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Mammary gland tumours are common neoplasms that affect female dogs and cats. We compared the accuracy of pre-surgical fine-needle aspiration (FNA) and core needle biopsy (CNB) diagnosing feline (n = 64) and canine (n = 83) mammary gland tumours with excisional histopathology as the gold standard for the definitive diagnosis. We also explored the impact of CNB needle sizes (18G and 16G). FNA, 18G CNB and 16G CNB demonstrated similar accuracy regarding the diagnosis of feline mammary tumours, ranging from 90% to 97.7% (p > 0.05). However, these techniques displayed lower diagnostic accuracy for canine mammary gland tumours: 46.7%-50.9% for FNA, 63.3% for 18G CNB and 73.6% for 16G CNB. In conclusion, FNA and CNB can be used optionally as pre-surgical diagnostic methods for feline and canine mammary gland tumours. However, factors that affect diagnostic accuracy, such as species and diagnostic techniques, should be considered., (© 2024 John Wiley & Sons Ltd.)

The aim of the present study was to retrospectively assess whether spaying at the same time of mastectomy increased disease-free survival (DFS) in bitches with mammary tumours and to investigate the utility of clinical data when designing a surgical plan that includes gonadectomy. Characteristics of 225 bitches carrying 489 tumours were retrieved. Of the116 bitches that underwent surgery, 52 bitches underwent mastectomy and ovariectomy, 46 bitches underwent mastectomy alone, whereas 18 bitches were already spayed. Analysis by Kaplan-Meier and in-between groups comparisons using Student's T, Chi-square, and one-way ANOVA tests were performed. DFS was longer for bitches that underwent ovariectomy and mastectomy compared to those that were left intact (p = .00064) or were already spayed (p = .0098). Spaying status affected tumour size (spayed: 2.75 cm ± 2.72; intact: 1.76 cm ± 2.04; p = .039), but not malignancy (p > .05). Differences in age were detected between animals with benign and malignant tumours (years: 9.1 ± 2.8 and 10 ± 2.3; p = .004), with multiple and single tumours (years: 10.18 ± 2.6 and 9.3 ± 2.8; p = .007), and between purebred and mixed breed bitches (years: 10.46 ±1.78 and 9.27 ±2.68; p = .005). Malignant tumours were larger than benign ones (2.17 cm±2.31 and 1.34 cm ±1.82; p = .005) and size increased according to the degree of malignancy. DFS was shorter for animals presenting tumours >2 cm in size (p < .006) and with tumours in the first pair of thoracic mammary glands (p = .00009). Gonadectomy should be suggested to owners of intact bitches carrying mammary tumours and age, size of the tumour, and location should be carefully considered when performing surgery., (© 2021 John Wiley & Sons Ltd.)

Perioperative administration of desmopressin has shown to significantly decrease rates of local recurrence and metastasis, and increase survival times in dogs with grade II and III mammary carcinomas. The objective of this study was to compare the oncologic outcome of cats with mammary carcinoma treated with bilateral mastectomy with or without perioperative administration of desmopressin. Medical records from nine veterinary institutions were searched to identify cats diagnosed with mammary carcinoma treated with bilateral mastectomy. Sixty cats treated with single-session or staged bilateral mastectomy were included. There were no significant differences in oncologic outcomes found between cats treated and not treated with desmopressin. No adverse effects were seen in any of the cats treated with perioperative desmopressin. Postoperative complications occurred in 18 cats (38.3%) treated with single-session bilateral mastectomy and in three cats (23.1%) treated with staged bilateral mastectomy (P = .48). Histologic grade and a modification of a proposed five-stage histologic staging system were both prognostic for disease-free interval. Incomplete histologic excision was associated with significantly increased rates of metastasis and tumour progression, and a shorter median survival time (MST). Cats that developed local recurrence also had a significantly shorter MST. The results of this study do not support the use of perioperative desmopressin to improve outcome when performing bilateral mastectomy for the treatment of mammary carcinoma in cats., (© 2020 John Wiley & Sons Ltd.)

Optical coherence tomography (OCT) uses near-infrared light waves to generate real-time, high-resolution images on the microscopic scale similar to low power histopathology. Previous studies have demonstrated the use of OCT for real-time surgical margin assessment for human breast cancer. The use of OCT for canine mammary tumours (CMT) could allow intra-operative visualisation of residual tumour at the surgical margins. The purpose of this study was to assess OCT imaging for the detection of incomplete tumour resection following CMT surgery. We hypothesized that the OCT images would have comparable features to histopathological images of tissues at the surgical margins of CMT resections along with a high sensitivity of OCT detection of incomplete surgical excision of CMT. Thirty surgical specimens were obtained from nineteen client-owned dogs undergoing surgical resection of CMT. OCT image appearance and characteristics of adipose tissue, skin, mammary tissue and mammary tumour at the surgical margins were distinct and different. The OCT images of normal and abnormal tissues at the surgical margins were utilized to develop a dataset of OCT images for observer evaluation. The sensitivity and specificity for ex vivo images were 83.3% and 82.0% (observer 1) and 70.0% and 67.9% (observer 2). The sensitivity and specificity for in vivo images were 70.0% and 89.3% (observer 1) and 76.7% and 67.9% (observer 2). These results indicate a potential use of OCT for surgical margin assessment for CMT to optimize surgical intervention and clinical outcomes. Improved training and experience of observers may improve sensitivity and specificity., (© 2020 John Wiley & Sons Ltd.)

