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