Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FRCR2 > skin > Flashcards

skin Flashcards

1
Q

What genetic condition predisposes to non-melanoma skin cancer and for which RT is contraindicated
What is the defect

A

Xeroderma pigmentosa

Defect in nucleotide excision repair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What should be assessed for skin cancer on examination

A

Size & depth of tumour, fixation to underlying structures, bony involvement
Margins

Regional LN involvement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When is surgery preferred for a skin cancer

A

Young age < 60yrs – cancer risk, RT effect on cosmesis worsens with time
Poor Vascular supply: lower leg – shin/malleoli, dorsum of hand
Large lesions involving cartilage / bone - RT may cause osteoradionecrosis
Upper eyelid (overlying lacrimal gland) - risk of dry eye if gave RT
Prior burns / previous RT
DNA defect syndrome: Gorlin’s, XP, Ataxia telangiectasia - RT could induce tumours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When is RT preferred for skin cancer

A

Provides better cosmesis / functional outcome - nose, lower eyelid, ear, lower lip/commissure
Sites with potential for deep infiltration: inner canthus, nasolabial fold, ala nasi, tragus, post auricular area
Large superficial lesions
Elderly or unfit for surgery
Multiple lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When is adjuvant RT indicated for a skin cancer

A

R1 margin and no further surgery possible (6-10mm margin ideally)
Extensive or large PNI
Multiple risk factors - infiltrative growth pattern, poorly differentiated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is a skin cancer best treated with kV

A

BCC - 5mm margin
SCC - 1cm margin
Deep margin the same - receiving at least 90% of the dose

Protective - Eye shield, mouthguard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What radical dose should a skin cancer receive

A

SCC - 45Gy/10# (if small can hypo fractionate to 35Gy/5#; if large, hyperfractionate to 60Gy/30#)
BCC - 40.5Gy/9#

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are margins altered when treating with electrons
What is the minimal lateral size

A

Need wider margins as dose distribution narrows with depth
40mm min lateral size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What protection is needed when treating eg a lip with electrons

A

lead mouthguard covered in wax due to backscatter of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the depth dose depend on energy for electrons

A

Dx2 = Dmax
Dx3 = D90
dx4 = D50
dx5 = practical range (tail)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What thickness of lead shielding is needed depending on electron energy

A

Energy / 2 = thickness in mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

For photons, where is Dmax in relation to energy

A

Energy/4 = Dmax in mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is a low risk BCC best treated
How is a high risk BCC best treated

A

Low risk - surgical curettage or cautery, topical imiquimod or 5FU

High risk - surgical excision (WLE, Moh’s) or RT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What margin is given for a BCC treated with primary RT

A

Well defined - 5mm margin
Poorly defined or morphoiec - 10mm

If treating with electrons, allow an extra 5mm margin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What percentage of actinic keratosis will transform to SCC per year

A

1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What radical primary RT dose would be given to an SCC

What margin should be included

A

45Gy/10#

Can consider 18-20Gy/1# if elderly & lesion <3cm
35Gy/5# if >4cm

If >5cm - 55Gy/20#
If >6cm - 60Gy/30#

Well defined SCC - 1cm
poorly defined or large (>4cm) - 2cm margin
1cm deep margin
For electrons, add an extra 1cm margin to these

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When should electrons be chosen as treatment modality

A

Over bone and cartilage due to the photoelectric effect
Lesions >4cm
Scalp - drop off of dose minimises dose to brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When should orthovoltage XRs be chosen as treatment modality

A

<1cm depth and <4cm lesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What systemic treatments can be used for metastatic SCC

A

Cisplatin & 5FU (capecitabine) – like head & neck
Cemiplimab – PDL1 inhibitor

20
Q

What is a Merkel cell carcinoma

A

Aggressive neuroendocrine cancer with high risk of spread, typically occurring within H&N area

21
Q

What is the treatment for a Merkel cell carcinoma

A

If operable, surgical resection with 3cm margin and SLNB
If positive LN -> nodal dissection
Adjuvant RT (50Gy/25#) if node positive, >2cm or positive margins

If inoperable - primary RT (60Gy/30#) with 3-5cm margin

22
Q

What are the indications for adjuvant RT for a Merkel cell carcinoma

What dose RT is given adjuvantly

A

Positive margins
Primary tumour >2cm
Node positive

Dose: 50Gy/25#

23
Q

What is the treatment for a metastatic Merkel cell carcinoma

A

avelumab first line
+/- RT to neck nodes

Carboplatin/etoposide 2nd line

24
Q

What is the prognosis for a Merkel cell carcinoma

A

High rate of local recurrence
Median OS – 9 months in metastatic disease

25
Q

What are the 4 types of Kaposi sarcoma

How is it treated

A

HIV related
Immunosuppressed
Classical - indolent, lower limbs
Endemic - sub-saharan africa - aggressive and occurs in children with fulminant lymphadenopathy

