Approach to Mammary Tumours Flashcards
What is the most common type of neoplasm in intact bitches?
Mammary tumours
Prognosis of mammary tumor in the bitch
Variable ~50%Malignant
Prognosis of mammary tumour in the queen
Poor-90% Malignant
Dog breeds predisposed to mammary tumours
Miniature and toy breeds- Yorkshire terriers, Poodles, dachshunds, spaniels
Cat breeds predisposed to mammary tumours
Oriental breeds (Siamese), DSH
Mean age of dog to develop mammary tumours
7-13 yrs (malignant 9-11y vs benign 7-9y)
Mean age of cat to develop mammary tumours
10-12 yrs
9yrs (Siamese)
3 main causes of development of mammary tumours
Genes and Hormones and Obesity
Two genetic reasons for development of mammary tumours
Sporadic – Combination of upregulated or downregulated (mutated) genes acquired through life
Familial- Inherited from generation to generation
Ovariohysterectomy in Dog reduces risk of malignant mammary tumours if done______ years
<2.5 years
T/F Previous mammary tumour increases the risk of second tumour
True!
22% of dogs with benign tumour developed another later
49% of dogs with malignant tumour developed another later
Signalment of Fibroadenomatous hyperplasia
Follows metoestrus, pregnancy, exogenous progestins
Young animals- Check if pregnant with US
One or multiple glands are swollen, painful, oedematous but no milk production
Anorexia, lethargy, tachycardia
Adenocarcinoma is neoplasm of what cells (Mammary tumour)
Ductal epithelium
Luminal epithelium
Myoepithelium
A Circumscribed, non-fixed, hard, knobbly, Cartilage/bone presented histologically suggest what kind of tumour?
Mixed mammary tumour
Ep +/- myoep but cartilage or bone always present
Are mixed mammary tumours benign or malignant
Benign
What is the most common malignant mammary tumour in the dog
SIMPLE carcinoma
single epithelium
What is inflammatory carcinoma
Invasion of dermal lymphatics by tumour emboli causes local oedema
Anaplastic definition
A term used to describe cancer cells that divide rapidly and have little or no resemblance to normal cells
Sort by increasing malignancy
Complex carcinomas
Simple carcinomas( Tubulopapillary, Solid, Anaplastic)
Sarcomas
Complex carcinomas
Simple carcinomas( Tubulopapillary, Solid, Anaplastic)
Sarcomas
Indications in histopathological grade for a high tumor grade
Invasive
Poor tubule formation
Nuclear pleomorphism
Hi mitotic count (>20/10HPF)
Outline Mammary tumour grading
Tubule formation
Nuclear pleomorphism (variation in size and shape)
Mitoses / 10 HPF
Graded on a scale 1-3 and added together
Outline how many grades there is in mammary tumour grading
I (Low) Well differentiated (3-5)
II (Intermediate) Moderately differentiated (6-7)
III (High) Poorly differentiated (8-9)
Name 3 types of histological types of mammary tumours
SARCOMA-Stroma/ connective tissue
ADENOCARCINOM- Various epitheliums
LIPOMA- Fat
Are lipomas benign or malignant
Benign
Are sarcomas typically benign or malignant
Highly aggressive – metastasise to bone, lungs etc (haematogenously)
Difference between Solid and Anaplastic epithelial tumour types
Solid- Fixed, Ulcerated, Rapid growth
Anaplastic- Ulcerated, Dermal & lymphatic invasion
Is solid or anaplastc tumour types more malignant
Anaplastic
Is Inflammatory carcinoma common in cats
Few cases reported in cats
Undifferentiated, anaplastic, v malignant carcinomas
Two ways to take a sample of mammary tumour
FNA and biopsy
Diagnosis of mammary tumour using FNA
Sucks out some cells
Usually diagnostic if uniform carcinoma
May rule out non-mammary tumours eg MCT, lipoma, abscess
Advantages of biopsy over FNA
Biopsy will give more information than FNA eg tissue architecture, histological type and grade
Outline the first stage of staging primary tumour (T)
Palpate both chains and all glands (66% dogs have more than one tumour, 33% of cats)
Palpate and measure Primary tumour in cms (T) Size relates to prognosis
Solid/cystic?
Ulcerated?
Fixed to skin/underlying tissues?
Main treatment of mammary tumours
Surgery
Role of Chemotherapy and endocrine therapy unproven
Name of surgery to remove mammary tumour
Nodulectomy/lumpectomy Unfixed lesions < 0.5 cm
Mammectomy (whole gland removal) Fixed or unfixed 0.5-1.0 cm
Partial /regional mastectomy (gland plus other adjacent glands which drain from it)
Radical mastectomy (mammary strip,used for multiple lesions)
What is the surgery of choice of feline mammary tumours
Radical mastectomy
When do I remove lymph nodes for mammary tumour treatment
Inguinal excised with gland 4 (cat), or 5 (dog)
Arguments why I should have a concurrent ovariohystectomy
Benign tumours: reduces risk of growth of further benign tumours by 50% (Kristiansen et al 2013)
Will prevent pyometra
Prevents the need for progestins
Should you use chemotherapy and what drug to give for mammary tumours
Needed for aggressive carcinomas BUT not very effective
Most evidence supports some efficacy for Doxorubicin
Other therapies for mammary tumours
Herceptin (blocks EGFR2/HER2 antagonist)
Anti-oestrogens – tamoxifen/aromatase inhibitor
Cox2 inhibitors (NSAIDs) – increased COX2 expression in aggressive carcinomas and associated with poor prognosis
Anti-angiogenic therapy - Thalidomide
Prognostic factor (Dog)
Histological type: Tubular, papillar, solid, anaplastic
tubular, papillary = good, solid, anaplastic = poor
Prognostic factor (Dog)
Histological grade
Low (grade I) = good, High (grade III) = poor
Prognostic factor (Dog)
Tumour size
<3cm diameter = good, > 5cm = poor
Prognostic factor (Dog)
Spay status
Not spayed (more likely ER positive) = good
ER tumour meaning
Estrogen receptor (ER) positive.
The cells of this type of breast cancer have receptors that allow them to use the hormone estrogen to grow.
Prognostic factor (Cat)
Histological grade
Low (grade I) is good, but less common!
High (grade III) – 90-100% dead at 1 year
Prognostic factor (Cat)
Tumour size
<2cm diameter = good, > 3cm = bad
