Skin Cancers

Martin LeBlanc, MD FRCSCAssistant Professor

Dalhousie University

Plastic Surgery

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What are the three common

encountered types of skin

cancers?

Non-melanoma skin cancers are the

most common malignancy worldwide

99% are basal cell carcinomas (BCCs)

and squamous cell carcinomas (SCCs)

of skin

Objectives

Learn about etiology, classification and treatment options for common skin cancers including BCC, SCC, and MELANOMA

Learn risk factors associated with recurrence and metastasis of these malignancies, and how to optimize patient management and surveillance

Anatomy

2 Layers:

Epidermis

Dermis

What some of the functions

of the skin?

Function of Skin

Sensory organ

Barrier to moisture loss

Barrier to trauma

Thermoregulation

Immune defense

Vitamin D production

UV protection

Which is the most and least

common type of skin

cancer?

Other much less common

forms of NMSC include:

Merkel cell carcinoma (MCC)

Primary cutaneous B-cell lymphoma

Kaposi sarcoma

Carcinosarcoma

Dermatofibrosarcoma

What will you ask on

History?

What will you look for on

Physical Examination?

What investigations will you

order?

Basal Cell Carcinoma

Epidemiology

Most common skin CA worldwide

Accounts for 75% of skin cancers

95% of cases occur between 40-79 years of age

Incidence increasing

Age of dx decreasing (early detection/awareness/surveillance)

Caucasians most affected

3-5 times more common than SCC

Risk Factors

Chronic sunlight exposure

Exposed areas of body

Face, ears, neck, scalp, shoulders, back

UV light exposure (cumulative)

Ionizing radiation

Chemicals

Immunosuppression: HIV, transplant meds

Skin type/ethnicity

Caucasian; Fitzpatrick I, II

Syndromes and genetic disorders

Fitzpatrick’s Classification of skin types

Skin Type Color Reaction to first sun exposure

I White Always burn, never tan

II White Usually burn, tan with difficulty

III White Sometimes mild burn, tan average

IV Moderate brown Rarely burn, tan with ease

V Dark brown Very rarely burn, tan very easily

IV Black Does not burn, tan very easily

Histology

Arises from the basal layer of the epidermis

Cell of origin: basal keratinocyte

- pluripotent epithelial cell found in follicles at dermo epidermal junction

Clinical Appearance

Classic appearance:

Raised border

Pearly central area

Associated telangiectasias

Scaly

May have areas of ulceration or scarring

“rodent ulcer”

BCC Treatment Options

Surgical excision

Electrodessication & Curettage (EDC)

Chemotherapy

topical, intra-lesional, systemic

Radiation therapy

Cryosurgery

Surgical Margins for Primary Excision of BCC

NO UNIFORM RECOMMENDATION regarding margin size

3-5 mm for small well-circumscribed lesions

1 cm for larger, more aggressive variants

Treatment of Basal Cell Cancer

Mohs micrographic surgery:

Frozen section

Examine margins in 3 planes.

Expensive

Time consuming

Cure rates approach 100%*

Recurrence, Metastasis and Follow-up

Recurrence rates:

Primary tumor: 0-9%

New tumor: up to 47%

Metastatic BCC:

Risk

Squamous Cell Cancer

Epidemiology & Etiology

Second most common skin CA

Cell of origin: Malpighian cell

Found in basal layer of epidermis

Metastasis in 5%

Risk Factors

UV light exposure

Sunlight (UVB>UVA)

PUVA in psoriasis patients

Fitzpatrick skin type

Age

Ionizing radiation

Immunosuppression

Chemotherapeutics, transplant drugs

Risk Factors

Chronic ulceration

osteomyelitis, burns, discoid lupus, fistula tracts (e.g. hidradenitis suppurativa, pilonidal disease)

Viruses

HPV

Epidermodysplasia verruciformis

HSV

Risk Factors

Precursor Lesions*

Actinic keratoses (AK) & cheilitis

Keratoacanthoma

Bowen’s disease

Actinic Keratosis

Red-brown macule/papule/plaque

Dry and scaly

Often more palpable than visible

Found in sun-exposed areas

Face, ears, neck, scalp, chest, upper limb

Actinic cheilitis

Aggressive variant of AK that occurs on lips

Actinic Keratosis

5-20% develop into SCC

Actinic Keratosis

Treatment indicated due to risk of malignant degeneration

Close observation

Cryosurgery

Electrodessication & curettage

Aldara (5%)

Efudex

Diclofenac/hyaluronic acid gel

SCC Physical Examination

Lymph node examination mandatory

WHY?

