Age at cancer diagnosis by breed, weight, sex, and cancer type in a cohort of more than 3,000 dogs: Determining the optimal age to initiate cancer screening in canine patients

Abstract

The goal of cancer screening is to detect disease at an early stage when treatment may be more effective. Cancer screening in dogs has relied upon annual physical examinations and routine laboratory tests, which are largely inadequate for detecting preclinical disease. With the introduction of non-invasive liquid biopsy cancer detection methods, the discussion is shifting from how to screen dogs for cancer to when to screen dogs for cancer. To address this question, we analyzed data from 3,452 cancer-diagnosed dogs to determine the age at which dogs of certain breeds and weights are typically diagnosed with cancer. In our study population, the median age at cancer diagnosis was 8.8 years, with males diagnosed at younger ages than females, and neutered dogs diagnosed at significantly later ages than intact dogs. Overall, weight was inversely correlated with age at cancer diagnosis, and purebred dogs were diagnosed at significantly younger ages than mixed-breed dogs. For breeds represented by ≥10 dogs, a breed-based median age at diagnosis was calculated. A weight-based linear regression model was developed to predict the median age at diagnosis for breeds represented by ≤10 dogs and for mixed-breed dogs. Our findings, combined with findings from previous studies which established a long duration of the preclinical phase of cancer development in dogs, suggest that it might be reasonable to consider annual cancer screening starting 2 years prior to the median age at cancer diagnosis for dogs of similar breed or weight. This logic would support a general recommendation to start cancer screening for all dogs at the age of 7, and as early as age 4 for breeds with a lower median age at cancer diagnosis, in order to increase the likelihood of early detection and treatment.

Descriptive analysis of haemangiosarcoma occurrence in dogs enrolled in the Golden Retriever lifetime study

“…It is essential that appropriately detailed investigations are used to explore these hypotheses before drawing conclusions. In consideration of other studies of haemangiosarcoma in dogs, a higher median age of diagnosis of visceral haemangiosarcoma was observed in a study with a heterogenous mix of breeds (9.8 years, 19 as compared to 8.7 years in this study), supporting the utility of the genetic data accumulated through this study in exploring breed‐related differential risk.…”

Canine Euthanasia’s Trend Analysis during Thirty Years (1990–2020) in Italy: A Veterinary Hospital as Case Study

“…This could be related to the greater longevity of owned dogs due to the greater attention paid by owners to their animals [19]. However, even though the higher age of dogs euthanized for neoplasia was not statistically significant, the difference is probably "significant" because it may relate to the increased risk of neoplasia at higher ages [20].…”

Study Design and Interim Analysis of the Cancer Lifetime Assessment Screening Study in Canines (CLASSiC): The First Prospective Cancer Screening Study in Dogs Using Next-Generation Sequencing-Based Liquid Biopsy

“…At the time of the interim analysis, a retrospective review of subject demographics was performed in order to determine individual cancer risk at the time of enrollment, based on age, breed, and/or weight. Dogs were considered at increased risk for cancer based on criteria defined by Rafalko et al 18 : any dog 7 years of age or older, dogs at or above the recommended age to start cancer screening based on breed, and dogs at or above the recommended age to start cancer screening based on weight for mixed breeds or uncommon breeds. Based on this review, eighty-four percent (350/419) of subjects were categorized as being at increased risk for cancer.…”