Download - Squamous cell carcinoma skin
Squamous cell carcinoma (SCC)
Dr Nabeel Yahiya
Kottayam Medical college
skin cancer is the most common of all cancers
97% of these are nonmelanoma skin cancer
(NMSC).
Basal cell carcinoma (BCC) comprises about
80%
Squamous cell carcinoma (SCC) 20% of NMSC
Exposure to ultraviolet solar radiation, especially
ultraviolet B
Painful sunburn before age 20 is related to later
development of premalignant lesions as well as
NMSC and melanoma
Cumulative lifetime sun exposure is related to
increased risk of SCC and BCC.
Host risk factors
blonde or red hair, fair complexion, blue
eyes, and tendency to burn rather than tan
Genetic predisposition
xeroderma pigmentosum
basal cell nevus (Gorlin's) syndrome
epidermodysplasia verruciformis
Muir-Torre syndrome
Porokeratosis
Bazex syndrome
Rombo syndrome
Albinism
phenylketonuria.
Infections- An association exists between
cutaneous SCC and human papillomavirus
Immunosuppression- Transplant recipients on
immunosuppressive therapy
AIDS , multiple myeloma, leukemia, and
lymphoma also are at increased risk
more frequent and aggressive in areas of chronic
skin damage
ulcers, osteomyelitis, sinus tracts and burn
(Marjolin's ulcer), or vaccination scars.
Areas of chronic skin inflammation
discoid lupus erythematosus, lichen sclerosus,
lichen planus, dystrophic epidermolysis bullosa,
and lupus vulgaris
IONIZING RADIATION
Exposure to ionizing radiation is a risk factor for both BCC and SCC
especially in those people with sun-sensitive phenotype and younger age at exposure
risk is directly related to cumulative radiation dose
Increased incidence of NMSC also occurs with chronic radiation dermatitis following therapeutic radiation.
Chemical skin cancer carcinogens
Arsenic (herbicide, pesticide ), soot, and
polycyclic aromatic hydrocarbons from coal tar,
cutting oils
An association exists between cigarette or pipe
smoking and cutaneous SCC
Actinic (Solar) Keratoses-
Actinic keratoses tend to be multiple.
AKs are red, pink, or brown papules with a scaly
to hyperkeratotic surface
They occur on sun-exposed areas and are
especially common on the balding scalp,
forehead, face, and dorsal hands
Malignant transformation to SCC occurs in about
1% of lesions
with cumulative lifetime risk 6% to 10%
depending on number and length of time lesions
are present
Treatment
Excision
Cryotherapy
desiccation and curettage
Dermabrasion
topical therapy with 5-FU or imiquomod
laser resurfacing.
Bowen's Disease
typically appears as a reddish-brown
scaly patch or thin plaque on the sun-exposed
head, neck, extremities, or trunk of an older
individual
On histopathologic evaluation demonstrates full-
thickness epidermal atypia, with more
pronounced nuclear polymorphism and
apoptosis
Other features include confluent parakeratosis,
and, not infrequently, the adnexal extension of
neoplastic cells
It may arise from a pre-existing actinic keratosis
or de novo.
Progression to invasive SCC occurs in 5% to
20% of cases
TREATMENT
Surgical excision is usually preferred
radiation therapy may be considered as an
alternative.
45 to 50 Gy at 2.5 to 3.5 Gy per fraction
Facial lesions require 56 Gy at 2.0 Gy per
fraction for improved cosmesis
Keratoacanthoma
benign, self-healing lesions
presents as a rapidly enlarging papule that
becomes a crateriform nodule with a central
keratinous plug over a period of weeks to
months.
have the potential to destroy large volumes of
tissue and may be associated with SCC
Lesions can be treated with radiation
Doses of 35 Gy in 12 to 14 fractions or 45 Gy in
15 to 20 fractions have been used
Lentigo Maligna and nevi are precursors of
melanoma
a neoplasm of keratinizing cells that shows
malignant characteristics
Anaplasia
rapid growth
local invasion
metastatic potential
Invasive tumor lobules push downward from the
overlying epidermis and detached tumor islands
are noted within the dermis
Both cytoplasmic and cystic keratinization may
be observed.
The degree of keratinocyte differentiation within
these tumors is variable and an important
prognostic factor.
