MAMMARY TUMOURS - CANCERS

The following is taken from a lecture given on CANINE CANCERS

Mammary tumours of the Bitch are the most common cancer tumour referral seen in vet practice.

25-52 o/o of ALL tumours.

Approx 50o/o benign.

Approx 50o/o malignant with some being MORE aggressive than others.

The condition is rare under 2 yrs of age.

Rare under 5 yrs of age & from then on the “risk” increases.

Susceptible HUNTING BREEDS (HOUNDS & TERRIERS) from figures available.

Genetic factor

? increase if highly in bred.

RISK FACTORS

Any intact female can said to be at risk. There appears to be an increased risk in bitches who have not been bred from or only had a single litter.

Familial history of mammary tumours.

Progestins. Use of in chemical suppression of seasons.

Contra -indications for use of Progestins.
 Do not treat animals with a family history of uterine, mammary or liver disease.

None of the following are proven to have any association with a pre-disposition.

Abnormal  or delayed oestrus cycles.

Pseudo-pregnancy

Pyometra.

Role of spaying as a  “PREVENTIVE”

Between the FIRST & SECOND SEASON, after the SECOND season there is  NO proven value.

Benign Tumours are generally slow in growth, well defined,not large,not inflamed, do not ulcerate.

Malignant Tumours.

Grow quickly; ill defined borders, mass is fixed.

Inflamation.

Ulceration.

Odema…………spread may be indicated by swelling of lymph glands; swelling of a limb with intermittent or progressive lameness. Rapidly can then spread via the  LYMPHATIC SYSTEM to the lungs.

Surgery.  Excellent for benign tumours.

Very variable for malignant tumours. ,better if non-invasive & small – 3cm.

Poor if pre-existing metastases OR a re-currence.

A prognosis can be ascertained from biopsy  results.

ALL cases must be approached individually & the outcome & overall prognosis is very dependent on the type of cancer cell.

Postscript.

Malignant Lymphoma or lymphosarcoma is the most common blood born tumour in dogs,however  more YOUNG dogs do appear to be presenting with this and the AFGHAN  HOUND  is included, certainly from what  I am aware of  in the past 2 years.

SYLVIA EVANS

Notes taken from Malcolm Brearley's Lecture by Sylvia Evans

KNOWN CAUSES OF CANCER (RISK FACTORS)

For an increasing number of human cancers the cause IS known.

Some of these risk factors may include smoking (lung cancers); certain viruses (cervical cancers) and ultra-violet sunlight (skin melanomas).

In addition, certain genes present in some families have been identified (breast cancers in woman)

In dogs & cats there are only a few known, or currently identified risk factors for cancer.

In cats the virus known as Feline Leukaemia Virus is a definite trigger for certain cancers (Feline Lymphoma & Leukaemia), however not all cats that are infected with FeLV will develop cancer & conversely not all lymphomas in cats are induced by FeLV infection.

BREED RELATED CANCERS

Certain breeds of dogs do appear to be susceptible to specific tumours.

Some of these and other breed related tumours ARE highly suggestive of a widespread genetic susceptibility for the specific cancer within the breed. The  truly hereditary cancers (ie that are passed down certain lines) however are rare in dogs.

Malignant Tumours or CANCERS are the most aggressive.They invade into surrounding tissues and have the ability to produce secondary tumours that make them so life threatening.

BENIGN TUMOURS only grow locally and do not spread however they are capable of causing serious problems just because of their physical size or position.

There are many different types of cancer and each behaves in a slightly different way, it is therefore vital to have a sample of the tumour sent for examination by a pathology laboratory.

CANCER is one of the most treatable of ALL CHRONIC ILLNESSES.

There are MANY types of tumours and the treatments afforded to each will vary.

To ensure the most effective treatment is given and to get an idea of the likely outcome, a variety of tests may be necessary, including a biopsy. Contrary to popular belief, taking a biopsy does NOT increase the risk of spread, IF PERFORMED CORRECTLY.

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