Non-Melanoma Skin Cancers Flashcards
1
Q
Epidemiology
A
- M:F is 2:1 but BCC increasing in younger women
- skin cancer is the most common of all cancer types
- accounts for 1/3rd of new cancer cases in Canada
- Average age is greater or equal to 60 years
- BCC:SCC is 5:1
2
Q
Why is the incidence of skin cancer rising?
A
Rising due to:
- Changes in lifestyles/fashion (e.g. tanning, increased exposure)
- Occupation
- Geographic location
- Fair skinned, light coloured eyes and hair
3
Q
Etiology
A
- Exposure to UV light (UVA and UVB)
- ionizing radiation exposure
- immunologic deficiencies
- chemical carcinogens
- ulcers
- history of keratosis pilaris
- HPV infections
4
Q
BCC/SCC precursors
A
- Actinic keratosis: in-situ dysplasias resulting from chronic sun exposure
- Arsenical keratosis: caused by arsenic
- Bowen’s disease: SCC in-situ
- Keratoacanthoma: pilosebaceous glands, resembles SCC
5
Q
BCC
A
Arise from basal layer of epidermis
Common on head, neck, face (central portion of body)
6
Q
SCC
A
Arise from keratinocytes of epidermis
Common on face, lips, back of hand, ears, preauricular, temporal, scalp, skin of neck
7
Q
BCC appearance
A
- Shiny translucent or pearly nodule
- pearly borders with telangiectasia and central ulceration (rolled border)
- a pink slightly elevated growth
- reddish irritated patches of skin
- waxy scar
8
Q
BCC spread/growth
A
- local, lateral growth
- slow growing; good prognosis
- if left untreated it can cause extensive damage but it’s rare to spread to other parts of the body
9
Q
SCC
A
- rough or scaly area of the skin
- non-healing ulcer or crusted over patch of skin
- wart like growth
- lacks pearly rolled border and telangiectasia of BCC lesions
10
Q
SCC spread/growth
A
- grows more rapidly than BCC
- more likely to spread
- locally invasion at depth
- hematogenous spread 10%
- lymphatics involved
11
Q
Investigation of all skin lesions
A
- Physical observation-non healing lesion is indurated, scaly and hypertonic
- History (of duration and changes)
12
Q
Types of biopsy’s
A
- Shave biopsy: raised lesions
- Punch biopsy: 2-4 mm of most abnormal looking skin
- Incisional biopsy: remove piece of tissue from lesion
- Excisional biopsy: remove whole mass/lesion
13
Q
Type of treatment dependent on: (7)
A
- size of lesion
- anatomic location
- depth of invasion (risk of recurrence)
- degree of cellular differentiation (risk of recurrence)
- history of previous tx (risk of recurrence)
- patient condition-age, health status
- location of lesion with respect to cosmoses
14
Q
High risk factors
A
Disease factors:
- depth of invasion >2mm thickness
- anatomic location (ear, lip)
- differentiation (poorly or undifferentiated)
- rapidly growing
Patient factors:
- immunosuppression
- unprotected exposure to UV light
- History of skin cancer
- Xeroderma pigmentosum
15
Q
TNM staging
A
Review slides
16
Q
Primary treatment for NMSC?
A
Surgery is primary tx
- Excisional
- Moh’s surgery
- Curretage and electrodessication
- Cryosurgery
- Laser
Can also have RT, photodynamic therapy or topical chemo
17
Q
When is surgery recommended for NMSC?
A
- radiation-induced tumors
- persistent or recurrent disease following RT
- scarred or unhealthy skin
- age < 50 years (cosmesis)
- sites where RT is poorly tolerated (dorm of hand, perineum, sole of foot)
- very large tumors
- tutors involving cartilage or bone
18
Q
When is RT recommended for NMSC?
A
- when the tumor is large
- patient is a non-surgical candidate
- lesion is not resectable
- extensive disease
- recurrent after surgery
19
Q
Advantages and disadvantages of orthovoltage for NMSC
A
Advantages:
- high surface dose
- doesn’t penetrate deeply
- treatment simple, same or next day RT
Disadvantages:
- greater absorption in bone
- isocurve are bowed out at edges
- doesn’t effectively treat at depths greater than 2-3 cm deep
20
Q
Orthovoltage dose
A
Dependent on:
- size
- pathology
- number of fractions
- total time
3000-5500 cGy/ 10-15 fractions
50-300 kV energy
21
Q
When is mega voltage used to treat NMSC
A
for treating associated nodal disease
- spares bone and cartilage
- penetrates deeper
- requires use of bolus
22
Q
Advantages and disadvantages of electron therapy for NMSC
A
6-10 MeV
Advantages:
- surface dose (75-95%)
- nose/ear lesions
- lesions >3 cm in diameter and >0.5 cm thick
Disadvantages:
- shape of isodose curve (dec dose at edges)
- surface curvature affects isodose distribution
- practicality of apportioning large applicators
23
Q
Electron therapy doses
A
4500 cGy/ 10 fractions
5000 cGy/ 15 fractions
5500 cGy/ 20 fractions
24
Q
Advantages and disadvantages of mould brachytherapy for NMSC
A
Advantages:
- short treatment times (3-7 days)
- Sharp fall off in %DD (useful over bone or cartilage)
Disadvantages:
- Time consuming/ careful planning
- inferior cosmesis
25
Advantages and disadvantages of Interstitial brachytherapy for NMSC
Advantages:
1. short treatment times
2. works well for lesion thickness of 1-1.5 cm
3. often external RT came first
Disadvantages:
1. difficulty obtaining even dose distribution
2. time/cost to plan
3. unsuitable near eye or cartilage due to increased local dose
26
Acute and chronic side effects of RT
Acute:
- erythema
- dry/moist desquamation
- scab formation
- epilation
Chronic:
- hyper or hypo pigmentation
- atrophy
- telangiectasia
- fibrosis
- hypersensitivity
27
5 year survival for low risk disease (T1)?
95-99% but 30-50% will have another NMSC within 5 years
28
Merkel Cell Tumor
- arises from neural crest cells
- situated in the basal layer of epidermis and hair follicles
- fleshy nodule, red or blue in colour, H&N
- merkel cells important for tactile function
- rare tumor
- aggressive early spread via lymphatics and blood
- surgery then RT then chemo
- RT fields large to cover enough skin
- poor prognosis in later staged disease
29
Merkel cell epidemiology
- 80% caused by Merkel cell polyomavirus (MPV), 20% unknown
- excessive exposure to UV light
- immunocompromised
- older age (average 75 years)
- fair-skinned women
30
Merkel cell carcinoma diagnosis
- physical
- biopsy
- SLB
- chest xray or CT
- PET
31
TNM staging
Review slides
32
Treatment options for Merkel cell carcinoma
1. Surgery: 1-2mm margin; Moh's
2. Radiation: 60 Gy/ 30 fractions
3. Chemo: adjuvant (cisplatin or carboplatin)
4. Systemic immunotherapy: Avelumab
33
Merkel cell carcinoma 5 year survival
Early stage: >80%
Once metastases occurs: <50%
Recurrence 5 year survival: 30-64%
Local recurrence rate: 26-44% after primary tx
