One-Year Conditional Survival of Dogs & Cats with Mammary Carcinomas

In the Literature

Chocteau F, Mordelet V, Dagher E, Loussouarn D, Abadie J, Nguyen F. One-year conditional survival of dogs and cats with invasive mammary carcinomas: a concept inspired from human breast cancer. Vet Comp Oncol. 2021;19(1):140-151.

The Research …

Canine and feline mammary carcinomas exhibit a wide range of clinical behaviors, depending on numerous histologic and clinical factors.^1-7 Veterinary oncologists typically use median survival time after cancer is diagnosed to predict survival rates. Conditional survival, frequently used in human oncology, is the probability of continued survival (measured in months) based on how many months the patient has already survived since the time of diagnosis. This can be further refined based on whether certain criteria are met.

This study sought to describe the one-year overall and cancer-specific conditional survival of female dogs and cats with invasive mammary carcinomas. A secondary goal was to analyze the influence of epidemiologic, clinical, histopathologic, and immunohistochemical parameters on conditional survival.

Records of 344 dogs and 342 cats were retrospectively reviewed for patients with invasive mammary carcinomas treated with surgery alone and with a 2-year follow-up. Dogs that lived at least one year after diagnosis were relatively protected against cancer-related death. The one-year conditional specific survival probability increased from 59% to 80% in this population of dogs. Factors associated with conditional survival in dogs included patient age, nodal stage, cancer stage, lymphovascular invasion, proliferation index, and margin status. 

Feline mammary carcinoma remains a life-threatening condition, even when survival is one year after diagnosis; one-year conditional specific survival probability increased from 48% to 52% in cats.

Conditional survival has been used for a variety of tumors in human medicine, including breast and pancreatic cancer, but has not been investigated in veterinary oncology. Conditional survival is potentially useful for more accurately estimating patient outcomes, especially when identifying prognostic factors in those patients surviving the period in which they are most likely to succumb to disease.

… The Takeaways

Key pearls to put into practice:

• Some dogs diagnosed with mammary carcinomas treated with surgery alone may be relatively protected from cancer-related death if they live at least one year following diagnosis, but this does not appear to be the case for cats.

• The most significant factors associated with increased conditional survival in dogs include patient age, nodal stage, cancer stage, margin status, and lymphovascular invasion.

• Surgical dose and adjuvant chemotherapy were not evaluated in this study but have been important in managing canine and feline mammary carcinomas.