Verrucous carcinoma
is an indolent, well-differentiated squamous cell
carcinoma
grows slowly as an exophytic, cauliflower-like
lesion
may be associated with human papilloma virus
infection
This may arise in the anogenital region
(Buschke-Lowenstein tumor)
oral cavity (oral florid papillomatosis)
on the plantar surface of the foot (epithelioma
cuniculatum)
Spindle cell carcinoma
a rare subtype of squamous cell carcinoma
usually develops in sun-exposed areas in lightly-pigmented individuals older than 40 years of age.
The prognosis primarily depends on the depth of invasion
Verrucous and spindle cell carcinomas are managed similar to more conventional squamous cell carcinomas.
subtypes associated with clinically aggressive
behavior
adenoid (pseudoglandular)
Acantholytic
Adenosquamous
desmoplastic squamous cell carcinoma.
A careful history
should include questions regarding patient risk
factors
personal and family history of skin cancer
UV exposure history,
history of ionizing radiation therapy
occupational exposures
immunosuppression
Slowly enlarging growth on or just beneath the
skin surface
History of sore that will not completely heal
Bleeding or pain unusual
Paresthesia and formication in case of perineural
spread (3-14%)
Site, size, mobility of the primary lesion should be documented
Evidence of PNI is assessed
Any features of cartilage or bone invasion should be examined
Complete skin examination should be done
Regional lymph nodes
Typical lesions are round-to-irregular, plaquelike
nodular, and overlaid with a warty keratoticscale or conical keratinized cutaneous horn.
Surrounding erythema may be present, and bleeding results from minimal trauma
usually superficial, invasion of the subcutis does occur with muscle invasion and extension along periosteal, perineural, and angiolymphaticchannels.
Biopsy should be performed before deciding on
treatment
Small lesion occurring on free skin areas ( not
involving eye lid, ear or periorbital areas ) can
undergo biopsy and simultaneous excision
Larger lesion or those involving areas where
cosmetic or functional deficit will occur with
excision
Incisional biopsy or punch biopsy
Biopsy should include deep reticular dermis
This is preferred because infiltrative pathology
may be found only in deep tissues
Superficial biopsy will frequently miss this
Done in extensive disease such as
bone involvement
PNI
deep soft tissue involvement
lymphovascular invasion is suspected
In the case of carcinomas involving the medial or
lateral canthi of the eyes
one should consider obtaining either a (CT) or
(MRI) scanto assess the depth of invasion
because apparently superficial cancers
sometimes extend along the wall of the orbit
CT Scan is done to role out bone and cartilage
invasion
Lymph node status can also be assessed
MRI preferred over CT when PNI is suspected
Clinically or radiologically if lymph node present
Proceed with fnac
If negative repeat fnac or excision biopsy of node
SURGERY
RADIOTHERAPY
offer equivalent excellent cure rates of 90% to 95%
treatment approach must be individualized based on specific risk factors and patient characteristics for the most acceptable cosmetic and functional outcome.
The management of skin cancer is guided by the
biologic and histologic nature of the tumor, the
anatomic site, the underlying medical status of
the patient
It is desirable to avoid RT in young patients
Late effect of RT progress with time
Localized scc are most commonly treated with surgery
Curettage with electrodesiccation is the alternatively scraping away the tumor tissue with a curette down to a firm layer of normal dermis and denaturing the area with electrodessication
It is fast and cost effective
Margin cannot be assessed
Curettage with electrodesiccation reserved for
actinic keratoses (AKs), and SCC in situ without follicular involvement located on the trunk or extremities
but are contraindicated in deeply infiltrating lesions
Wound contracture may cause tissue distortion and impaired cosmesis
Cure rate is about 90-95% for low risk tumors
Recurrence rate high about 20-25% for high risk features
EXCISION WITH POST OP MARGIN
ASSESSMENT (POMA)
Standard surgical excision followed by post op
pathological evaluation of margins
For low risk tumors < 2 cm – 4-6mm margin
For high risk tumors higher margins are required
Mohs surgery or excision with intra operative
frozen section assessment
Preferred technique for high risk scc
Mohs' micrographic surgery
involves fixation of tumor to enable tumor
mapping and surgical excision with multiple
frozen sections taken until microscopically clear.
Cosmesis, often poor just after the procedure,
improves with time.
