고양이 유선 종양 자주 묻는 질문 Q&A — 보호자가 꼭 알아야 할 핵심

What Are Feline Mammary Tumors? — Key Q&A on Symptoms, Malignancy, and Treatment

Q: Can feline mammary tumors be treated?

Yes, with early detection, surgery can lead to a favorable outcome. The treatment approach and prognosis depend on the tumor’s size and whether it has metastasized.

Q: What happens if surgery is not performed?

If surgery is not performed, the tumor is likely to grow and spread. Larger, more advanced tumors tend to shorten life expectancy.

Q: How often does the condition recur after surgery?

The likelihood of recurrence depends on the tumor’s size, malignancy, and the extent of surgical removal. Early and complete excision leads to a better prognosis, but regular check-ups are essential.

Q: Are feline mammary tumors hereditary?

The development of mammary tumors is significantly influenced by age and hormonal status, particularly whether the cat has been spayed. There is insufficient evidence to definitively identify a clear genetic cause, and these tumors are more common in intact females and cats in middle age or older.

Q: How can I prevent it?

Neutering is known to be beneficial. Unneutered cats are reported to have a higher risk of developing the condition compared to neutered cats, but it is difficult to definitively state specific figures such as a 90% reduction in risk when neutered before six months of age.

Oncology/CancerQ&AMeongsiljang Veterinary Advisory Board

Feline mammary tumors are among the most common malignant cancers in cats. Early detection and appropriate treatment can significantly improve survival rates. Here’s a summary of the essential information every pet owner should know.

What Are Feline Mammary Tumors?

Feline mammary tumors are masses that develop in the mammary tissue, and unlike in dogs, the majority are malignant. While statistics vary by study, approximately 80–96% of mammary masses in cats are confirmed to be malignant. The risk of development is higher in intact cats, and hormonal influences are known to be associated with mammary cell proliferation. - Malignant tumors: Malignant tumors can grow and metastasize to other areas, such as lymph nodes or the lungs, making early detection crucial. - Benign tumors: Benign tumors (e.g., fibroadenomas) can also occur, but they are difficult to distinguish from malignant ones based on appearance alone, so accurate diagnosis is essential. - Risk factors: Age, sex (primarily females), and spaying status are the main risk factors. - Early treatment: Prognosis is better when tumors are detected and treated while still small. Tumor size is closely linked to prognosis, so early detection has a decisive impact on outcomes.

Why Are Feline Mammary Tumors Common?

The risk of mammary tumors in cats increases with age. The average age at diagnosis is approximately 10 to 12 years, meaning they primarily affect middle-aged and older cats. This is linked to the continuous action of sex hormones on the mammary glands in intact (unspayed) cats. - Spay Status: Intact cats have a higher risk of developing mammary tumors compared to spayed cats (studies report a relative risk of about 3.4 times higher). - Hormonal Influence: Sex hormones such as estrogen and progesterone (particularly progestins) are known to stimulate the proliferation of mammary epithelial and stromal cells. - Age Factor: The risk increases as cats enter middle age and beyond, with an average diagnostic age of 10 to 12 years. - Preventive Effect: Spaying helps reduce the risk of mammary tumors. However, the exact degree of risk reduction varies depending on the timing and individual cat, making it difficult to specify a precise figure.

A veterinarian gently palpating a cat’s mammary glands during an examination.

What Are the Main Symptoms?

The main symptoms of feline mammary tumors include lumps in the mammary glands, skin redness, bleeding, pus discharge, and pain. As the tumor grows, it may limit movement or reduce appetite. - Lump Detection: When touching the mammary area, you may feel hard or clumped masses. - Skin Changes: The skin may become red, flaky, or even bleed. - Behavioral Changes: If the cat experiences pain, it may cry out or avoid being touched. - Signs of Metastasis: If the tumor grows rapidly or spreads to other areas, lethargy and weight loss may occur. Early detection significantly improves survival rates.

Actual image of a tumor on a cat's mammary gland

Signs Requiring Immediate Veterinary Visit

If you notice a lump growing rapidly in the mammary glands, bleeding, signs of pain such as crying or avoidance, or decreased appetite and lethargy, please visit a veterinarian immediately. Early treatment improves survival rates.

How Is Diagnosis Performed?

