Mitotic Index Is Predictive for Survival for Canine Cutaneous Mast Cell Tumors

Abstract

Abstract. Mitotic index (MI) is an indirect measure of cell proliferation that has been demonstrated to be a strong predictor of outcome for several human and canine cancers. The purpose of this study was to evaluate the utility of MI as a predictor of biologic behavior and survival in dogs with cutaneous mast cell tumors (MCTs). Medical records from 148 dogs with histologically confirmed MCTs were reviewed. Information regarding tumor grade, local recurrence, metastatic disease, date of death/last follow-up, and outcome was obtained. The region of the tumor with the highest overall mitotic activity was chosen for evaluation, and the MI value was defined as the number of mitotic figures/10 high-power fields (4003, 2.7 mm 2 ). A Cox proportional hazards regression model was used to compare MI with survival data. A Mann-Whitney test was used to compare MI on the basis of the development of local recurrence and metastatic disease. The MI correlated directly with tumor grade (P , .0001). The median survival time for dogs with an MI #5 was significantly longer (70 months) than for those with an MI .5 (2 months), regardless of grade (P , .001). For grade II tumors with an MI #5, the median survival time (MST) was 70 months, compared with 5 months for those with an MI .5 (P , .001). For grade III tumors with an MI #5, the MST was not reached, compared with ,2 months for those with an MI .5 (P , .001). In conclusion, MI is a strong predictor of overall survival for dogs with cutaneous MCTs and should be included as a prognostic indicator when determining therapeutic options.

Mast Cell Tumors in a Llama (Lama Glama)

“…A histologic grading system has also been established for MCTs in dogs and may be associated with prognosis along with other proliferation markers, such as mitotic index, proliferating cell nuclear antigen, and argyrophil nucleolar organizer region. 20,23,24 Mast cell tumors in cats and human beings often occur as a systemic disease. The term systemic mastocytosis is used in human medicine to describe mastocytosis in blood, bone marrow, lymph nodes, and several internal organs.…”

Outcome of adjuvant chemotherapy with lomustine, vinblastine and chlorambucil on management of canine mast cell tumour of high to intermediate risk

“…Once the mitotic count is a wll established prognostic factor there was no patient in the intermediate-to-low-risk groups with a mitotic count higher than five in 10 high power fields (Romansik et al, 2007). Nevertheless, a Ki-67 index higher than 1.8% was confirmed in 94,3% of all cases, and in 91,1% of the intermediate-tolow risk patients, and this may be related to a low specificity of this prognostic factor, when compared to mitotic count, as described by van Lelyveld et al (2015).…”

“…A high risk of recurrence or metastasis is associated with tumours classified as a grade 3 MCT according to the Patnaik grading scheme, but also for the Patnaik intermediate grade, whenever there is a lymph node or distant metastasis and / or high growth fraction estimated by the mitotic count or Ki-67 immunoexpression (Romansik et al, 2007;Blackwood et al, 2012;London and Thamm, 2013;Miller et al, 2014), and for the MCT located in the mucousa or mucocutaneous junctions (London and Thamm, 2013). Other prognostic factors, may also be important for disease progression, such as tumour location (scrotum, prepuce, perineum or vulva), breed (London and Thamm, 2013) and KITr pattern expression (Kiupel et al, 2004).…”

Comparative analysis of markers of cell proliferation in canine mast cell tumours according to current classifications

“…High proliferation potential is associated with faster growth of the tumour, and is often associated with greater risk for local recurrence and formation of distant metastases. Therefore, the markers of cell proliferation are often used to distinguish between benign and malignant lesions (Romansik et al 2007). …”