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Comparison between Ki‐67 index and mitotic index for predicting outcome in canine mast cell tumours
Author(s) -
van Lelyveld S.,
Warland J.,
Miller R.,
Maw H.,
Foale R.,
Goodfellow M.,
Dobson J.
Publication year - 2015
Publication title -
journal of small animal practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 67
eISSN - 1748-5827
pISSN - 0022-4510
DOI - 10.1111/jsap.12320
Subject(s) - mitotic index , medicine , mast cell , clinical significance , index (typography) , mitosis , pathology , oncology , immunology , biology , world wide web , computer science , microbiology and biotechnology
OBJECTIVES To assess correlation between Ki67 index and mitotic index and determine which more accurately predicts survival in canine mast cell tumours. METHODS Retrospective analysis of cases from three UK referral hospitals. Correlation between Ki67 index and mitotic index was assessed and survival analysis performed. RESULTS A total of 162 dogs were included: 57 dogs died with 37 due to mast cell tumour. Correlation between Ki67 index and mitotic index was moderate, while the agreement was poor. A high Ki67 index was considered sensitive (86 · 5%) at predicting mast cell tumour‐related death, but poorly specific (57 · 9%). Mitotic index(>5) was poorly sensitive (32 · 4%), but highly specific (96%). A mitotic index of ê 2 had a 75 · 7% sensitivity and an 80 · 0% specificity. Ki67 index showed a statistically significant survival difference within the mitotic index <2 (P = 0 · 009) group. Ki67 index did not predict survival rate in tumours with mitotic index of ê 2. CLINICAL RELEVANCE Correlation between Ki67 and mitotic index is moderate. High mitotic index accurately predicted death, but many dogs with low mitotic index also died. Low Ki67 accurately predicted survival, but high Ki67 should not be considered a poor prognostic indicator. A three‐tier mitotic index assessment may more accurately predict death due to mast cell tumour.