Using Raman Spectroscopy for Analysis of Canine Urinalysis

A new research collaboration shows how Raman spectroscopy can be used to improve cancer detection in dogs, according to a new study published in Frontiers in Veterinary Science (1). The new method introduced in this study involves using Raman spectroscopy to analyze dog urine screening tests to detect spectral fingerprints in urine that could indicate the presence of cancer.

Common cancers in dogs include lymphoma, osteosarcoma, soft tissue sarcomas, and melanoma, and fibrosarcoma, among others (2). To detect cancer in dogs, some of those screening methods include liquid biopsies and urinalysis (3–5). Liquid biopsy is a medical screening test that examines blood, urine, or other body fluids for evidence of disease markers (4). Urinalysis, as its name suggests, tests specifically urine. For dogs, a urinalysis is conducted to test for urinary tract infections (UTIs), which are common for dogs, as well as kidney problems or diabetes (6). Because urinalysis tests are often used in veterinary medicine, scientists have dedicated significant time to identify possible ways to improve test accuracy, which can improve patient diagnosis.

Australian shepherd dog outside in beautiful colorful autumn. | Image Credit: © Evelina - stock.adobe.com

A collaborative research effort involving scientists from Virginia Tech, Rametrix Technologies Inc., Wake Forest University, and VCU Health, explored this issue. Previously reporting on Rametrix technology, which is a Raman spectroscopy-based technology, the objective of this study was to interpret the results of Raman analysis of urine specimens from 89 healthy dogs, 100 dogs diagnosed with cancer, and 16 dogs with non-neoplastics urinary tract or renal diseases (1).

The urine samples were obtained through voiding, cystocentesis, or catheterization. The research team then employed Raman spectroscopy to analyze these samples, creating a multimolecular spectral fingerprint that revealed hundreds of features related to the urine's chemical composition (1).

Using the Rametrix Toolbox software, the research team used principal component analysis (PCA) and discriminant analysis of principal components (DAPC), along with ISREA (a peak-preserving baseline correction algorithm for Raman spectra), to analyze the spectroscopic data (1). By using this approach, the researchers were able todetect the broad presence of cancer in canine urine, as well as identify specific types of cancer, including lymphoma, urothelial carcinoma, osteosarcoma, and mast cell tumors (1).

A deep dive into the accuracy rates shows how promising the method used truly is. One of the first tests the researchers looked at was whether their method could differentiate between cancer-free and cancerous dogs. Their study showed that their method achieved a 92.7% accuracy rate in distinguishing between cancerous and cancer-free dogs (1). The test demonstrated a sensitivity of 94.0%, specificity of 90.5%, positive predictive value (PPV) of 94.5%, and negative predictive value (NPV) of 89.6% (1).

The Raman bands responsible for discerning cancer were extracted from the analysis, and biomolecular associations were obtained (1). This non-invasive, rapid urine screen is particularly effective in distinguishing urothelial carcinoma from other types of cancer. The ability to detect and classify cancer in dogs using a simple urine test, as opposed to more invasive methods like liquid biopsies, represents a critical advancement in veterinary cancer care (1).

Because the assay uses Raman spectroscopy to discern spectral fingerprints, this method is suitable for wellness evaluations, aiding in the early detection of cancer, especially in breeds predisposed to certain types of cancer (1). The researchers also noted that their method could be useful in monitoring responses to therapy and evaluating the recurrence or progression of tumors (1).

Future research in using Raman spectroscopy in urinalysis, the researchers said, should expand to test dogs of all ages and breeds, diversifying the sample set by incorporating subjects who suffer from other diseases (1).

References

(1) Robertson, J. L.; Dervisis, N.; Rossmeisl, J.; et al. Cancer Detection in Dogs Using Rapid Raman Molecular Urinalysis. Front. Vet. Sci. 2024, 11, 1328058. DOI: 10.3389/fvets.2024.1328058

(2) UW Veterinary Care, Common Types of Cancer in Dogs. University of Wisconsin–Madison. Available at: https://uwveterinarycare.wisc.edu/common-types-of-cancer-in-dogs/ (accessed 2024-07-24).

(3) Nolen, R. S. Genomic Tests Show Promise for Early Detection of Canine Cancers. AVMA.org. Available at: https://www.avma.org/news/genomic-tests-show-promise-early-detection-canine-cancers#:~:text=One%20of%20the%20latest%20veterinary,it%20may%20be%20more%20treatable. (accessed 2024-07-24).

(4) Intile, J.; Gareau, A. Liquid Biopsy: The Future of Cancer Detection in Dogs? Today’s Veterinary Practice. Available at: https://todaysveterinarypractice.com/oncology/liquid-biopsy-in-veterinary-medicine/ (accessed 2024-07-24).

(5) Maeda, M. New Canine Cancer Screening Tests. Canine Cancer Alliance. Available at: https://www.ccralliance.org/post/cancer-screening-tests-webinar-june-13-2024#:~:text=Oncotect%20is%20a%20urine%2Dbased,VOCs%20emitted%20by%20cancer%20cells. (accessed 2024-07-24).

(6) MedlinePlus, Urialysis. MedlinePlus.gov. Available at: https://medlineplus.gov/urinalysis.html#:~:text=A%20urinalysis%20is%20a%20test,some%20medical%20conditions%20and%20treatments. (accessed 2024-07-24).