The Italian Network of Laboratories for Veterinary Oncology (NILOV) 2.0: Improving Knowledge on Canine Tumours

Abstract

Advances in tumour research are crucial, and comparative oncology can improve the knowledge in several ways. Dogs are not only models of specific naturally occurring tumours but can also be sentinels of environmental exposures to carcinogens, as they share the same environment with their owners. The purpose of this work was to describe the data collected by The Italian Network of Laboratories for Veterinary Oncology in the first 9 years of activity (2013-2021) and to evaluate their potential epidemiological significance. Frequencies of tumour topographies and main morphologies in dogs were described, analysed and compared, calculating age-adjusted proportional morbidity ratios and considering several risk factors (breed, sex, period and region of residence). These observations allowed us to highlight differences not only in morphology and topography of some tumours but also to formulate hypotheses on the potential role of some risk factors, e.g., neutering/spaying or geographical location. In our opinion, the results of this case series confirm the importance of initiating and consolidating animal cancer registration initiatives that would facilitate the possibility of conducting multicentric collaborative studies to deepen the knowledge of the epidemiology of tumours in dogs from a comparative perspective.

Keywords: animal cancer registry; cancer registry; canine tumours; case series; tumours.

Figure A1

Frequency of benign tumours by sex and topography. (a) Males; (b) females.

Figure A2

Frequency of benign tumours by sex and histotype. (a) Males; (b) females.

Figure A3

Proportional morbidity ratios (PMR) of benign tumour by topography: (a) not neutered males vs. neutered males, (b) not spayed females vs. spayed females. Dots: age-class-adjusted PMR; bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure A4

Proportional morbidity ratios (PMR) of benign tumours by topography comparing purebred and mixed dogs. Dots: age-class-adjusted PMR, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure A5

Proportional morbidity ratios (PMR) of benign tumours by topography comparing benign tumours diagnosed in the last years of activity (2018–2021) with the first period of activity (2013–2017). Dots: age-class-adjusted PMR, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure A6

Proportional morbidity ratios of benign tumours by topography comparing benign tumours diagnosed in Centre (a) and South and Island (b) with Northern Italian regions. Dots: age-class-adjusted PMR, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure A7

Proportional morbidity (PM) (solid lines) and their 95% confidence interval (dotted lines) of visceral benign tumours by period and macroregions.

Figure 1

Distribution of dogs with a diagnosis of tumour by sex, neutered/spayed status and age class at first diagnosis. (a) Males; (b) females.

Figure 2

Choropleth maps showing the number of dogs included in the study. The gradient of colour is proportional to the frequency of observations: the darker the colour, the higher the frequency. (a) Absolute number of dogs with a diagnosis of tumour by macroregion of residency of the owner (North, Centre, South and Islands), (b) number of dogs with a diagnosis of tumour by Italian region, classes follow a quantile distribution, with regions grouped in 5 quintiles, with 4 Regions each. “()“ = excluded; “[]” = included.

Figure 3

Frequency of malignant tumours in dogs by sex and topography; (a) males, (b) females.

Figure 4

Frequency of malignant tumours in dogs by sex and tissue type. (a) Males; (b) females.

Figure 5

Proportional morbidity ratios of malignant tumours by topography: (a) neutered males vs. not neutered males, (b) spayed females vs. not spayed females. Dots: age-class-adjusted PMRs, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1. (a) Males; (b) females.

Figure 6

Proportional morbidity ratios of malignant tumours by topography comparing purebred dogs with mixed dogs. Dots: age-class-adjusted PMRs, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure 7

Proportional morbidity ratios (PMR) of malignant tumours by topography comparing the last years of activity (2018–2021) with the first period of activity (2013–2017). Dots: age-class-adjusted PMRs, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure 8

Proportional morbidity ratios (PMR) of malignant tumours by topography comparing the Italian macro regions ((a,b) North, Centre, South and islands) with the others. Dots: age-clas- adjusted PMRs, bars: lower and upper bound of 95% confidence interval. A vertical reference line indicates PMR = 1.

Figure 9

Proportional morbidity (PM) of external and visceral malignant tumours by macroregions (solid lines) and their 95% confidence interval (dotted lines).