Diagnostic efficacy of smear cytology and Robinson’s cytological grading of canine mammary tumors with respect to histopathology, cytomorphometry, metastases and overall survival

Abstract

Cytology is a simple, rapid, and inexpensive method used for pre-operative diagnosis of canine mammary tumors (CMTs) in veterinary practice. Studies related to human breast cancer showed the Robinson’s grading system—established for invasive ductal carcinoma, not otherwise specified (IDC, NOS) and used on cytological material—to not only closely correspond to the histopathological grading but also be helpful in assessing prognosis and selecting most suitable treatments before surgery. The objectives of this study were: to evaluate the accuracy of cytological diagnosis and cytological Robinson’s grading system compared to the histopathological examination of CMTs; to compare of cytological features and cytomorphometric parameters with tumor behavior, as well as cytological and histological grading; and to determine an association of the Robinson’s grading system and cytological background details with metastases, and patients’ survival. We report substantial diagnostic accuracy in detecting simple types and high grade tumors. Cytological diagnosis of tumor behavior showed relatively low sensitivity and specificity compared to human studies, and this might be caused by the heterogeneous morphology of CMTs. The presence of mucosecretory material and extracellular matrix was not significantly associated with tumor behavior. We report a positive correlation between both grading systems and cytological features (included in Robinson’s grading), the presence of necrotic debris, inflammation, and red blood cells. A negative correlation was determined only for the presence of extracellular matrix. The univariate and multivariate analyses confirmed a significantly higher risk of developing metastasis and shorter overall survival for dogs with tumors of grade 2 or 3 on cytology. In addition, these tumors were the most common cause of CMT-related deaths in dogs. Taken together, our findings suggest that the Robinson’s method of cytological grading applied for malignant CMTs evaluated in cytological smears regardless of tumor type can be adapted to veterinary cytology. Additionally, some background features seem to aid malignancy assessment.

Relationship of obesity with clinical and laboratory changes in female dogs with mammary neoplasia

“…In this study, 84.61% of the samples analyzed had adequate cellularity, which corroborated the detection of malignant and/or benign features in cytology, and 90.9% had the diagnosis of tumor behavior compatible with histopathology. Dolka et al (2018) found correspondence between the two methods in 86.3%, which differed little from the data found in this study.…”

“…Malignant neoplasias were more prevalent in this study, as well as in the study by Horta et al (2014) when evaluating 391 lesions, of which 56% were malignant neoplasias and 31% were benign neoplasias. Dolka et al (2018) analyzed 18 tumors and, of those, 75.3% were malignant and 24.7% benign. O diagnóstico de tumores malignos e benignos, neste estudo, foi levado em consideração devido ao baixo número amostral, porém considera-se relevante o desenvolvimento de outras pesquisas para avaliar as características de cada tipo histológico.…”

“…Mammary tumors are the most common types of neoplasia in female dogs, representing more than 50% of the cases, being 50% to 70% diagnosed as malignant, with metastatization capability for regional lymph nodes and lung. Consequently, the occurrence of mammary neoplasia in domestic animals is a subject addressed worldwide (Lana et al 2007, Szczubial et al 2012, Gundim et al 2016, Dolka et al 2018, Marconato et al 2019. In addition, cancer is the leading cause of death in elderly dogs and the second largest cause in companion animals (Horta et al 2012).…”

Mixed Mammary Carcinosarcoma in Domesticated Asian Palm Civet (Paradoxurus hermaphroditus).

“…In the clinic, a simple method to analyse and diagnose the mammary tumours in both human and animal is a cytological examination. However, this procedure is not satisfactory in canids because of the complex morphology of cells mammary tumours (Dolka et al, 2018). The histopathology and immunohistochemistry are known to be sufficient to analyse cells morphology and glycoprotein markers on the canine mammary tumours (Carvalho et al, 2016).…”

ROSE: Alternative for Cancelled and Inconclusive Cytopathologic Examinations, as Well as Professional Training at the UNESP-Botucatu Veterinary Hospital

“…Several Factors that may interfere and complicate the examination include: heterogeneous composition of tumors, incomplete clinical history, lack of standardization in the methodology, inter-observer variation, irregular distribution, cystic nature, small injuries, difficulties during the collection and presence of necrosis and inflammation [3] [4] [8]. As such, in about 5% to 15% of the cases, the Fine Needle Aspiration (FNA) biopsy did not reach a conclusive diagnosis, not because of the technique itself, but rather because of the inexperience of the pathologist or the characteristics of the injury [4] [8] [9]. Therefore, an alternative to increase quality in these cases is applying the ROSE (Rapid On-Site Evaluation) protocol, which consists in establishing standards to assure the sensitivity and specificity of the cytopathological exam without compromising its inherent quickness, considering all stages of the process, from requisition, collection, processing, reading and interpretation to issuing the diagnosis, as well as the determining of the previous classification of the injury [10].…”