Skin Cancer other than Melanoma FRCR CO2A Flashcards
Commonest cancer in the UK
Non melanoma skin cancer
premalignant conditions of skin
- actinic keratosis
- Bowen’s diseasee
- Erythroplasia of Queyrat
- Paget’s disease
Malignant tumors of skin
- BCC
- Sq CC
- Merckel Cell CArc
- Amelanocytic melanoma
- Cut T Cell Lymphoma
- Primary Cut B Cell Lymphoma
- Kaposi’s Sarcoma
- Angiosarcoma
Incidence of Non melanoma skin cancer in UK
100,000 cases in UK in 2010
500 annual deaths
5% of people > 60 yrs develop this cancer
RFs for skin cancer
Chronic Sun Exposure and UV radiation
Actinic keratosis and Bowen disease
Immnosuppression (AIDS, CLL, CML)
RT exposure
Chemicals like nitrates, arsenicals in tonics and pesticides
Genetic Predisposition for skin cancer other than melanoma
- Gorlin’s syndrome
- Bazex’s syndrome
- Xeroderma Pigmentosa
- Ferguson Smith disease
- Muir Torre syndrome
What is Gorlin’s syndrome?
Autosomal familial cancer
multiple BCCs at early age
gene: PTCH on Chr 9q22-31
what other abnormalities are a/w gorlin syndrome
- bone cysts of mandible
- abnormalities of ribs, short 4th metacarapal
- Coloboma at birth or cataracts in later life
- increased risk of medulloblastoma and meningioma
Defect in Xeroderma Pigmentosa
defective DNA repair (nucleotide excision repair)
what is erythroplasia of queyrat a/w
sq cell carc of glans penis
BCC among skin cancers
80 % of all non melanoma skin cancers
Causes of BCC
- UV Radiation
- fair complexion, red or blonde hair
- light eye color
common sites of BCC
Sung exposed region
1. Head n Neck
2. Trunk
s/s of BCC
grow very slowly over years
itching, bleeding, discomfort
infiltrate locally and destroy local tissues
Nodular BCC
pearly papule with rolled border, central crusting or ulceration
superficial spreading BCC
scaly erythematous patch or plaque, brown due to melanin pigmentation
molecular pathogenesis of BCC
- Hedgehog (HH) signaling pathway
- mutations in TP53
pathogenesis of Sq Cell Carc
progression thorough dysplasia, carcinoma in situ, or Bowen’s disease to frankly invasive sq cell carcinoma
Hx of keratocanthoma
histologically similar to Sq cell carc but grows rapidly 4 to 6 weeks that subsequently under goes spont regression, leaving a small pitted scar on the surface
what are the poor prognostic factors for Sq cell carcinoma skin
- tumor size > 2cm
- poorly defined borders
- location on the central part of face and ears
- long standing duration
- incomplete excision
- recurrent cancer
- prev site of RT
- immunocompromised pts
What should be asked in Hx with skin cancer pt?
- any past high sun exposure
- topical treatment used in past
- chemical exposure
- previous irradiation
- rate of growth
How rate of growth helps to differentiate difft types of skin cancer
presents for years and slow growing: BCC
months: sq cell carc
weeks: keratoacanthoma
palpation for skin tumors
margins and depth
why depth Palpation?
to chose type of RT and energy to be used
skin cancer Dx
punch biopsy, excisional biopsy or scrapings
when is CT required for skin cancer
for deep involvment
when is MRI helpful for skin cancer?
PNI
Surgeries for skin cancer
- Mohs micrographic surgery
- Surgical excision
- curettage and electro desiccation and cryosurgery
WHat is Mohs micrographic Surgery?
rapid examn of frozen section to examine peripheral and deep surgical margins
determine whether further excision required or not
cure rate at 5 yr: 99%
Advantage of surgical excision over RT
complete removal confirmed histopathological and long term f/u can be avoided
Indications for Sx over RT
- younger than 60 yrs
- recurrent tumors
- uncertain or incomplete margins
- involving cartilage, tendon, bone or joint
Non Surgical Rx for skin cancers except melanoma
- Imiquimod 5%
- PHotodynamic therapy
- Topical 5 FU therapy
- RT
Imiquimod 5% ?
topical immune modulator, OD 5 days per week for 6 weeks
RT uses in skin Cancer?
- Older pts
- multiple tumor or larger tumors
- sites where surgery is difficult
- refuse surgery or on anticoagulant
Cure rate of RT for skin cancer
95% at 5 yrs
C/I for RT
- Xeroderma Pigmentosa
- Basal Cell Naevus Syndrome
which sites poorly tolerate RT ?
