A imuno-histoquímica no linfonodo sentinela por câncer de mama: um estudo de 247 casos / Immunohistochemistry of sentinel lymph node in breast cancer: analysis of 247 cases

RESUMO

O objetivo deste trabalho foi determinar, em pacientes com carcinoma mamário, o valor da imuno-histoquímica (IHQ) na detecção de micrometástase, submicrometástase e células tumorais isoladas em linfonodo sentinela (LNS) negativo na hematoxilina e eosina (HE). Foram estudados 247 LNS axilares diagnosticados entre 23 de agosto de 2000 e 27 de dezembro de 2003. O LNS fixado em formol foi seccionado em fatias de 2 mm de espessura. Após inclusão em parafina, de cada bloco realizou-se três cortes de 5 mm, com intervalos de 40 mm, corados na HE. Outros três cortes foram realizados em seqüência para IHQ (pancitoceratina AE1/AE3). Resultados: Os 247 LNS resultaram na HE 220 negativos (89%) e 27 positivos para metástases (11 %). Na IHQ 210 negativos (dos 220 casos negativos na HE) (concordância 96%) e 27 positivos (dos 27 casos positivos na HE). Nos 10 casos negativos na HE (4,5% dos negativos), a IHQ resultou positiva. Conclusão: A pesquisa de citoceratinas por IHQ no LNS negativo na HE permite detectar um subgrupo de pacientes portadores de micrometástases, de submicrometástases ou de células tumorais isoladas, representando em nossa casuística 4,5% dos linfonodos negativos.

ABSTRACT

The objective of this research was to assess the increased ratio of tumour detection detected by immunohistochemistry (IHC) in HE negative sentinel lymph nodes (SLN) of patients with breast cancer. We studied 247 SLN of patients with breast cancer reports from August 23rd 2000 to December 27th 2003.The formalin-fixed SLN was sectioned in tissue slices about 2 mm thick. Following paraffin embedding, three 5-llm-thick sections were cut from each slice and stained with HE. Another three sections were cut for IHC staining. Results: Of the 247 SLN, 220 were negative and 27 were positive for metastases with HE. IHC assays were positive in all HE-positive cases and negative in 210 of 220 HE-negative cases (concordance = 96%). The other 10 HE negative cases (4.5% of negative cases) were IHC positive. Comparisons of data from HE-stained sections and cytokeratin immunohistochemistry showed an overall sensitivity of 73% with 100% specificity. Conclusions: The addition of IHC in the study of serial sections of HE stained preparations from SLN negative patients with breast cancer increased the percentage of detection of metastatic tumour cells. Moreover, it identified subgroup of breast cancer with micrometastases that were stained only by IHC, representing, in our series, 4.5% of HE negative SLNs.