Comparative epidemiological study of breast cancer in humans and canine mammary tumors: insights from Portugal

Paulo Tiago Carvalho; João Niza-Ribeiro; Irina Amorim; Felisbina Queiroga; Milton Severo; Ana Isabel Ribeiro; Katia Pinello

doi:10.3389/fvets.2023.1271097

Comparative epidemiological study of breast cancer in humans and canine mammary tumors: insights from Portugal

Front Vet Sci. 2023 Nov 30:10:1271097. doi: 10.3389/fvets.2023.1271097. eCollection 2023.

Authors

Paulo Tiago Carvalho¹, João Niza-Ribeiro^{1

2

3}, Irina Amorim⁴, Felisbina Queiroga^{5

6

7}, Milton Severo^{2

3}, Ana Isabel Ribeiro^{2

3

8}, Katia Pinello^{1

2

3}

Affiliations

¹ Vet-OncoNet, Population Studies Department, School of Medicine and Biomedical Sciences, ICBAS, University of Porto, Porto, Portugal.
² Epidemiology Unit (EPIUnit), Institute of Public Health of the University of Porto (ISPUP), Porto, Portugal.
³ Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal.
⁴ Department of Pathology and Molecular Immunology, School of Medicine and Biomedical Sciences ICBAS, University of Porto, Porto, Portugal.
⁵ Department of Veterinary Sciences, University Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.
⁶ Centre for Animal and Veterinary Science (CECAV), University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
⁷ Center for Animal Science Studies, Institute of Sciences, Technologies and Agroenvironment (CECA-ICETA), University of Porto, Porto, Portugal.
⁸ Department of Public Health and Forensic Sciences and Medical Education, Faculty of Medicine, University of Porto, Porto, Portugal.

Abstract

Dogs spontaneously develop mammary gland tumors (MGT) and exhibit striking similarities in clinical and epidemiological characteristics to human breast cancer (HBC). Descriptive and comparative analysis of HBC and canine MGT with a focus on evaluating similarities and geographical distribution were the aims of this study. HBC cases were obtained from North Regional Oncological Registry (RORENO) (2010-2015) and canine MGT cases from Vet-OncoNet (2019-2022). Analyses were performed based on published and well accepted classification systems (ICD-O-3.2 for humans and Vet-ICD-O-canine-1). Age-standardized incidence risks (ASIR) of Porto district municipalities were calculated using 2021 Portuguese census (INE) and data from the Portuguese animal registration system (SIAC). Among 7,674 HBC cases and 1,140 MGT cases, a similar age and sex distribution pattern was observed. Approximately 69.2% of HBC cases were between 40 and 69 years old, while 66.9% of MGT cases were diagnosed between 7 and 12 years old (mean age of 9.6 years, SD = 2.6). In women, Invasive breast carcinoma (8500/3) was the most common histological type (n = 5,679, 74%) while in dogs it was the Complex Carcinoma (8983.1/3) (n = 205, 39%). Cocker and Yorkshire Terriers exhibited the highest relative risks (3.2 and 1.6, p < 0.05, respectively) when compared to cross breed dogs. The municipalities' ASIR of the two species exhibited a high correlation (R = 0.85, p < 0.01) and the spatial cluster analysis revealed similar geographic hotspots. Also, higher ASIR values both in women and dogs were more frequently found in urbanized areas compared to rural areas. This research sheds light on the shared features and geographical correlation between HBC and canine MGT, highlighting the potential of cross-species environmental oncology studies.

Keywords: LISA cluster analysis; breast cancer; canine; cluster analysis; comparative oncology; environmental; geographic; mammary gland tumor.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was financed through the financial support of the School of Medicine and Biomedical Sciences, ICBAS, University of Porto. Ana Isabel Ribeiro was supported by National Funds through FCT, under the Stimulus of Scientific Employment—Individual Support programme within the contract CEECIND/02386/2018.