Diagnosis involves palpating the mammary lesions to assess them directly, followed by fine-needle aspiration (FNA) cytology or biopsy to determine the nature of the tumor and whether it is malignant. Additional tests are also performed for staging. - Cytology and Histopathology: Fine-needle aspiration cytology evaluates the tumor cells, while biopsy collects tissue samples for definitive pathological diagnosis. - Lymph Node Assessment: Aspiration of regional lymph nodes is recommended to check for metastasis. - Thoracic Radiographs: Chest X-rays are recommended to detect potential metastasis to the lungs or other thoracic structures. - Blood Work: Blood tests assess the pet’s overall health to evaluate suitability for anesthesia and treatment. - Imaging Studies: In complex cases, additional imaging such as ultrasound or CT scans may be utilized. Accurate diagnosis and staging form the foundation for developing a treatment plan.

Ultrasound examination of a cat's mammary glands

What Are the Treatment Options?

Treatment depends on the tumor’s size and degree of malignancy. In most cases, surgery is the first step. After surgery, radiation therapy or chemotherapy may also be needed. - Surgical treatment: The basic approach is to remove the tumor along with the surrounding mammary tissue. Depending on the case, unilateral or bilateral mastectomy may be performed. - Radiation therapy: This may be considered alongside surgery if the lesion is large or invasive. - Chemotherapy: In cases of high-grade malignancy or advanced stages, there are reports of using carboplatin in combination with surgery. - Treatment plan: A personalized treatment plan is developed based on the tumor’s size and stage. - Prognosis: Prognosis is largely determined by tumor size and whether metastasis has occurred. One study reported a median survival time of approximately 6 months for tumors larger than 3 cm in diameter, and about 2 years for those between 2 and 3 cm. The earlier the diagnosis and treatment, the better the outcome.

Comparison of Management Strategies by Treatment Stage

Item	Main treatment	Prognosis (median survival time)	Precautions
Early stage (tumor < 2 cm, stage I)	Complete surgical resection	The smaller the tumor, the better the prognosis	Regular check-ups required after surgery
Intermediate stage (2–3 cm, stage II)	Surgery ± radiation/chemotherapy	Median survival time about 2 years	Need to check for metastasis
Advanced stage (over 3 cm or metastasis, stage III–IV)	Surgery + chemotherapy, palliative care	Median survival time about 6 months	Pain and metastasis management essential

Survival time varies depending on tumor size and presence of metastasis. In one study, a median survival time of about 6 months was reported for tumors larger than 3 cm, and about 2 years for tumors 2–3 cm. Early surgery is the most effective.

Pre- and Post-Operative Precautions

After surgery, it’s important to keep the wound clean to prevent infection. Restrict your cat’s activity to minimize movement, and pain management may be necessary. Be sure to follow up with medication and a recheck visit within two weeks after the procedure.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can feline mammary tumors be treated?

Yes, with early detection, surgery can lead to a favorable outcome. The treatment approach and prognosis depend on the tumor’s size and whether it has metastasized.

What happens if surgery is not performed?

If surgery is not performed, the tumor is likely to grow and spread. Larger, more advanced tumors tend to shorten life expectancy.

How often does the condition recur after surgery?

The likelihood of recurrence depends on the tumor’s size, malignancy, and the extent of surgical removal. Early and complete excision leads to a better prognosis, but regular check-ups are essential.

Are feline mammary tumors hereditary?

The development of mammary tumors is significantly influenced by age and hormonal status, particularly whether the cat has been spayed. There is insufficient evidence to definitively identify a clear genetic cause, and these tumors are more common in intact females and cats in middle age or older.

How can I prevent it?

Neutering is known to be beneficial. Unneutered cats are reported to have a higher risk of developing the condition compared to neutered cats, but it is difficult to definitively state specific figures such as a 90% reduction in risk when neutered before six months of age.

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References

[1] Hahn, K.A., G.K. King, and J.K. Carreras. 2004. Efficacy of radiation therapy for incompletely resected grade-III mast cell tumors in dogs: 31 cases (1987–1998). J Am Vet Med Assoc 224:79–82.

[2] Théon, A.P., B.R. Madewell, V.I. Shern, et al. 1995. Prognostic factors associated with radiotherapy of squamous cell carcinoma of the nasal plane in cats. J Am Vet Med Assoc 206(7):991–996.

[3] Dees DD, Schobert CS, Dubielzig RR, Stein TJ. Third eyelid gland neoplasms of dogs and cats: a retrospective histopathologic study of 145 cases. Vet Ophthalmol. 2016;19(2):138–143.