Estudo epidemiológico e tempo de sobrevivência de cadelas com tumores mamários de acordo com tratamento cirúrgico

Abstract

Mammary tumor (MT) is the most common neoplasm in female dogs. The standard treatment is tumor excision, and several surgical techniques are available. There is no consensus on which technique is most effective in removing the neoplasm with lower chances of recurrence and longer survival. Previous studies have not identified an association between the mastectomy technique and survival time. The first chapter was a review on the subject. The second chapter aimed to perform an epidemiological analysis of canine MT, describe and associate the clinical-pathological characteristics of female dogs and MT. A retrospective study was carried out using medical records of dogs with MT treated at the Veterinary Hospital of the Federal University of Uberlandia between 2012-2022. The t-test, Wilcoxon and Chi-square tests were used to compare means, medians and associations of variables. The odds ratio was calculated in the significant Chi-square analyses. A total of 724 female dogs and 1638 MT were included. Older, intact, overweight, and purebred bitches were more affected. Malignant tumors were more frequent and were larger than benign ones (3.4 cm and 2.3 cm, CI=95%, p=0.00005). Tumor behavior was associated with age, growth time, tumor quantity, size, and ulceration. Tumor size was associated with growth time, ulceration, adhesion, regional metastases, distant metastases, and histological grade, the latter also being associated with the body condition score. Growth time was also associated with the number of tumors and clinical staging. Bitches with multiple tumors and older bitches were, respectively, 2.6 and 2.1 times more likely to have malignant diagnoses. Older bitches and bitches with distant metastases were, respectively, 1.9 and 1.6 times more likely to have multiple TM. Older female dogs also had a 1.5-fold increased risk of distant metastases. Malignant tumors were 0.3 times more likely to be ulcerated. The third chapter aimed to verify the influence of the type of surgical procedure adopted for the treatment of breast tumors on the survival of female dogs. A total of 351 female dogs and 862 mammary lesions were selected. Age ranged from 1 to 17 years (mean 9.5 ± 7.8 years), and 169 (48.1%) dogs were mixed-breed dogs. Poodles were the most common breed. The majority (59.5%) of the dogs had more than one mammary lesion, and 28.2% had tumors in both mammary chains. Regarding behavior, 88.2% of the tumors were classified as malignant, and carcinoma in mixed tumors was the most frequent malignant neoplasm (31.4%). Unilateral mastectomy was the most frequently performed technique (60.3%), followed by a combination of procedures involving both mammary chains (23.6%). There was no association between the type of mastectomy and the type of mammary carcinoma (p=0.198), between the patient's stage and the surgical technique (p=0.149) and between the patient's stage and age (p=0.084). There was also no difference in the age of the bitches between the groups of each type of mastectomy (p=0.55). The lowest mean survival was for dogs undergoing lumpectomy (179 days) and the highest was regional mastectomy (1654 days), followed by unilateral mastectomy (1639 days).