease is so large)

Handling of Specimen Measured and cut along its longitudinal axis into 2 mm- thick sections Gross examination to detect focal lesions Each 2 mm thick sections be cut at three levels Imprint cytology smears are prepared Remaining lymph node sections are then submitted for paraffin section histology Each paraffin block should be sectioned at 3 levels Report include individual cell / colonies / large size and location of malignant cells Proceedings of the Consensus Conference on Role of SLNB, 2001 Philadelphia

Am J Surg Pathol 2003;27(3): mm 2 mm

Am J Surg Pathol 2003; 27(3):

Metastases Macrometastases: Any tumor deposit > 2mm Micrometastases: Cohesive cluster of malignant cells, 0.2 mm and upto and including 2.0 mm in diameter. Indicate residual disease in approx. 10% of patients Sub-micrometastases: Clusters of malignant cells measuring less than 0.2 mm. Seen by IHC No clinical significance and highly unlikely to be associated with significant residual metastasis and predict an adverse outcome

Frozen Section Advantages Interpretation of nodal architecture available More specific diagnosis possible Size of metastatic focus measurable Can be complemented by rapid IHC Histologists are more familiar with the method Disadvantages Relatively time-consuming More expensive Freezing artifacts Some tissue is lost More expensive

Imprint Cytology Advantages Simple / cheap / rapid Interpretation of cytological / nuclear details available Avoid tissue loss Can be complemented by IHC Disadvantages Size and area of metastatic focus not detectable More indeterminate / deferred diagnoses Need special training to interpret Can not differentiate between micro and macrometastases

Authors H&E sections NAccuracySensitivitySpecificityFalse- negative Canavese et al Schneebaum et al Not described Koller et al3 consequti Imot et alNot described Noguchi et al Noguchi et al.> Noguchi et al2 mm interval Motomura et al Intraoperative Frozen-section Diagnosis

AuthorsNStudy designStd. Methods Upgraded by alternative methods Turner et al522 HE at 40 mm interval Vs 2 HE at 160 mm interval 195 Nahrig et al401 HE vs 4 additional HE at 150 mm intervals 4518 Torrenga et al2501HE vs additional 4 HE at 250 mm interval 284 Multiple Levels of H&E Sections

AuthorsNo. of Sections NAccuracySensitivitySpecificityFalse- Negative rate Moriya et al Rubio et al Ratan- et al Motomura et al2 mm interval Henry et al> Karamlou et al Intraoperative Imprint Cytology

Intraoperative Cytology Diagnostic accuracy did not exceed that of frozen section Occasional false positive case Concordance rate is approx. 90% When both method employed, diagnostic accuracy improve Takeshi Nagashima et al, Acta Cytol 2003;47:

Immunohistochemical Technique More accurate and used as adjunct to routine stain Antibody to cytokeratin used to detect small focus of malignant cells (Micrometastases or isolated tumor cells) False positive Benign transport of breast epithelium Degenerating cells in transit Dendritic cells Macrophages Epidermal squamous cells

AuthorsNStudy designStd Method Upgrade by IHC Czemiecki et al411HE Vs 4 levels of IHC 297 Noguchi et al621HE vs IHC392 Pendas et al4781HE vs IHC199 Kowolik et al332HE vs IHC2412 Mann et al511HE vs IHC20 Wong et al9731HE vs 2 levels of IHC 116 Torrenga et al2501HE vs IHC282 Torrenga et al2501 HE vs 4levels of IHC 287 Immunohitochemical Staining

Probability of non-SLN metastasis will be less than 0.1% if SLN negativity is confirmed by both H&E and immunohistochemistry Turner et al: Am J Surg Pathol 1999;23: H&E and Immunohistochemistry

What is the significance of occult metastases in terms of prognosis What is the significance of occult metastases in terms of predicting further nodal involvement (approx. 12%) Do these patient stand to benefit from completion axillary lymph node dissection and / or systemic chemotherapy Implications of Micrometastases Seen Only on Immunohistochemistry

Implications of Micrometastasies Seen Only on Immunohistochemistry Data are inconclusive at this time Additional studies are needed in order to establish the role of IHC detected lymph node metastases

Recommendations Ignore the presence of isolated tumor cells Either refrain from examining SLN by IHC or address on case by case basis Allweis et al, Breast 2003;12: and European Consensus group for Breast Screening Pathology

Recommendations Standard practice and, the pathology report should state only whether metastasis are found on H&E stained slide IHC may be performed when the H&E stained slides have suspicious cells that are equivocal Cytokeratin positive malignant cells be quantified Proceedings of the Consensus Conference on Role of SLNB, 2001 Philadelphia

Recommendations Adjuvant therapy, either chemotherapy or hormonal treatment (or for completion axillary dissection or axillary radiation) should not be made solely on the basis of information obtained by IHC of sentinel lymph node Proceedings of the Consensus Conference on Role of SLNB, 2001 Philadelphia

Molecular Analysis Assesment by reverse transcription-polymerase chain reaction (RT-PCR) More sensitive than immunohistochemistry Specific markers are lacking, and false negative tests Relevance is even more debatable than occult metastasis detected by immunohistochemistry Results are highly variable and high rate of upstaging (14-50%) Experimental assessment Not feasible in all pathology lab

Summary of Consensus Intraoperative assessment of SNs is strongly recommended Careful handling specimen and cut node into 2 mm section and examine for any focal lesion Step sectioning or multiple level assessment should be used, although the optimal distance between these step is controversial Choice of method should be institutional depending on the resources Imprint cytology should be done in conjunction with frozen section

Summary of Consensus Immunohistochemistry is optional in routine patient management Molecular analysis be restricted to research purposes as controversies over the interpretation and the lack of specific markers