Survival Time and Disease Free Interval in Dogs with Different Grade of Mast Cell Tumor

U radu je istraživana pojavnost mastocitoma u pasa ovisno o dobi pasmini, spolu i stupnju malignosti te vrijeme preživljavanja i vrijeme do ponovnog pojavljivanja bolesti (recidiva) u petogodišnjem razdoblju (od 1. siječnja. 2009. do 31. prosinca 2013). Tumori su dostavljeni na histopatološku dijagnostiku na Zavod za veterinarsku patologiju Veterinarskog fakulteta u Zagrebu. Dijagnosticirani u 123 životinje, ali su bila ukupno 133 tumora. Za praćenje vremena preživljavanja i vremena do pojave recidiva anketirani su vlasnici životinja te su podaci dobiveni za 77 životinja. U skupini od 77 pasa mastocitomi su bili najčešći u zlatnog retrivera, labrador retrivera, boksera i križanaca. Prosječna dob je bila 7, 7 godina i pojavnost je bila nešto češća kod muških životinja (58,44%). Obzirom na stupanj malignosti najzastupljeniji je bio drugi, zatim treći i na kraju prvi stupanj. Podatci koji se odnose na spolnu, pasminsku i dobnu predispoziciju i stupanj tumora su bili slični onima u ukupnom broju životinja. Prosječno vrijeme preživljavanja u anketiranoj skupini od 77 životinja je bilo za prvi stupanj 40,5 mjeseci, za drugi 34,4 mjeseci s velikim varijacijama (raspon 1-84 mjeseca) te za treći 22,2 mjeseca. Od 77 pasa, kod 39 su se pojavile ponovo tumorozne tvorbe od kojih je samo 16 potvrđeno kao recidiv patohistološkom ili citološkom dijagnozom. Životinje s mastocitomom drugog i trećeg stupnja s recidivom su imale kraće prosječno vrijeme preživljavanja nego one bez recidiva. Recidiviranje tumora na isto mjesto značajno je skraćivalo preživljavanje u odnosu na recidiv na drugom mjestu. Rezultati rada ukazuju da samo histopatološki stupnjevi mastocitoma određeni po Patnaiku nisu dostatni za prognozu biološkog ponašanja tumora. Najnepredvidljiviji je drugi stupanj što sugerira potrebu primjene dvostupanjske klasifikacije po Kiupelu za smanjenje varijacije u stupnjevanjima. Uz to su potrebne i druge dijagnostičke pretrage poput određivanja proliferacijskih markera.Survival time and disease free interval in dogs with different grade of mast cell tumor In this study, incidence of mastocytoma in dogs and its connection with age, breed, sex, malignacy grade, survival time and disease free interval in five year period (1st of January 2009 - 31st of December 2013.) was investigated. Tumours were analyzed at the Department of veterinary pathology where 133 mastocytoma from 123 dogs were diagnosed. Survival time and disease free interval information was collected for 77 dogs with the help of the owners who participated in a survey. From those 77 dogs, most commonly affected breeds were golden retriver, labrador retriver, german boxer and mongrels. Average age was 7,7 years and male animals were more frequent (58,44%). Regarding the grade of malignacy, most frequent was second grade, then third and in the end first grade. The data for 77 animals that were included in the survey are similar to the data in the entire investigated group (123 dogs). Average survival time for 77 dogs included in the survey was 40,5 months for the dogs with grade I mastocytoma, 34,4 months for grade II (with wide range 1-84 months) and 22,2 months for grade III. Out of 77 dogs, 39 of them had recurrence but only 16 were confirmed as mastocytoma with histopathology or citology. Animals with grade II and III that developed recurrence had shorter average survival time compared to animals without relapse. Animals with local recurrence had a significantly shorter average survival time compared to animals which had recurrence on different location. Our results show that histopathological grading according to Patnaik system alone is not enough for predicting biological behaviour of mastocytoma. Second grade is most unpredictable which suggests the need of using Kiupel's 2-tier histologic grading system which should result in less grading variations. Also, additional diagnostic procedures such as proliferation markers should be implemented