Topical Anticancer Agents

Question 1

What are the indications for DCP?

Answer 1

Wart
Alopecia areata
Melanoma in transit

Question 2

What are the contraindications to DCP?

Answer 2

Pregnancy
Children <10 years
Atopic dermatitis

Question 3

What is the process for administering DCP?

Answer 3

Priming: 3 drops 2% DCP in Finn chamber to upper inner arm, leave on 48 hours and review ?sensitisation

Wart
Treatment: 0.1% DCP + 15% salicylic acid in white soft paraffin
Apply 3 times a week (with gloves & toothpick)
Wash off in AM, pare/pumice

Alopecia areata
0.001% DCP in aqueous cream
—> 0.01%
——> 0.1%
Until eczematous reaction
Wash off AM
Follow up 2 weeks
Treatment duration 1-3 months

Question 4

What are the adverse effects of DCP?

Answer 4

Common: contact dermatitis, lymphadenopathy, blistering, skin infection

Uncommon: urticaria, EM, vitiligo/leukoderma, PIH

Question 5

How do you manage generalised dermatitis/urticaria due to DCP?

Answer 5

Cease DCP
Empathise
Explain pathogenesis
Explore dosing/application technique

Cetirizine +- phenergan
Prednisone 0.5-1mg/kg/day tapered over 2-3 weeks

Question 6

What are the indications for cantharadin?

Answer 6

Wart
Molluscum contagiosum

Question 7

What are the contraindications to cantharadin?

Answer 7

Hypersensitivity
Lesion on mucous membranes
Mosaic warts
Circulatory disease eg diabetes, PVD

Question 8

What are the adverse effects of cantharadin?

Answer 8

Pain, ICD, PIH
Annular ring wart
Cellulitis/lymphangitis

Rare: kidney or liver injury, GI haemorrhage, coagulopathy, seizure, arrhythmia, shock

Question 9

What formulations does cantharadin come in?

Answer 9

Cantharadin (plain) 0.7%

Cantharadin plus 1%
+ podophyllin 5%
+ salicylic acid 30%

Question 10

How is cantharadin applied for the treatment of warts?

Answer 10

Pare/shave wart
Apply cantharadin with toothpick
Apply non porous adhesive tape and leave on for 4-6hours
Remove tape and wash site

Advise patient/parent that blister forms 24-48 hours and dries up/falls off after 1 week
80% cute rate

Retreatment 1-3 weeks

Question 11

How does the use of cantharadin differ between warts and molluscum contagiosum?

Answer 11

No occlusion
Can be combined with aldara

Question 12

What is the MOA of imiquimod?

Answer 12

Potent TLR 7 & 8 agonist

Question 13

What are the contraindications to the topical anticancer agents?

Answer 13

Hypersensitivity
Pregnancy/lactation
Dihydro-pyrimidine dehydrogenase deficiency (efudix)
Marked hyperkeratosis
Ulcerated/broken skin
Large lesion/treatment area
Perioroficial site
Infiltrative/recurrent/high risk lesion
Photosensitivity
Immunosuppression
Decreased haematological reserve (imiquimod)
Autoimmune disease (imiquimod)
Unreliable patient

Question 14

What is the MOA of efudix?

Answer 14

Topical chemotherapeutic agent that selectively effects dividing cells

Acts as an antimetabolite —> blocks DNA synthesis —> prevents cell proliferation —> cell death

Question 15

What is the MOA of topical diclofenac?

Answer 15

Unknown
?inhibits COX2 pathway leading to reduced PGE2 synthesis

Question 16

What are the contraindications to topical diclofenac

Answer 16

Hypersensitivity
Pregnancy/lactation
Concomitant use of benzyl alcohol
Skin wound, infection, dermatitis
GI ulceration/bleeding
Cardiac/hepatic/renal impairment

Question 17

What are the adverse effects of topical diclofenac?

Answer 17

Application site reactions eg rash, ACD, xerosis, pain, burning, pruritus

Question 18

How is topical diclofenac dosed and what instructions should the patient be given about it’s use?

Answer 18

Apply BD for 90 days

Do not apply to broken/infected skin
Do not occlude
Avoid eyes, mouth
Photoprotect

Question 19

What are the dosing regimes for efudix in
1. Actinic keratoses
2. Bowen’s disease
3. Superficial BCC

Answer 19

1. Once to twice daily 3-4 weeks
2. Twice daily for at least 6 weeks
3. Twice daily for at least 6 weeks

Question 20

How do you manage efudix & imiquimod local skin reactions?

Answer 20

1. Stop efudix
2. Cold compress
3. Saline soaks
4. Paracetamol
5. Bland emollient +- wet dressings
6. Microbial swab —> treat if indicated
7. Advantan ointment daily for 7 days (if severe) - DO NOT use in imiquimod

Question 21

What instructions should patients be given about how to apply efudix?

Answer 21

Consider pretreating hyperkeratotic lesions
Wash & dry skin
Apply thin film of Efudix onto lesion with non-metal applicator or glove
Avoid eyes, nares, mouth, ears
Wash hands afterwards

Apply >60mins before bed
Sun protect
Do not occlude
Advise patient it is normal for skin to become red, swollen & tender but if reaction excessive, miss dose or two
Review at 2 weeks

Question 22

What are the adverse effects of efudix?

Answer 22

Application site reactions: pain, itch, burning, crusting, weeping, ACD, photosensitivity

Dyspigmentation, scarring, ulceration, secondary infection

Systemic: fevers, URTI sx, mouth ulcers, GI effects, lethargy, malaise

Question 23

What are the adverse effects of imiquimod?

Answer 23

Local skin reaction: redness, oedema, irritation, flaking/scaling, crusting, ulceration, itch, burning, vesicles/bullae, Dyspigmentation

Systemic:
flu-like sx
GI effects
skin infection
flare of autoimmune disease, EM/SJS

Question 24

What is the PBS criteria for treatment is superficial BCC with imiquimod?

Answer 24

Previously untreated
sBCC confirmed by biopsy
Not suitable for cryotherapy or C+C
Pt must have normal immune function
Pt must require topical therapy

*Date of report and pathology company must be provided

Question 25

What are the dosing regimens for imiquimod in
1. Actinic keratoses
2. sBCC
3. Condyloma acuminatum/wart
4. Lentigo maligna

Answer 25

1. 3 times per week in 4 week cycles
2. Weekdays for 6 weeks
3. 3 times per week for up to 16 weeks
4. Weekdays for up to 12 weeks

Question 26

What instructions should be given to patients about how to use imiquimod?

Answer 26

Wash area and dry thoroughly
Apply to lesion with 1cm margin
Rub in until no longer visible
Wash hands after application
Leave on for 8 hours and wash off mane