Metastasis of Mammary Carcinoma in Bitches: Evaluation of the Sentinel Lymph Node Technique

Abstract

In recent years the development of extremely accurate techniques for the removal of lymph nodes has been seen, such as the Sentinel Lymph Node Biopsy (SLNB) technique. The technique is based on the staggered progression occurring in the lymphatic drainage of neoplasias, and is currently the main prognostic and diagnostic factor in women suffering from mammary carcinoma. This research aims at assessing the sentinel lymph node biopsy accuracy in female dogs suffering from mammary carcinoma. Forty-one dogs with cytological diagnosis of the tumor were used in the research. After injecting a Patent Blue V dye, mastectomy was conducted jointly with lymphadenectomy (for both sentinel and non-sentinel lymph nodes). The material was then serially sectioned and microscopically evaluated by routine H&E stain and immunohistochemical study with the markers for pancytokeratin AE1/AE3 and myoepithelial cells CK14. The study revealed that 46.3% (19/41) of the animals presented nodal metastasis. The sensitivity and specificity values found for SLNB were respectively 89.5% and 100%, with a kappa coefficient of 0.90 and p < 0.0001. Therefore, the SLNB technique offers high sensitivity in the early detection of metastases, allowing higher precision in the staging of oncological patients and, therefore, offering higher chances of survival.

Investigation of the utility of lymph node fine‐needle aspiration cytology for the staging of malignant solid tumors in dogs

“…Among these tumors, the prevalence of metastases within several LNs was 23.9%, suggesting that staging should not always be limited to the assessment of a single LN. This is in agreement with the results obtained with routine extirpation of bilateral mandibular and medial retropharyngeal lymphadenectomy for the staging of head‐based tumors, and with the use of sentinel LNs . It remains for further research to investigate whether such cases have a worse prognosis when compared with those cases that have solitary LN metastases.…”

“…This is in agreement with the results obtained with routine extirpation of bilateral mandibular and medial retropharyngeal lymphadenectomy for the staging of head-based tumors, 38 and with the use of sentinel LNs. 21,22,39,40 It remains for further research to investigate whether such cases have a worse prognosis when compared with those cases that have solitary LN metastases. Such results could also be significant from a therapeutic aspect, in particular, when surgical excision or irradiation of the metastatic lymph node(s) are part of the treatment plan.…”

“…We also aimed to elucidate the impact of nondiagnostic FNACs in the routine staging of canine solid tumors, a limitation that has not been assessed previously. Similarly, previous studies assessed only one LN for metastatic disease, which was usually the regional LN, although tumors can metastasize to several LNs, and sometimes “skip” the anticipated regional LN . In our study, we assessed several LNs and the impact that this such wider sampling had on staging results.…”

Linfonodo axilar como sentinela de neoplasia mamária em cadelas

“…Acredita-se que a recorrência seria devido às metástases que não foram detectadas pelos métodos de rotina e cujos pacientes foram subestadiados (Salles et al 2009), o que poderia ser extrapolado para pequenos animais, visto que duas pacientes só tiveram a metástase diagnosticada pela imuno-histoquímica. Apesar da alta sensibilidade encontrada, a utilização exclusiva da coloração rotineira de hematoxilina e eosina pode dificultar a identificação de células metastáticas isoladas, conduzindo a diagnósticos falso-negativos (Piato et al 2008, Beserra et al 2016 A correlação da ocorrência de metástase em linfonodo axilar considerando o intervalo de confiança 95% só foi significativa na mama torácica cranial (M1), a qual das 11 cadelas com neoplasia nessa mama, quatro foram positivas. Isso corresponde a 36,4% apresentando metástase.…”

“…Cada vez mais tem sido observado que quando há presença de tumor na cadeia mamária, a drenagem linfática não segue o padrão descrito pela literatura, o que se deve a linfangiogênese estabelecida pela presença do neoplasma. Estudos demonstram que linfonodos correspondentes a regiões que possuem neoplasia mesmo sem apresentar alteração de tamanho e consistência podem já estar com metástase (Beserra et al 2016).…”