Overview

Skin cancer encompasses a group of malignancies that originate in the skin cells. It is the most frequently diagnosed cancer worldwide, with over 5 million cases treated annually in the United States alone. The disease develops when DNA damage to skin cells, most often caused by ultraviolet (UV) radiation from the sun or tanning beds, triggers mutations that lead to uncontrolled cell multiplication.

There are three main types of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. BCC and SCC, collectively known as non-melanoma skin cancers, account for the vast majority of cases and are generally highly treatable when caught early. Melanoma, while less common, is significantly more dangerous due to its tendency to spread to other parts of the body if not detected and treated promptly.

The incidence of skin cancer has been rising steadily over the past several decades, attributed to increased sun exposure, tanning bed use, and improved detection methods. While anyone can develop skin cancer, certain factors such as fair skin, history of sunburns, excessive sun exposure, and family history increase risk. Early detection through regular skin examinations and prompt treatment are crucial for optimal outcomes, with cure rates exceeding 95% for early-stage disease.

Symptoms

Skin cancer symptoms vary depending on the type and location of the cancer. The key to early detection is recognizing changes in your skin and seeking medical evaluation for any suspicious lesions.

Primary Warning Signs

The ABCDEs of Melanoma

  • A - Asymmetry: One half doesn't match the other half
  • B - Border: Irregular, scalloped, or poorly defined edges
  • C - Color: Varied colors including shades of brown, black, red, white, or blue
  • D - Diameter: Larger than 6mm (pencil eraser), though can be smaller
  • E - Evolving: Changes in size, shape, color, or symptoms

Basal Cell Carcinoma Signs

  • Pearly or waxy bump on sun-exposed areas
  • Flat, flesh-colored or brown scar-like lesion
  • Bleeding or scabbing sore that heals and returns
  • Pink growth with elevated rolled border
  • Shiny nodule that may have visible blood vessels

Squamous Cell Carcinoma Signs

  • Firm, red nodule on sun-exposed skin
  • Flat lesion with scaly, crusted surface
  • New sore or raised area on old scar
  • Rough, scaly patch on lip
  • Red sore or rough patch inside mouth
  • Wart-like growth

Causes

Skin cancer develops when mutations occur in the DNA of skin cells, causing them to grow out of control. While multiple factors can contribute to these mutations, ultraviolet radiation is the primary culprit.

Primary Causes

  • Ultraviolet (UV) radiation - From sun exposure and tanning beds, damages DNA in skin cells
  • Cumulative sun exposure - Lifetime exposure increases risk, especially for BCC and SCC
  • Severe sunburns - Particularly blistering sunburns in childhood and adolescence
  • Tanning bed use - Artificial UV radiation significantly increases melanoma risk

Contributing Factors

  • Genetic mutations - Inherited conditions like xeroderma pigmentosum
  • Chemical exposure - Arsenic, tar, and certain pesticides
  • Radiation therapy - Previous treatment for other cancers
  • Chronic inflammation - Long-standing wounds or burns
  • Human papillomavirus (HPV) - Certain strains linked to SCC
  • Immunosuppression - Medications or conditions weakening immune system

Cellular Mechanisms

  • DNA damage - UV radiation creates thymine dimers and other mutations
  • Tumor suppressor gene inactivation - Loss of p53 function
  • Oncogene activation - Mutations in RAS, BRAF genes
  • Defective DNA repair - Inability to fix UV-induced damage
  • Apoptosis evasion - Damaged cells avoid programmed death

Risk Factors

Understanding your risk factors for skin cancer helps guide prevention strategies and screening frequency. Some factors are modifiable, while others are inherent characteristics.