This study aims to evaluate the efficacy and side effects of low dose cyclophosphamide chemotherapy plus meloxicam as an adjuvant treatment, compared with high dose doxorubicin or surgery alone in cats with mammary carcinoma. Medical records of 228 female cats treated for mammary carcinoma between 2008 and 2018, were reviewed in eight veterinary institutions. Only cats with complete tumour staging and radical mastectomy were included in the study. One hundred and thirty-seven cats were divided into three treatment groups: group 1 (n = 80) cats treated with surgery, group 2 (n = 34) cats that had surgery and adjuvant treatment with doxorubicin, and group 3 (n = 23) cats with surgery and adjuvant treatment with low dose metronomic cyclophosphamide and meloxicam. The study endpoints were disease free interval (DFI) and overall survival (OS). Toxicity was evaluated according to the VCOG-CTCAE criteria. The median DFI was 270, 226 and 372 days in groups 1, 2 and 3, respectively. The median OS was 338 (group 1), 421 (group 2) and 430 (group 3) days. The differences between groups were not significant (DFI P = .280 and OS P = .186). Toxicity was observed in 52.9% (n = 18) of cats in group 2 and 39.1% (n = 9) of cats in group 3, with mild to moderate intensity. Differences were not significant (P = .306). In conclusion, adjuvant chemotherapy treatment did not improve survival and the overall benefit remains unproven. Randomized prospective trials are necessary to clarify the effectiveness of adjuvant chemotherapy treatment for feline mammary carcinomas., (© 2020 John Wiley & Sons Ltd.)

This retrospective study identified prognostic factors associated with survival; and compared survival data in 94 canine mammary carcinoma (MCA) dogs treated with surgery (n = 58), or surgery and adjunct chemotherapy (n = 36), and a subset of dogs with poor prognostic factors. On multivariate analysis independent predictors of median survival time (MST) were clinical stage, lymphatic invasion (LI; present 179 days; none 1098 days), ulceration (present 118 days; none 443 days) and surgical margins (incomplete 70 days; complete 872 days). Complete surgical margins were associated with MST in dogs with stages 1-3 MCA (incomplete 68 days; complete 1098 days) and dogs with LI (incomplete 70 days; complete 347 days). There was no statistically significant improvement in MST in dogs with advanced disease (stage 4 or LI) treated with adjunctive chemotherapy (chemotherapy 228 days; none 194 days); although five dogs with complete surgical margins that received mitoxantrone and carboplatin had a mean survival of 1139 days., (© 2014 John Wiley & Sons Ltd.)

In this study, we have determined the prognostic value of the presence of the micrometastases and metastases greater than 2 mm in the regional lymph nodes for bitches with mammary carcinomas. The study involved 51 dogs diagnosed with a single malignant epithelial tumour in the 4th or 5th mammary gland. All animals underwent regional mastectomy; the 4th and 5th mammary glands were removed together with the inguinal lymph node. The lymph nodes were examined immunohistochemically using the anti-cytokeratin antibody, clone AE1/AE3. The bitches were followed up every 6 months for 2 years after surgery to determine the disease-free survival (DFS) and overall survival (OS). The Kaplan-Meier analysis showed a statistically significant difference in DFS and OS only between the group of bitches without metastases and the group with lymph node metastases greater than 2 mm. No significant differences between these two groups versus bitches with lymph node micrometastases were found., (© 2011 Blackwell Publishing Ltd.)

Canine mammary tumours are generally treated with surgery alone, despite the fact that 50% of them are malignant and many will eventually lead to recurrence or metastases. A prospective clinical trial in which dogs with aggressive mammary carcinoma of clinical stages IV and V were treated with surgical excision (n = 9) or with surgery and adjuvant weekly gemcitabine (n = 10) for at least four cycles was conducted. Gemcitabine was given as an intravenous infusion at the dose of 800 mg m(-2). Aim of the study was to explore potential beneficial effects of gemcitabine on time to local recurrence (TTR), time to distant metastases (TTM) and overall survival (OS) in canine patients with operated mammary tumours bearing high risk for locoregional failure and distant metastases. Also, factors associated with OS, including neutering status, body weight, age, clinical stage at presentation, tumour size, histological grade and, in dogs receiving chemotherapy, the number of gemcitabine treatments, were investigated. Finally, acute toxicities related to chemotherapy and quality of life were assessed in dogs receiving gemcitabine. Dogs treated with surgery alone or surgery followed by gemcitabine had no difference in TTR, TTM or OS (P > 0.05). In the group of dogs receiving adjuvant chemotherapy, the number of gemcitabine treatments was positively correlated with OS (P = 0.017). Gemcitabine treatment was well tolerated, with no dogs experiencing clinically relevant haematological or gastrointestinal toxicity. Despite being safe at the present dose, gemcitabine chemotherapy as an adjunct treatment to surgical excision may not be recommended in dogs with aggressive mammary carcinoma.