mammary tumours Flashcards
what statistic of mammary neoplasias in dogs and cats are malignnat?
50% of mammary tumours in the dog are malignant and up to 50% of these have metastasized by the time of presentation
85% of mammary tumours in cats are malignant
what are the predisposing factors of mammary tumours?
- Previous use of progestogens (usually benign lesions)
- Early ovariectomy reduces the risk of mammary neoplasia
Protective benefit of neutering: - 0.5% if spayed before 6 months
- 8% if spayed before 6 -18 months
- 26% if spayed after 18 months
No protection is spay after 2 years - Obesity increases the risk of mammary neoplasia
- It is not clear if lactation / pseudopregnancy have any impact
what signs of mammary glands indicate poorer prognosis?
- Rapid growth
- Poor delineation / infiltration into adjacent tissue
- Inflammatory changes (lymphedema of vulva or limbs)
- Ulceration
- Metastasis to regional lymph nodes or lung, liver, bone
- Tumour size at presentation
- In dogs less than 3cm has better prognosis
- In cats greater than 0.75cm has poorer prognosis
what is the general workup of mammary tumours?
should you take a biopsy of a mammary tumour?
- Small nodules: yes (excise it)
- Suspect inflammatory carcinoma: yes
But generally:
* Therapy does not alter based on the biopsy
* Sometimes it is just as easy to remove the gland as to biopsy it
* Better to spend the money and time on staging
* Examine the local lymph nodes (FNA)
* Both lateral thoracic radiographs
Should I submit resected tissue for histopathology: Yes
what are the options for surgical techniques for mammary tumours?
what factors impact which surgical technique is used?
Options are:
* Lumpectomy (removing lump from within the gland)
* Single mastectomy (one gland)
* Regional mastectomy (more than one gland)
* Complete mastectomy (all glands - either unilateral or bilateral)
Which surgical technical used will be guided by:
* Size and number of tumours
* Location of the tumour - anatomy
* Reported rate of growth
* Condition of the animal
* Dog or cat?
*
- Masses less than 1cm in diameter and firm on palpation can be treated by …..
- Masses greater than 1cm and those attached to skin or deeper tissue should be treated by …….. ………
- Masses greater than 1cm with indistinct border should be treated by ………….. which may be ………… or ………… ……………. depending on clinical staging
- Multiple masses can be treated by ………….. …………… or ……………. ………………… depending on clinical staging
- Masses less than 1cm in diameter and firm on palpation can be treated by lumpectomy
- Masses greater than 1cm and those attached to skin or deeper tissue should be treated by single mastectomy
- Masses greater than 1cm with indistinct border should be treated by mastectomy which may be regional or complete unilateral depending on clinical staging
- Multiple masses can be treated by regional mastectomy or complete unilateral depending on clinical staging
what is the anatomy of the mammary lymphatics ?
Anatomy of the Lymphatics
Axillary and inguinal lymph nodes
Lymphatic drainage runs cranial from 1 and 2 (and 3)
Lymphatic drainage runs caudal from (3) and 4 and 5
regional masectomy:
Glands may need to be removed in groups if lymphatic spread is possible (i.e. based upon clinical staging)
state which glands are removed with others:
Gland 1
Gland 2 – remove with 1
Gland 3 – consider remove all
Gland 4 – remove with 5
Gland 5
what is used to stage mamary tumours?
primary tumour size,
regional lymph node involvement (palpation and FNA),
metastisis - (thoracic radiography)
what treatment is needed for cat mammary tumours?
Always treat cat mammary tumour more aggressively
** Radical mastectomy is recommended**
Increases chance of removing all affected tissue
Decreases chance of local recurrence
what are the additional treatments for mammary neoplasias?
NSAIDs (COX-2) have both anti-inflammatory and anti-neoplastic function often given prior to surgery
OVH is often recommended to prevent exposure to oestrogen and progesterone (remember mammary tumours often have receptors to these), sometimes this is done at the same time as the mammary surgery
Chemotherapy may be used in non-resectable or stage 4 or 5 tumours. Combined therapy with more than one drug is often recommended but the specific regimes are out of scope for this lecture
Laila is 4 weeks post whelping (and is still suckling) and has developed necrotic mastitis
How will you manage this case?
Do not try to suture
This will need to slough
Prevent interference from pups
Antimicrobials will be required (transfer to pups)
May need to consider halting lactation by weaning and administration of cabergoline
what is galactostasis?
when is it seen?
what is the treament?
- Congestion of the mammary gland
- Seen close to parturition / after weaning / rarely in pseudopregnancy
- Engorgement and pain of the gland
- May lead to failure of milk letdown immediately post-partum
- Treatment is reducing food intake, cold packs and encouraging of sucking or milking
- May required cabergoline
what are the two types of agalactia?
what are the reasons for these types?
what is the treatment for each?
Can be a failure of milk production
* Inadequate mammary development
* Early caesarean
* Treated by administration of metoclopramide
Or, failure of milk letdown
* Seen in nervous bitches where adrenaline blocks oxytocin release
* Treated by administration of oxytocin
N.B. Metritis, systemic infection and mastitis can lead to agalactia and requires treatment of the underlying cause
Tara is 8 weeks post whelping (2 weeks after weaning) and has a foul smelling and discoloured milk discharge from one nipple
How would you manage this case?
Hot packs / stripping
Antimicrobial treatment
Consider cabergoline
