Assessment of prognostic factors in dogs with mammary gland tumors: 60 cases (2014-2020)

Abstract

Canine mammary gland tumors are the most common neoplasms in intact female dogs. Approximately half of all mammary tumors are malignant, and there is a risk of metastasis, which is associated with a poor prognosis. This study is to evaluate the prognostic factors of canine mammary gland tumors and the risk factors associated with the development of malignant tumors. From 2014 to 2020, 60 dogs with mammary gland tumors that underwent surgical treatment were evaluated in this retrospective study. Tumor size, TNM stage, and histopathological results were prognostic factors for 2-year survival after surgery. Every 10 mm increase in tumor size, increased the risk of death within 2 years after surgery 1.213 times. Dogs with TNM stage IV or V had 8.677 fold risk of death within 2 years after surgery. The 2-year survival rate for dogs with benign tumors was 90.2% and for malignant tumors was 67.3%. Tumor size is the most important prognostic factor for canine mammary gland tumors. As tumor size increased by 10 mm, the risk for development of malignant tumors increased by 1.487 times. Tumors larger than 30 mm are highly likely to be malignant, and metastatic evaluation and wide resection should be considered.

Canine mammary carcinoma: current therapeutic targets and future perspectives – a review

“…However, the prognosis of the treatment depends on many factors the age of the dog, tumor stage and size, and neutering status. This is in agreement with the studies by Moon et al (2022) when they analyzed 60 cases of CMC to evaluate the prognosis after the tumor resection. The consensus information creates a new paradigm in the search for or improving the therapeutic modalities of CMC.…”

Risk factor analysis and clinicopathological characteristics of female dogs with mammary tumours from a single-center retrospective study in Poland

“…This can be partially attributed to an infiltrative growth pattern or inflammatory mammary carcinoma without a defined separate palpable mass. We confirmed that the number of tumours had no effect on tumour behaviour, grade, tumour necrosis, tumour ulceration, and prognosis as each tumour may reveal different behaviour and grade 20 , 58 , 60 , 78 .…”

“…The left glands were more often affected, however, this observation should be considered incidental. We showed that the location of malignant CMTs did not affect prognosis 58 , 60 , 81 , 82 ; however, in a recent study, dogs with the affected 1 st gland had a higher recurrence rate 58 .…”

“…The presence of neoplastic emboli, tumour ulceration, and simple or complex carcinoma was demonstrated as independent predictors of local recurrence 21 , 88 . Although old age, large tumour size, grade II or III, and local recurrence were predictive of lung metastases in univariable analysis, only tumour size was retained as an independent prognostic factor 21 , 60 , 82 . This confirms that large malignant CMTs often need a long period of time to acquire metastatic potential 53 .…”

“…In addition, benign tumours and non-neoplastic lesions were smaller compared with malignant tumours 58 , 59 . More recently, other authors noticed that the risk of having a malignant tumour increased approximately 1.5-fold with each 1.0 cm of increase in tumour size, while the risk increased approximately 11.8-fold when the tumour was larger than 5.0 cm compared with smaller tumours (< 3 cm) 60 . Although these data may suggest the previous theory of progression from benign to malignant with increasing tumour size, such an association has never been proven 12 , 59 .…”