Treatment:
HAART
Palliative RT to symptomatic lesions - 8Gy/1#, 20Gy/10# pop
If severe disease - systemic treatment with caelyx or paclitaxel

26
Q

How is a cutaneous angiosarcoma treated

A

Resection with wide margin then 50Gy/25# adj RT
If inoperable, caelyx in combination with RT (60Gy/30#)

27
Q

How is a low grade cutaneous follicular or marginal-zone (MALT) lymphoma treated

A

Superficial RT or electrons
PTV = GTV + 2-3 cm margin
24Gy in 12# or 15Gy in 5#

28
Q

How are cutaneous T cell lymphomas classified

A

Indolent:
Mycosis fungoides / Sezary syndrome – erythroderma, poor prognosis (32m)

Aggressive:
Anaplastic large cell / NK cell lymphoma

29
Q

How are cutaneous T cell lymphomas treated

A

Observe until symptomatic, then PUVA or topical steroids

Palliative RT for symptomatic lesions - 8Gy/2# or 12Gy/3#

Systemic treatment - No benefit of combination treatment (eg CHOP) over single agents: methotrexate, liposomal doxorubicin, gemcitabine

30
Q

What is the treatment for mycosis fungoides

A

Total body electron therapy - 30Gy in 20#

31
Q

How is T staging defined for skin SCC

A

T1 - <2cm
T2 - 2-4 cm
T3 - >4cm or bone invasion or perineural invasion
T4a - gross cortical bone or marrow invasion
T4b - Skull base or axial skeleton involvement

32
Q

How is nodal staging defined for skin SCC

A

N1 - single node and <3cm
N2a - single node 3-6cm
N2b - multiple ipsilateral nodes all <6cm
N2c - bilateral or contralateral nodes ≤6cm
N3 - ECS or LN >6cm

33
Q

What histological markers would suggest melanoma

A

HMB 45, S100

34
Q

What is the Van Herk recipe

A

used to calculate CTV-PTV margin to allow for setup error for EBRT photons

35
Q

What is the 10yr local control rate of BCC

A

<2cm - 95%
>2cm - 90%
deep invasion 50%

36
Q

What are the indications for adjuvant RT for BCC

A

T3 (>4cm)
T4
Positive margins
Perineural invasion
Recurrence

37
Q

First line mx of SCC
Outcomes

A

Surgery - aiming 4mm margin at least

<2cm - 95% 5yr control
2-5cm - 65-85%
>5cm 50-60%

38
Q

Indications for adjuvant RT for SCC

What dose should be given for adjuvant RT

A

Positive margins
Inadequate margins:
<4mm margin for low risk (<2cm)
<6mm for high risk (>2cm or >6mm depth, perineurial invasion)
Recurrent disease
Nodal mets
Perineural invasion and LVI
completely excised T3 (>4cm) tumours, where there are multiple high-risk factors (>6 mm in thickness (depth) and invasion beyond subcutaneous fat)

Dose: 50Gy/25# or 60Gy/30# or 66Gy/33# for high risk H&N SCC

39
Q

What defines a high risk BCC

A

> 2 cm
Morphoeic or infiltrative
Poor margin
Recurrent
Immunosuppressed or Gorlin
Sites – face and scalp, over critical structures
primary surgical closure difficult

40
Q

When is RT preferred

A

Facial triangle - better cosmesis
Large superficial lesions, with no bone involvement

41
Q

When is surgery preferred

A

Large lesions, involving cartilage, bone, tendons or joints (risk of necrosis and lower cure rate)
Young pts - cosmesis and 2nd cancer risk
Areas with poor vascular supply / healing problems / problems with function - lower leg, feet, dorsum of hand and genitalia
Areas likely to result in repeated trauma - elbow
Gorlin’s, xeroderma

42
Q

When is Moh’s surgery preferred

A

Ill defined tumour (ie indistinct clinical margins) or tumour arising in unhealthy or damaged skin
H-zone of the face

Ensures 100% clear margin with minimal tissue resection

43
Q

When is adjuvant RT given to a nodal site for SCC

A

≥3 cm node (n2)
Parotid node metastasis
Multiple involved nodes
Extranodal extension (n3)

44
Q

What is gorlin’s syndrome

A

Autosomal dominant familial cancer = PTCH (patched gene) on Chr 9: q22-31

Multiple BCC at an early age
Mandible bone cysts, rib abnormalities, short 4th metacarpal, coloboma (gap in eye structure), cataracts, fused vertebrae, polydactyly, cleft lip, cardiac tumours

Increased risk of medulloblastoma, meningioma, ovarian fibromas

Skull x-ray shows calcification of falx cerebri in patients >12 years in 90% of cases

Treatment: surgical excision – avoid RT if possible
consider vismodegib

45
Q
A

FRCR2 (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions