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Module 17 > Approach to Mammary Tumours > Flashcards

Approach to Mammary Tumours Flashcards

1
Q

what is the prognosis of mammary tumours in dogs

A

good or poor

~50% malignant

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2
Q

what is the prognosis of mammary tumours in cats

A

poor

90% malignant

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3
Q

what is the age of mammary tumours in dogs

A

7-13 years

malignant 9-11 y

benign 7-9y

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4
Q

what is the age of mammary tumours in cats

A

10-12y

9y siamese

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5
Q

what breeds are predisposed to mammary tumours

A

miniature and toy breeds

yorkie, poodles, dachsunds, spaniels

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6
Q

what cat breeds are predisposed to mammary tumours

A

oriental breeds (Siamese)

DSH

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7
Q

what are tumour suppressor genes

A

p53, PTEN, E-cadherin, B-catenin

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8
Q

what are oncogenes

A

ErbB2/HER2, COX2, PI3K/AKT/mTOR

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9
Q

what are familial genes for mammary tumours

A

36% of English springer spaniels in Sweden affected by CMT

BRAC1 and BRAC2 germline polymorphisms in in E spr sp associated with increased CMT risk

BRAC1 mutations and decreased expression also seen in other breeds

No evidence for BRAC1 or 2 mutations in cats

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10
Q

what are hormonal causes of mammary tumours

A

Reduced prevalence in countries in which spaying is culturally acceptable

Increased in Norway, Denmark, Mexico, Italy

Ovariohysterectomy in dogs reduces risk of malignant mammary tumours if done <2.5 years

Sexually intact cats have 7 fold higher risk of mammary tumours

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11
Q

how does obesity contribute to mammary tumours

A

Adipose tissue is a source of steroid hormones

Reduced risk in spayed female dogs if thin 9-12 months

Increased risk if obese at 1yr old

Increase risk if obese 1 year before diagnosis

More poorly differentiated (grade III) carcinoma in overweight/obese dogs

Increase aromatase and hormone receptors in obese dogs

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12
Q

how do previous tumours increase risk of mammary tumours

A

Previous mammary tumour increases the risk of second tumour (entire females)

22% of dogs with benign tumour develop another later

49% of dogs with malignant tumour develop another later

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13
Q

what are alternative considerations to consider when palpating a mammary lump (5)

A
  1. last season
  2. recently lactating
  3. painful/non painful
  4. diffuse gland enlargement
  5. rapid/slow growth
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14
Q

what are ddx in dogs

A

Mastitis

Duct ectasia (cysts)

Focal fibrosis

Lobular hyperplasia

Ductal hyperplasia

  • Epitheliosis
  • Papillomatosis

Gynecomastia

  • Sertoli cell tumour — male dogs!
  • Granulosa cell tumour — female dogs?
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15
Q

what are ddx in cats

A

Mastitis

Duct ectasia (cysts)

Focal fibrosis

Ductal hyperplasia

  • Epitheliosis
  • Papillomatosis

Lobular hyperplasia

  • Epithelial hyperplasia
  • Adenosine
  • Fibroadenomatous change (feline mammary hypertrophy) (fibroepithelial hyperplasia/hypertrophy)
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16
Q

when does fibroadenomatous hyperplasia occur in cats

A

Follows metestrus, pregnancy, exogenous progestins

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17
Q

what does fibroadenomatous hyperplasia look loke

A

One or multiple glands are swollen, painful, edematous, but no milk production

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18
Q

what are the clinical signs of fibroadenomatous hyperplasia in cats

A

anorexia

lethargy

tachycardia

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19
Q

how do you diagnose fibroadenomatous hyperplasia

A

Diagnosis on gross appearance and age — young animals

Check if pregnant with US

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20
Q

how do you treat fibroadenomatous hyperplasia

A

Stop exogenous progestins, use progesterone antagonist (Aglepristone), may require ovariohysterectomy

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21
Q

what are the histological types of mammary tumours

A
  1. stromal/connective tissue –> sarcoma
  2. ductal, luminal, myoepithelium –> adenocarcinoma
  3. fat cells –> lipoma
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22
Q

what are the features of mammary sarcomas

A

Highly aggressive — metastasis to bone, lungs etc (hematogenously)

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23
Q

which is the most common type of mammary sarcoma

A

Uncommon (2-3%)

