Spanish-Speaking Veterinarians Now Have a Validated Tool to Assess Quality of Life in Dogs with Cancer
New research provides the first culturally adapted quality-of-life questionnaire for canine oncology patients in Spanish-speaking populations
For veterinarians treating dogs with cancer in Spanish-speaking countries, assessing quality of life has long presented a challenge: while multiple assessment tools exist in English, none had been properly validated for Spanish-speaking populations. A new study published recently changes that, providing the first rigorously validated Spanish version of the Canine Owner-Reported Quality of Life (CORQ) questionnaire.
Led by Carmen Pérez and colleagues at the Complutense University of Madrid, the research team followed World Health Organization guidelines to translate, culturally adapt, and validate this essential clinical tool—filling a significant gap in veterinary oncology care.
Why This Matters for Practice
Quality of life assessment has become increasingly important in veterinary oncology, yet many practitioners have relied on non-validated scales or informal assessments. Without validated tools in their own language, Spanish-speaking veterinarians lacked reliable, standardized instruments to guide treatment decisions and monitor disease progression.
"Simple translation isn't enough," the researchers emphasize. Cultural adaptation ensures that the tool captures the nuances of how Spanish-speaking pet owners perceive and report their dogs' well-being, rather than introducing biases that could affect validity.
The Original CORQ
Developed by Giuffrida and colleagues in 2018, the CORQ assesses owner-reported observations of their dogs' quality of life through 17 items covering vitality, behavior, pain, and mobility. Owners rate how frequently certain behaviors occur on a 0-7 scale, with higher scores indicating better quality of life.
The tool focuses on observable behaviors that owners can reliably monitor—things like appetite, sleep patterns, energy levels, and social interaction—rather than requiring owners to make complex judgments about abstract concepts.
A Rigorous Six-Phase Process
The Spanish adaptation wasn't a quick translation job. The research team followed a comprehensive six-phase protocol:
Phase 1-2: Translation and Reconciliation Two independent bilingual translators—one veterinarian and one non-specialist—created separate Spanish versions. A panel of five veterinary experts then reviewed and merged these translations, resolving discrepancies and ensuring technical accuracy while maintaining accessibility for non-specialist pet owners.
Phase 3-4: Back-Translation and Author Review A native English speaker unfamiliar with the original questionnaire translated the Spanish version back to English. The research team and original author then compared this back-translation with the original, identifying and resolving any conceptual mismatches.
For example, the item "My dog slept well at night" was refined from "all night" to "during the night" to accommodate typical canine sleep patterns. The item about food consumption was clarified to distinguish between appetite (general interest in eating) versus preference for usual food (some dogs avoid regular meals but still eat treats).
Phase 5: Cognitive Interviews Eighty-five Spanish-speaking dog owners whose pets had various tumor types completed the questionnaire and provided feedback on clarity and comprehension. The group was diverse in age, gender, and educational background—from those with no formal education to those with advanced degrees.
The results were encouraging: 63.5% rated the questionnaire as "very easy" to understand, 29.4% found it "easy," and only 7.1% rated it "neither easy nor difficult." Notably, no participants selected "difficult" or "very difficult."
Phase 6: Final Linguistic Review A philologist conducted a final linguistic check to ensure cultural and grammatical accuracy, confirming the Spanish CORQ was written in clear, everyday language accessible to the target audience.
Strong Validation Results
The psychometric evaluation confirmed the Spanish CORQ is a reliable tool:
High internal consistency: Cronbach's alpha of 0.946 for wellness and 0.841 for vitality
Strong correlations: Significant associations with established quality-of-life measures
Clear factor structure: Items loaded appropriately on their intended constructs
Interestingly, the Spanish version revealed a two-factor structure (wellness and vitality) rather than the original four-factor model (vitality, companionship, pain, and mobility). However, specific items showed similar patterns to the original, suggesting the core concepts remain intact despite the different structural organization.
Clinical Applications
The validated Spanish CORQ gives practitioners a standardized way to:
Monitor disease progression objectively over time
Guide treatment decisions based on quantifiable quality-of-life data
Facilitate owner communication through structured conversations about observable behaviors
Document outcomes for medical records and research
Determine appropriate timing for difficult end-of-life decisions
The questionnaire takes approximately 10 minutes to complete, making it practical for routine clinical use. Owners reflect on their dog's behavior over the previous seven days, providing a meaningful snapshot of quality of life between visits.
Study Population
The validation study included dogs with various tumor types:
Mammary tumors (24.7%)
Soft tissue sarcoma (16.5%)
Cutaneous mast cell tumors (10.6%)
Multicentric lymphoma (8.2%)
Various other tumor types
The canine participants had a mean age of nearly 10 years, and most were neutered—a demographic profile representative of many oncology practices.
Limitations and Future Directions
The researchers acknowledge several limitations. The sample size of 85, while adequate for initial validation, is relatively modest. Future studies with larger, more diverse populations would strengthen confidence in the tool's generalizability.
The study also didn't assess test-retest reliability—the stability of results when the same dog is assessed at different times under similar conditions. While the original CORQ showed good test-retest reliability, confirming this in the Spanish version would be valuable.
Additionally, like all owner-reported measures, the CORQ is subjective and may be influenced by owners' emotional states and perceptions. This isn't necessarily a flaw—owners know their dogs best—but it's an inherent characteristic of the methodology that practitioners should keep in mind.
The Bottom Line
Spanish-speaking veterinarians now have access to a rigorously validated, culturally appropriate tool for assessing quality of life in their canine cancer patients. The Spanish CORQ maintains the strengths of the original while ensuring conceptual and linguistic equivalence for Spanish-speaking populations.
For practitioners, this means more confidence in quality-of-life assessments, better documentation, and improved communication with clients about their dogs' well-being during cancer treatment. It's a practical tool that addresses a real clinical need, backed by solid psychometric validation.
The research team has made both the final Spanish CORQ and the cognitive-debriefing materials available as supplementary materials, facilitating adoption in clinical practice.
The study, "Cultural adaptation and psychometric properties of the canine owner-reported quality of life questionnaire (CORQ) for assessing quality of life in dogs with cancer," was led by Carmen Pérez and colleagues from the Complutense University of Madrid, in collaboration with original CORQ developer Michelle A. Giuffrida.