SCC Physical Examination

Nodule or plaque

Variable degree of scale, crust, erosion, ulceration

Pink, tan or a combination

May appear white in moist anatomic sites such as skinfolds, mucosa

Lymph node examination mandatory

Treatment of Squamous Cell Cancer

Surgical excision (NCCN Guidelines)

Lesion < 2 cm, grade 1, low-risk lesion: 4-6 mm margin

Lesion > 2cm, grade 2,3,4, to subq fat: 10 mm margin

Margin lies OUTSIDE area of peripheral erythema

Mohs micrographic surgery

Radiation*

Cryosurgery

Electrodessication & curettage

Chemotherapy (Efudex, Aldara)

ALL of these protocols for treatment are the SAMEas for BCC

Outcome of Squamous Cell Cancer

Recurrence rate (average, all types)- 5-6%

Risk Factors for Recurrence

Long Duration

High-risk area

Large size

Poorly differentiated

Neglected

Recurrent

Radiation exposure

Metastatic Disease

Metastatic rate varies with etiology, location, primary vs. recurrent lesion

3% of lesions related to sun exposure

20-50% of lesions arising in scars, osteomyelitis (Marjolin’s ulcer)

85% occur in LNs; 15% to viscera

Most common sites: bone, brain, lung

5 year survival of patient with mets: 25%

Goals for BCC & SCC

Surgical excision

Evaluate margins

Re-excision if positive margins

95% cure rate for primary lesions

ALL patients need education regarding sun protection and self-examination of skin at each office or clinic visit

Prevention

Primary prevention

Behavioral changes to reduce sun

exposure

Reinforce the use of adequate sun

protection

Discourage intensive tanning

Prevention

Secondary prevention

Facilitate early detection

Screening of high-risk populations

Skin self-examination

Physician surveillance

Diagnosis and Types of

Biopsy Techniques

Gold standard for diagnosing NMSC

includes a thorough physical

examination

Conventional biopsy of the lesion for

histopathologic examination

A thorough lymph node exam is

essential for diagnosis of SCC due to

the risk for metastasis

Imaging

Majority of NMSCs can be successfully

managed without imaging

Bony invasion concerns = CT scan

Soft tissue or perineural involvement,

may necessitate MRI

PET-CT if metastasis

Chemotherapy

Role in the management of advanced

NMSC.

The term “advanced NMSC” usually

refers to metastatic disease and/or

inoperable lesions

Immunotherapy

BCC

The Hedgehog Pathway Inhibitors

Vismodegib and Sonidegib are SHH

inhibitors approved for treatment of

advanced BCC

Immunotherapy

SCC

Epidermal growth factor receptor

(EGFR) appears to be involved in the

pathogenesis of SCC

Its inhibitors, such as cetuximab and

panitumumab may be used in the

treatment of SCC

Melanoma

Introduction

In past 30 years, incidence in US has

doubled

Melanoma accounts for 4% of all skin

cancers

However, responsible for 80% of skin

cancer-related deaths

Introduction

Caucasian North American lifetime risk

is 1.4%

General population risk 0.5%

Risk Factors

1. UV exposure

2. Age

3. Family History

4. Phenotype

5. Gender

6. Race

7. Immunosuppression

Clinical Presentation

American Cancer

Society ABCD’s of melanoma

Asymmetric

Border irregularity

Color variability

Diameter > 6mm.

