Evaluation of Adjuvant Doxorubicin‐Based Chemotherapy for the Treatment of Feline Mammary Carcinoma

Abstract

Background: Feline mammary carcinomas (FMC) are locally invasive and highly metastatic tumors. Because of the high metastatic potential, patients often are treated with adjuvant doxorubicin-based chemotherapy, but little data exist to evaluate the effect of this strategy.Hypothesis: Adjuvant doxorubicin-based chemotherapy improves outcome for FMC compared with surgery alone. Animals: Cats with naturally occurring, biopsy-confirmed FMC treated with either surgery alone (Sx) or with surgery plus adjuvant doxorubicin-based chemotherapy (Sx 1 Chemo).Methods: Retrospective cohort study. Clinical data were collected and compared to identify differences between groups. Outcome results were determined and compared. Prognostic factors for disease-free survival (DFS) and overall survival were evaluated.Results: Seventy-three cats were evaluated, of which 37 were in the Sx group and 36 in the Sx 1 Chemo group. No differences in clinical data were found between Sx and Sx 1 Chemo groups. Median DFS times for the Sx and Sx 1 Chemo groups were 372 and 676 days, respectively (P 5 .15) and median survival times (ST) were 1,406 and 848 days, respectively (P 5 .78). For cats that underwent a unilateral radical mastectomy, ST was significantly longer for the Sx 1 Chemo compared with the Sx group (1,998 versus 414 days, respectively; P 5 .03).Conclusions and Clinical Importance: This study did not find a benefit to adjuvant doxorubicin-based chemotherapy in cats with FMC. Additional studies are required to determine whether patient subgroups with negative prognostic factors may benefit from adjuvant chemotherapy.

Factors Which Influence Owners When Deciding to Use Chemotherapy in Terminally Ill Pets

“…Similar results have been found in cats that have undergone chemotherapy for extranodal lymphoma recording survival times ranging from 70 days to 749 days [25]. Surgical removal of malignant neoplastic masses without an accompanying chemotherapy course can also exert a beneficial impact on survival, however survival time is often reduced compared to animals with the same diagnosis who undergo surgery and chemotherapy (mammary carcinoma) [26]. Therefore, chemotherapy is considered to extend survival time for the terminally ill pet compared to surgical reduction alone and has a clear benefit as part of an oncology treatment regime [27].…”

TiHo-0906: a new feline mammary cancer cell line with molecular, morphological, and immunocytological characteristics of epithelial to mesenchymal transition

“…84 . The cat was admitted to the Small Animal Clinic at the University of Veterinary Medicine Hannover and underwent unilateral chain mastectomy.…”

Reproductive System

“…In these cases, samples should be submitted for histopathologic examination to rule out the presence of a malignancy. In contrast, a cohort study did not find benefit of adjuvant doxorubricin-based chemotherapy (McNeill et al, 2009). If a malignancy is present, staging the extent of the disease should include three-view thoracic radiographs or CT scan of the lungs and any other potential metastatic sites as well as cytologic analysis of regional lymph nodes, suspected metastatic lesions, and/or body cavity effusions.…”