Mastectomy — removal of mammary glands affected by a tumour

What it involves

Mastectomy is the removal of a mammary gland tumour or tumours together with the surrounding tissue and, if necessary, the whole chain of mammary glands on one side (regional or unilateral mastectomy). We match the extent of the excision to the number, size and position of the lesions — we do not remove more than necessary, but no less than the oncological margin requires either.

In bitches about half of mammary tumours are malignant; in female cats, the great majority. Appearance or touch alone cannot tell a benign tumour from a malignant one — the answer comes only from histopathological examination of the removed tissue. That is why we send every tumour we remove for assessment and discuss the result with the owner.

We carry out the operation under general anaesthesia with full monitoring, using an electrocautery unit, which limits bleeding in the richly vascularised glandular tissue. If the bitch is not spayed, we often combine mastectomy with spaying under one anaesthetic.

When it is used

When a lump can be felt in the mammary gland — regardless of its size. Small, single lesions have the best prognosis, so we do not recommend “keeping an eye on” them until they grow.

Before the procedure we carry out staging: chest X-ray in three views and abdominal ultrasound. If the images point to metastases, we discuss the treatment plan together with the owner during an oncology consultation.

Indications: symptoms that should prompt a visit

• You can feel a hard lump beside a nipple in your dog or cat that was not there before.
• The lump is growing over weeks, or further ones have appeared.
• The skin over the lesion is red or ulcerated, or the tumour is bleeding.
• Fluid leaks from a nipple outside lactation.
• The dog or cat licks the area around the nipples and does not allow it to be touched.
• An unspayed bitch after many heats or false pregnancies — the highest-risk group.

Conditions for which we use it in particular

Diagnostics beforehand

We begin with a clinical examination and careful palpation of all the mammary glands and of the axillary and inguinal lymph nodes. A chest X-ray in three views rules out or confirms metastases to the lungs — without this image we do not consider a patient suitable for oncological surgery. Abdominal ultrasound assesses the lymph nodes, liver and spleen.

In selected cases we perform a fine-needle biopsy and cytology of the lesion or lymph node on site. A blood test and pre-anaesthetic assessment according to standard STD-01 are mandatory; many patients are seniors, so we often add a cardiac examination.

How it proceeds

Aftercare

At home: a body suit or collar for 14 days, restricted movement, painkillers and possibly an antibiotic according to the schedule. The wound after a mastectomy is long, and swelling or slight discharge may appear on it — wound check after 2–3 days, we remove sutures after 10 days.

We discuss the histopathology result at a separate visit: it determines whether treatment is complete or whether further oncology consultation and follow-up chest X-rays every few months are needed. Call if the wound opens, pus leaks from it, the patient has a fever or does not eat.

Frequently asked questions