Clinical Presentation

Be suspicious of lesions that change in

size*

color*

elevation

Pruritis

Bleeding

Ulceration

Clinical Presentation

Region

Women lower limbs

Men Trunk

1% arise from preexisting nevi

Approach to suspicious lesions

Clinical Diagnosis

Management

Excise- changing lesions, atypical lesions

Routine self and physician exam

Approach to suspicious lesions

Accuracy of clinical diagnosis:

48-81%

Biopsy Technique:

Suspicious lesions should be biopsied

5-7 mm punch OK; may miss thickest portion

Excisional biopsy for lesions

Superficial Spreading Melanoma

Nodular Melanoma

Lentigo Maligna Melanoma

Acral Lentiginous Melanoma

Desmoplastic Melanoma

Amelanotic Melanoma

Ocular Melanoma

Classification

Depth of invasion of melanoma into dermis has been shown to be most powerful determinant of outcome

Breslow Thickness:

Measurement of tumor thickness in millimeters

Prognosis: Tumor Histology

Thickness:

- Most important determinant of survival for pts with stage I/II

- Tumors < 0.76 mm 10-year survival 92%

- Tumors > 3 mm thick 10-year survival 50%

Prognosis: Tumor Histology

The 5-year relative survival rate from

diagnosis for localized, early melanoma

is over 98%

However, less than 20% for melanoma

that has spread to distant sites

https://seer.cancer.gov/statfacts/html/melan.html

Treatment: Surgical Margins

Wide local excision (WLE) with surgical

margins based on tumor thickness

In situ: 0.5 cm margin

Less than 1 mm: 1 cm margin

1-4 mm: 2 cm margin

Greater than 4 mm: 2-3 cm margin

Treatment: Surgical Margins

Primary CM treatment

recommendations are based on the

clinical measurement of surgical

margins around the tumor and not on

histologically measured peripheral or

deep margins

When a clear margin is narrow, it may

be necessary for closer monitoring

Treatment:

Sentinel lymph node biopsy

Staging procedure, not a therapeutic

treatment

Performed in conjunction with WLE of tumor

Sentinel lymph node biopsy

Indications

Melanomas > 1.0 mm

Sappey’s lines

Sentinel lymph node biopsy

SLN status is single most important predictor of survival in melanoma

It identifies two groups:

1) Those with a favorable prognosis requiring no additional treatment

2) High risk patients who might benefit from additional surgery (completion lymphadenectomy) and systemic therapy

Treatment:

Therapeutic lymph node dissection

Performed for positive SLNB or clinically palpable disease

Only potential cure for metastatic nodal disease

Treatment:

Therapeutic lymph node dissection

Purpose of completion lymphadenectomy

for pts with regional lymph node

metastasis is:

(i) Achieve control of lymph node basin

(ii) Provide staging for adjuvant therapy

(iii) Achieve cure

Treatment:

Adjuvant Therapy

More effective against subclinical micro

metastasis than primary tumors, and against

residual disease after removal of gross disease

May benefit pts by palliation of symptoms,

prolongation of life

Treatment:

Adjuvant Therapy

Improved survival is demonstrated in

patients with advanced CM with use of

immune checkpoint blockade and

therapies targeting the mitogen-

activated protein kinase (MAPK)

pathway

These agents have shown a survival

advantage in the adjuvant setting for

SLN-node positive patients

Treatment:

Adjuvant Therapy

Radiation therapy has a limited role in melanoma treatment, but may be used in rare instances as adjuvant therapy and in certain cases for palliation

Surveillance Guidelines

Goal of any melanoma follow-up is the early

detection and treatment of recurrent or residual

disease

Local recurrence usually occurs within 5 cm of

original lesion within 3-5 years, usually resulting

from incomplete resection of primary tumor

Reports of second primary melanomas is 2-3.4%

Surveillance Guidelines

Special test are reserved for pts who have signs or symptoms referring to specific organ system

One study showed no impact on survival with CXR and LFTs

One study showed that only 6% of recurrent lesions were first detected by CXR; the other 94% were identified by the patient, through Hx or physical examination

Abnormal lab studies in one study were present in 11% but were never the only indicator of recurrence

Melanoma: Distant Metastases

Median survival after diagnosis of distant metastases is ~ 6 months

5 year survival is ~ 6%

Usually metastasizes first to skin, subcutaneous tissues, and lymph node, followed by lungs, liver, brain, bone, and intestines

THE END