Osteosarcoma (most common), chondrosarcoma, fibrosarcoma, hemangiosarcoma

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24
Q

what are the features of mammary lipomas

A

feels fatty, soft, mobile

benign

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25
what are the type of benign epithelial tumours in dogs
26
what is the most common benign tumour in the dog
mixed mammary tumour
27
what is the appearance of mixed mammary tumours
circumscribed, non-fixed, hard, knobbly cartilage/bone present histologically
28
what are malignant epithelial tumours in the dog
29
what are the features of solid mammary carcinomas
fixed ulcerated rapid growth
30
what are the features of anaplastic epithelial mammary carcinomas
ulcerated dermal and lymphatic invasion
31
what are inflammatory carcinomas
Invasion of dermal lymphatics by tumour emboli causes local edema = definition
32
what are the types of inflammatory carcinomas
many different carcinoma types (aggressive: undifferentiated, anaplastic)
33
do inflammatory carcinomas metastasis
yes early to distant sites
34
what is the appearance of inflammatory carcinomas
erythema firmness warmth pain often no palpable mass
35
when do inflammatory carcinomas occur in the dog
Luteal phase/progestagens Often concurrent cystic endometrial hyperplasia (CEH)
36
what are the ddx to inflammatory carcinomas
acute mastitits dermatitis
37
why is it important to read detail of pathology reports
prognostic significance of tumour type Complex carcinomas Simple carcinomas * Tubulopapillary * Solid * Anaplastic Sarcomas
38
describe the histology of this tumour
well circumscribed clear tubule formation low mitotic rate
39
describe the histology of this tumour
invasive poor tubule formation nuclear pleomorphism high mitotic rate (\>20/10HPF)
40
what is the mammary tumour grading scheme based on
Mammary tumour grading scheme in addition to tumour subtypes, based on human scheme Individual scores added to make total score
41
describe the grading scheme for mammary tumours
42
what additional pathological findings influence prognosis
Surrounding stromal invasion Vascular or lymphatic invasion Lymph node involvement
43
what is the breakdown of bengin vs. malignant and what type in feline mammary tumours
10-20% benign = most are fibroadenomas 80-90% malignant = most simple carcinomas
44
what grades are simple carcinomas usually
high grade
45
are simple carcinomas hormone receptor positive or negative
negative
46
how do you confirm the diagnosis of mammary masses
FNA biopsy
47
what are the problems with FNA of mammary masses
Problems with mixed/heterogenous tumours being unreliable/unrepresentative
48
what can FNA rule out
May rule out non-mammary tumours (ex. MCT, lipoma, abscess)
49
what additional information does biopsy provide
Biopsy will give ore information than FNA (tissue architecture, histological type and grade) Often not necessary for small lesions since surgery technique depends on lymphatic drainage rather than histological type If extensive/untreatable, may want to confirm diagnosis before palliative treatment
50
how do you stage mammary tumours
TLN
51
how do you stage the primary tumour (T)
Perform a thorough clinical examination Palpate both chains and all glands (66% dogs have more than one tumour, 33% cats) Palpate and measure primary tumours in cms (T)
52
why is important to palpate and measure the primary tumour
Size relates to prognosis Malignant significantly larger than benign Solid/cystic? Ulcerated? Fixed to skin/underlying tissues?
53
what is the staging system for T in dogs
54
how does size of the mammary tumour relate to prognosis in dogs
Survival time is better if \<3cm 22 months vs 14 months Reduced recurrence if \<3cm Survival at 2 years is better if \<5cm Worse prognosis if \>5cm
55
what is the staging system for primary tumour in cats
WHO staging system
56
how does size of primary tumour relate to prognosis in cats
Mass \<3cm: median survival 21-24 months Mass \>3cm: median survival 4-12 months NB: size is important independent of LN status
57
what are the lymph nodes that you should palpate to stage for metastasis
N0, N1 axillary, inguinal palpate --\> enlarged, fixed FNA, biopsy
58
how do you measure if there is distasnt metastasis
xray chest, abdomen (medial iliac), skeleton? US abdomen scintigraphy
59
how would you clinically stage for metastasis
CT more details of lungs of metastatic nodules good for bone metastasis (expasile lyitc lesion on scapula)
60
why are bloods important in mammary tumour staging
