Frequency and Risk Factors
Mammary tumors account for approximately one-third of tumors diagnosed in cats. They mainly affect females that were never spayed or spayed later in life, with a peak incidence around 10 years of age. Young animals and males are rarely affected.
Risk factors include:
- Increased risk in fertile female cats; early sterilization significantly reduces the likelihood of developing these tumors.
- Previous use of hormonal treatments to suppress heat cycles increases the risk due to pathological cellular changes.
- Unfortunately, more than 80% of mammary tumors in cats are malignant at diagnosis.
Clinical Signs
Physical examination can reveal several abnormalities, such as:
- Firm and nodular masses: More than 50% of cases involve multiple mammary glands.
- Variable locations: Tumors can develop along the entire mammary chain.
- Variable sizes: Tumors range from a few millimeters to several centimeters.
- Tissue fixation: Some masses adhere to deeper tissues, making them immobile.
- Skin ulceration: Observed in approximately 25% of cases.
- Abnormal secretions: Possible from affected nipples.
- Enlarged lymph nodes: Often axillary or inguinal.
- Cachexia: Seen in advanced stages of the disease.
The remainder of the clinical examination typically appears normal.
Diagnosis of Mammary Tumors
An excisional biopsy is the method of choice to confirm a diagnosis. This surgical procedure removes the tumor for subsequent laboratory analysis.
Alternatives include:
- Fine needle aspiration cytology: Often yields inconclusive results. It involves the microscopic analysis of collected tumor cells.
- Chest radiographs: Recommended before surgery to detect possible pulmonary metastases, as malignant tumors frequently spread to the lungs.
Treatment Options
Surgical removal of tumor tissues is the primary treatment method. Techniques vary based on the severity and extent of the tumors:
- Local excision: Removes isolated tumor nodules.
- Simple mastectomy: Removes a single affected mammary gland.
- Radical mastectomy: Removes multiple affected mammary glands.
Sterilization may be performed simultaneously in fertile cats, though studies have not shown significant survival advantages associated with this procedure at the time of mastectomy.
Prognosis and Follow-Up
Post-surgical outcomes depend on several factors, including:
- Mammary adenocarcinoma: The most common malignant tumor type.
- Invasion into blood and lymphatic vessels: Indicates a poorer prognosis.
- Cell differentiation: Poorly differentiated cells correlate with aggressive disease progression.
- Tumor size: Prognosis improves when tumors are smaller than 2 cm.
Post-surgery, chemotherapy may be recommended to prolong survival and reduce recurrence risk.
Early detection and timely management significantly improve the prognosis for cats affected by mammary tumors.
