Evaluation of the reliability of the use of infrared thermography in the categorization of tumors in dogs

Infrared thermography (IRT) has been explored as a complementary diagnostic tool in dogs, particularly in oncology. However, few studies have assessed its applicability to non-neoplastic skin tumors or compared thermal patterns between malignant and benign tumors. This study evaluated IRT as a method for distinguishing thermal patterns between healthy skin and cutaneous tumoral lesions in dogs. A total of 103 skin lesions from 57 dogs, either male or female, of different breeds, and average age of 10 years, were analyzed and classified into benign neoplasms, malignant neoplasms, and non-neoplastic tumors. Mean surface temperatures were obtained for three areas: tumoral (El1), transitional (LiM), and healthy adjacent skin (El2). Rectal temperature was also assessed using a digital thermometer. Results showed that, in the malignant neoplasm group, the temperature of El1 was significantly lower when compared to both El2 and LiM within the same group (p= 0.008). Additionally, El1 exhibited slightly higher average temperatures (0.5‐0.6 °C) in the malignant neoplasm (33.2 ± 2.4 °C) and non-neoplastic group (33.5 ± 1.5 °C) compared to benign neoplasms (32.6 ± 2.5 °C), although this difference was not statistically significant (p=0.301). In conclusion, IRT is a promising tool for differentiating thermal emissions between skin tumors/lesions and healthy skin in dogs. Healthy areas were significantly warmer than affected tissue. Malignant neoplasms and non-neoplastic lesions showed higher thermal means in the tumoral area compared to benign neoplasms.