- sites of prev RT
- areas of vascular insuffy
- skin overlying the shin
- malleoli of the lower leg
- middle 3rd of upper eyelid
- dorsum of hand
acute side effects of radiotherapy for skin cancer
dry inflamed red skin
Scabing
ulceration
Intermediate side effects of radiotherapy for skin cancer
slow healing over 4 to 8 weeks
tiredness
watery eyes
How can watering eyes be treated?
if d/t Nasolacrimal duct stenosis, Recanalisation
Late RT S/Es for skin cancers
radiation dermatitis
telangiectasia,
fibrosis
permanent hair loss on scalp
dry eye due to lacrimal gland damage
2ndary malignancies
why is wax bolus added for electron therapy?
to increase the surface dose to 90 % isodose, to cover the PTV
Why wider margin (1.5 cm ) for electron therapy?
Bowing of the isodoses
Eye Shield
inner surface coated with liquid paraffin to reduce friction with cornea
for how long eye pad has to worn on by pts post LA to eye
2 hrs, till corneal reflex is back to normal
Choice of RT for tumors < 4 cm and thickness < 5 mm
Superficial X Ray (90 to 150 kV)
Choice of RT for tumors > 4 cm and thickness 5> mm
Electron therapy
at which sites should e therapy be avoided
- near the eyes, bcoz wide margins are required, more scatter dose, difficult to shield
- nasal cavities
- sinuese, mastoid air cells
Bcoz of uncertain dose distribution
what energy of electron should be used
depth x 3 (MeV)
RT dose Schedules for skin cancers
- small BCC (< 3 cm): 35 GY/ 5# over 5 days to the 100 % isodose
- For large BCC and sq cell carcinoma: 45 Gy/ 10# or 55 Gy/ 20 # to 100 % isodose
- for very large: 64 Gy/ 32# to the 100 % isodose
Adj RT Dose
50 Gy/ 20#
or 60 Gy/ 30# to 100% isodose
Interstitial BT dose for skin cancers
45 Gy/ 10#
Precautions during skin RT
- wash area with plain running water in a shower or bath every day and pat it dry
- avoid shaving and deodorants and soaps
- Avoid sun exposure
why should deodorants and soaps be avoided during RT
sensitize skin to radiation (heavy metals increase PE effect)
mBCC Rx (NCCN 2025)
- Vismodegib
- Cemiplimab
mSq Cell CArc skin Rx
Cemiplimab
- Pembrolizumab
- Nivolumab
what if * If ineligible for or progressed on immune
checkpoint inhibitors
Carboplatin + paclitaxel ± cetuximab
EGFR inhibitors (eg, cetuximab)
Merkel Cell Carcinoma Pecularities
- highly malignant
- develops satellite tumors and LN mets
- elderly
- Neuroendocrine origin (APUD) system
Presentation of Merkel cell carcinoma
painless, red, indurated nodule or an ulcer in H & N region
Rx of Merkel Cell carcinoma
WLE and SLNB with IHC analysis
what if SLNB + in MCC
Nodal dissection f/b RT
mMCC Rx
Carboplatin and Etoposide
malignant porocarcinoma and eccrine carcinoma Rx
WLE
Types of Kaposi Sarcoma
- HIV related Kaposi Sarcoma
- Classical Kaposi sarcoma
- Endemic Kaposi sarcoma
- Kaposi sarcoma in immunocompromised state
where is endemic kaposi saroma?
sub saharan Africa
Presentation of Kaposi Sarcoma
small, painful, reddish or purple papules on face, hard palate, gums, shins, lower legs, soles of the feet
ulceration, H’ge and dental instability
HIV Rx in Kaposi sarcoma
immediately start HAART, many lesions disappear
RT dose for nodular localized Kaposi sarcoma
8 Gy SF with SXR or electrons
mucosal tumors kaposi sarcoma RT dose
20 Gy / 10 # over 2 weeks
Classic non HIV kaposi sarcoma RT dose
16 Gy/ 4 # over 8 days
chemotherapy for kaposi sarcoma
PLD and Paclitaxel
keloid Scar RT
post Sx (excision) to avoid recurrence
6 Gy Single exposure with SXR if less than 2 cm
12 Gy/ 3# with electron if > 2 cm
How effective is RT for keloid scar
effective in 80% cases
Dermatofibrosarcoma Protuberans Rx
WLE with Mohs micrographic surgery
