Phelps-Dunn, A. | Search bioRxiv

bioRxiv2024

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

ObjectiveThe Cancer Lifetime Assessment Screening Study in Canines (CLASSiC) is a prospective, longitudinal cancer screening study, in which enrolled dogs are screened for cancer with physical exams and next-generation sequencing-based liquid biopsy testing on a serial basis. The goals of the first interim analysis, presented here, are to assess the benefits of using the OncoK9(R) liquid biopsy test as a cancer screening tool in a prospective clinical setting, and to demonstrate test performance for cancer detection, including preclinical detection. Subjects726 presumably cancer-free client-owned dogs were prospectively enrolled in the study across 24 clinical sites in the US and Canada. Most subjects were at high risk of cancer at the time of enrollment based on age and/or breed. 419 dogs that were enrolled for at least one year and had at least two cancer screening study visits, or that had received a definitive or presumptive diagnosis of cancer up to the time of the interim analysis, were included in the analysis. MethodsClinical data and a blood sample were collected at each study visit (once or twice per year and when cancer was clinically suspected). Cell-free DNA extracted from plasma was tested by OncoK9(R) using next-generation sequencing (NGS) technology. Results417 dogs were eligible for inclusion in the interim analysis and had classifiable outcomes, with a mean on-study duration of 422 days. Of these, 51 dogs were newly diagnosed with cancer (37 definitive, 14 presumptive), translating to a 12% (51/417) observed incidence over the study period; the liver, skin, bone, heart, spleen, lung, and lymph node(s) were the most common anatomic locations for disease. The prospectively observed sensitivity (detection rate) of the test was 56.9% (95% CI: 42.3-70.4%) with a specificity of 98.9% (95% CI: 97.0-99.6%). The prospectively observed positive predictive value was 87.9% (95% CI: 70.9-96.0%) and the negative predictive value was 94.3% (95% CI: 91.3-96.3%). NGS-based liquid biopsy doubled the overall number of cancer cases detected in this study population (from 25 to 51); remarkably, the detection rate for preclinical cancer was increased 4.6-fold from 12% (6/51) by routine care alone to 55% (28/51) by combining routine care with OncoK9(R) testing. Clinical RelevanceCLASSiC is the [fi]rst study to prospectively document the incidence of cancer in a predominantly high-risk canine population, and to prospectively demonstrate that the addition of NGS-based cancer screening to regularly scheduled wellness visits has the potential to substantially increase preclinical cancer detection in this population.

genomics↗

bioRxiv2022

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

The goal of cancer screening is to detect disease at an early stage when treatment may be more effective. Until recently, 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, data from 3,452 cancer-diagnosed subjects were analyzed to determine the age at which dogs of certain breeds and weights are typically diagnosed with cancer. In the study population, the median age at cancer diagnosis was 8.8 years, with males diagnosed at younger ages than females, and spayed/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 with 10 or more subjects, 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 fewer than 10 subjects and for mixed-breed dogs. The study findings support a general recommendation to start cancer screening for all dogs at the age of 7, and as early as 4 years of age for breeds with a lower median age at cancer diagnosis, in order to increase the chances of early detection and treatment.

cancer biology↗