A key defining feature of MMS is that the
surgeon excises, maps, and reviews the
specimen personally, minimizing the chance of
error in tissue interpretation and orientation
This technique is employed for BCC and SCC in
embryonic fusion zones
recurrent or deeply invasive lesions
tumors with potential for diffuse lateral spread or
perineural invasion
Although surgery is main treatment for nmsc
Patient preference and other factor may lead to
choice of RT
early skin cancer of eyelid, external ear ,or nose
may result in significant cosmetic deformity and
necessitates complex reconstructions
Elderly patients who are not fit for surgery
Patients with PNI with gross tumor extending to
the sites which makes lesion unresectable
Such lesions are treated with RT alone
positive surgical margins
perineural invasion
invasion of bone, cartilage, and skeletal muscle
Cure rates lower
Reserved where surgery or radiotherapy is
contraindicated or impractical
Cryotherapy , topical 5 FU, imiquimod, Photo
dynamic therapy
immune-response modifier that promotes a cell-
mediated immune response
through induction of cytokine production,
particularly interferon @ and b and interleukin-
12.
treatment of Aks, scc insitu and superficial BCCs
on the trunk, neck, or extremities
PDT involves application of photo sensitizing
agent on skin followed by irradiation with light
source
Used for premalignant or low risk superficial on
face and scalp
exposes skin cancers to destructive subzero
temperatures.
Heat transfer occurs from the skin, which acts as a
heat sink.
Tissue damage is caused by direct effects initially
subsequently by vascular stasis, ice crystal
formation, cell membrane disruption, pH changes,
hypertonic damage, and thermal shock
inability to evaluate thoroughness of tumor
eradication.
The absence of margin
control
development of dense scar, which might obscure
recurrence
Involvement increase the chance of recurrence
and mortality
Associated with PNI, LVI, poor differentiation
Lymph node dissection followed by adjuvant RT
Cervical node
Neck dissection alone if only one involved
If 2 or more or ECE neck dissection followed by
RT
Metastatic to parotid node is common if cervical lymph nodes are involved (60-80%)
Superficial or total parotidectomy followed by RT
If inoperable parotid node – high dose preop RT 60-70 Gy followed by parotidectomy
20 % decrease in local recurrence with addition of RT
5 YR survival also increased by 15-20%
EBRT
Ortho voltage x rays
Electron beam
High energy x rays
OR
INTERSTITIAL IMPLANT
100- 250 Kvp
Most early skin cancer can be treated
Advantages
Maximum dose at skin surface, no bolus
required
Less beam constriction both at surface and at
deapth so smaller field can be used
Shielding of eye is easier
DISADVANTAGES
Higher dose to deeper tissues and to underlying
bone and cartilage
It is unavailable in most RT Dept.
It is usually used for treatment of scalp lesion
inorder to reduce dose to brain
If tumor is located near eye – gold plated lead
eye shield is directly placed over anaesthetised
cornea
Advanced skin cancer that are deeply invasive
are often treated with higher energy
To adequately cover the deeper tissue
Bolus is kept to ensure the adequate surface
dose
Field arrangement may vary depending on sites
Wedge pair technique – external ear
3 field technique- lesion extending along 5 th
nerve
Even IMRT can be used when we have to treat
till base of skull in case of PN
Proper immobilization to ensure consistent
delivery of treatment is essential
primary skin collimation with custom lead cutouts
can also be used to define the field in case of
electrons
To minimize normal-tissue toxicity, underlying
structures such as the lens, cornea, nasal
septum, and teeth should be protected by
placing a lead shield under the eyelids over or in
the nasal cavity or under the lips
The margin of normal-feeling tissue included in
the target volume is usually 0.5 to 1.0 cm for skin
cancers of 2.0 cm
1.5 to 2.0 cm for larger cancers.
At least a 0.5-cm margin on the suspected depth
of invasion should be included in the target
volume
Wider margin while using electrons
Sequelae of Radiation Therapy
Moist desquamation
The skin in the radiation field may gradually become telangiectatic, atrophic, and hypopigmented over a period of years and is more sensitive to trauma.
healing may be delayed after surgery on an irradiated region.
Hair loss and a loss of sweat gland function are usually permanent
Ectropion and epiphora may develop after the
treatment of eyelid carcinomas (particularly ones
involving the lower eyelid)
The incidence of soft tissue necrosis is typically
less than 3%.
Osteoradionecrosis occurs in approximately 1%
of patients
radiochondritis is rare
3-4 % of scc can have distant metastases
Systemic chemotherapy
Platinum based chemotherapy
Interferon @ or cis- retinoic acid
Cetuximab and gefitinib is also tried