To evaluate general healthy if old or very severe disease (stage III, IV) Coagulopathies — uncommon except inflammatory carcinoma in dogs (21%) FeLV/FIV status if considering chemotherapy Increased acute phase proteins — in large, ulcerated or metastatic tumours Hypercalcemia — uncommon
61
what is the main treatment of mammary tumours
surgery role of chemo and endocrine therapy unproven
62
what is the normal mammary gland LN drainage in dogs
63
what is neoplastic mammary gland LN drainage in dogs
64
what is neoplastic mammary gland LN drainage in cats
65
what surgery is used to treat mammary neoplasia (4)
1. nodulectomy/lumpectomy 2. simple mammectomy (whole gland removal) 3. partial/regional masetcomy (gland plus other adjacent glands which drain from it) 4. radical masectomy (mammary strip)
66
when is a nodulectomy/lumpectomy indicated
Considered more as a biopsy procedure Unfixed lesions \<0.5cm
67
when is a simple mammectomy indicated
Centrally positioned lesions Fixed or unfixed 0.5-1.0cm
68
when is a partial/regional masectomy indicated
Use to recommended for most lesions in dog Can’t be certain of lymphatic drainage in neoplasia 58% dogs develop new tumour after regional mastectomy
69
when is a radical mastectomy indicated
Use for multiple lesions May reduce new tumour formation in ipsilateral glands in dogs Very low risk of contralateral new tumours No survival benefit in dogs compared to regional mastectomy
70
what are the issues with a radical mastectomy
Can be technically difficult Excessive tension/discomfort Increased risk of dehiscence
71
what is the surgery of choice in cats
radical mastectomy
72
when is a radical mastectomy indicated in cats
Use for multiple or single lesions Bilateral surgery vs unilateral improves survival times
73
how is a radical mastectomy done in cats
Usually staged operations with 2 weeks recovery in between to reduce complications But increased risk of dehiscence and complications with bilateral
74
what is done after surgery
submit for histopathology ## Footnote Definitive diagnosis Evidence of lymphatic spread Check surgical margins Further/bilateral surgery? Removal of LNs?
75
what LNs might need to be removed
Inguinal excised with gland 4 (cat) or 5 (dog) Axillary — remove if enlarged/positive for metastasis or for staging purposes Sentinel lymph node mapping?
76
should you spay at the same time
Benign tumours: reduce risk of growth of further being tumours by 50% Will prevent pyometra Prevents the need for progestins Malignant tumours: Most studies show NO effect on time to metastasis (TTM) or overall survival time (OST) Better to do mammary strips But new data on ER/PR status and serum estrogen levels at the time of surgery
77
should chemotherapy be used
Needed for aggressive carcinomas but not very effective Most evidence supports some efficacy for doxorubicin
78
how does doxorubicin work in cats
Some effect on cell lines in vitro Some effect on gross disease Some effect on median survival time As adjuvant to surgery but no significant difference when concurrent control group used
79
what chemo might work for dogs
Cyclophosphamide with 5-Fluorouracil in dogs? NB 5FU toxic in cats
80
what chemos are useful for carcinomas
Mitoxantrone? Carboplatin? Gemcitabine? Targeted therapy (TKI) may be antiangiogenic too Toceranib (Palladia)
81
what dose of toceranib (Palladia) would be used
10mg M, W, F or 7mg EOD GI signs, weight loss, neutropenia
82
what other therapies are used to treat mammary tumours
1. herceptin 2. anti estrogens 3. cox2 inhibitors (NSAIDs) 4. anti angiogenic therapy
83
what is herceptin
blocks EGFR2/HER2 antagonist increased expression in dog and cat carcinomas but drug not tried
84
what are anti estrogens
tamoxifen/aromatase inhibitor
85
why are cox2 inhibitors used
Increased COX2 expression in aggressive carcinomas and associated with poor prognosis
86
what are anti angiogenic therapies used
Thalidomide
87
what are prognostic factors in the dog
50:50 malignant:benign Histological type * Tubular, papillary - good, solid, anaplastic = poor Histological grade * Well differentiated = good, undifferentiated = poor Tumour size * \<3cm diameter = good * \>5cm = poor Tumour clinical stage Spay status * Not spayed (more likely ER positive) = good
88
what are prognostic factors in cats
80:20 malignant:benign Histological grade * Well differentiated = good but rare! Tumour size * \<2cm diameter = good * \>3cm = poor Tumour clinical stage * Stage 1 = good * Stage IV = bad Extent of surgery: aggressive surgery is best in cats to prevent recurrence —\> bilateral mammary strip down to a clean fascial plane
89
what is the modified WHO staging in dogs
90
what is the modified WHO staging in cats

Module 17 (31 decks)

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