Mammary tumours are incredibly common in rats and most owners are very familiar with encountering these growths on their pets. However, many owners are not aware of the different options that are available for the treatment of mammary tumours in rats.
Why are mammary tumours so common in rats?
Mammary tumours grow in rats due to the presence of a hormone called Prolactin. This hormone is secreted during the normal oestrus cycle of the rat. It can also be secreted by the mammary tumour itself and by tumours of the pituitary gland. Secretion of Prolactin increases as rats age. Factors which affect the development of mammary tumours in rats include the genetic strain of the rat, the diet, the hormonal status and the age of the rat. Mammary tumours may affect up to 90% of intact female rats and 16% of intact males over one year of age. Approximately 80% of mammary tumours in rats are benign but 20% are malignant.
How can mammary tumours be treated?
All mammary tumours should be surgically removed as early as possible. Benign tumours can usually be completely removed at the time of surgery but this is difficult to achieve with malignant tumours. Alongside surgical removal of the tumour, we can now offer some other options to reduce the likelihood of any future mammary tumour growth. These are:
Placing a hormone implant under the skin. The implant prevents the secretion of Prolactin, which means that mammary tumours are unable to develop. This can be placed at the time of surgery. Alternatively, this can be placed in young female rats to prevent development of mammary tissue.
Neutering. Females can be spayed and males castrated. This removes the influence of Prolactin. NB: These methods are not effective if a pituitary tumour is the source of the prolactin. Also, this will not prevent regrowth or spread of malignant mammary tumour.
Medication to reduce the secretion of Prolactin. This will remove the influence of Prolactin on mammary tissue. This can be effective even if a pituitary tumour is present.
Diet and environment. Reducing the calorie content of the diet and environmental enrichment will reduce the likelihood of mammary tumours recurring.
If you would like to discuss any of these treatment options, please contact us at MKVG.