Major Risk Factors

  • Fair skin - Less melanin provides less UV protection
  • History of sunburns - Even one blistering sunburn doubles melanoma risk
  • Excessive sun exposure - Occupational or recreational
  • Tanning bed use - Increases melanoma risk by 75% if used before age 35
  • Moles - Having many moles or atypical moles
  • Family history - 10% of melanomas run in families
  • Personal history - Previous skin cancer increases risk

Additional Risk Factors

  • Age - Risk increases with age, though melanoma affects younger people too
  • Male gender - Men have higher rates, possibly due to sun exposure patterns
  • Immunosuppression - Organ transplant recipients, HIV/AIDS patients
  • Certain genetic conditions - Albinism, xeroderma pigmentosum
  • Previous radiation therapy - Increased risk in treated areas
  • Chemical exposure - Occupational exposure to carcinogens
  • Chronic skin conditions - Some inflammatory conditions

Geographic and Environmental Factors

  • Living near equator - Higher UV exposure
  • High altitude - Thinner atmosphere, more UV radiation
  • Sunny climate - Year-round sun exposure
  • Reflective surfaces - Snow, water, sand increase UV exposure
  • Ozone depletion - Reduced atmospheric protection

Diagnosis

Early and accurate diagnosis of skin cancer is crucial for successful treatment. The diagnostic process typically involves visual examination, dermoscopy, and tissue confirmation through biopsy.

Clinical Examination

  • Visual inspection - Systematic examination of entire skin surface
  • Medical history - Sun exposure, tanning, family history, previous lesions
  • Palpation - Feeling lesions for texture, mobility, depth
  • Lymph node examination - Checking for spread in advanced cases
  • Photography - Documenting lesions for monitoring changes

Dermoscopy

Non-invasive examination using magnification and polarized light:

  • 10-30x magnification reveals subsurface structures
  • Pattern analysis helps differentiate benign from malignant
  • Digital dermoscopy allows comparison over time
  • Improves diagnostic accuracy by 20-30%

Biopsy Types

  • Shave biopsy - Superficial lesions, quick procedure
  • Punch biopsy - Full-thickness sample, 2-6mm diameter
  • Excisional biopsy - Complete removal with margins
  • Incisional biopsy - Part of large lesion sampled
  • Fine needle aspiration - For lymph nodes or deep lesions

Pathological Analysis

  • Histopathology - Microscopic examination of tissue
  • Immunohistochemistry - Special stains for cell markers
  • Breslow thickness - Melanoma depth measurement
  • Clark level - Anatomic depth of invasion
  • Mitotic rate - Cell division frequency
  • Margin assessment - Checking if all cancer removed

Staging Investigations

For advanced cases, especially melanoma:

  • Sentinel lymph node biopsy - First draining node tested
  • CT scan - Chest, abdomen, pelvis for metastases
  • PET scan - Whole-body metabolic imaging
  • MRI brain - For high-risk melanoma
  • Blood tests - LDH, liver function tests
  • Molecular testing - BRAF, KIT mutations for treatment planning

Treatment Options

Treatment for skin cancer depends on the type, size, location, and stage of the cancer, as well as the patient's overall health. Most skin cancers are highly treatable when caught early.

Surgical Treatments

Standard Excision

  • Removal of tumor with margin of healthy tissue
  • Margins vary by cancer type (4-5mm for BCC, 4-6mm for SCC, 1-2cm for melanoma)
  • Sutured closure or skin graft/flap for larger defects
  • Cure rates over 95% for primary BCC and SCC

Mohs Micrographic Surgery

  • Layer-by-layer removal with immediate microscopic examination
  • Highest cure rate (up to 99%) while preserving healthy tissue
  • Ideal for facial lesions, recurrent cancers, ill-defined borders
  • Same-day reconstruction possible

Destructive Treatments

  • Cryotherapy - Liquid nitrogen freezing for superficial lesions
  • Electrodesiccation and curettage - Scraping and burning
  • Laser therapy - CO2 or pulsed dye laser ablation
  • Photodynamic therapy - Light-activated drug treatment

Topical Treatments

  • 5-Fluorouracil (5-FU) - Chemotherapy cream for superficial BCC/SCC
  • Imiquimod - Immune response modifier
  • Diclofenac gel - For actinic keratoses
  • Ingenol mebutate - Plant-derived treatment
  • Tretinoin - For pre-cancerous lesions

Radiation Therapy

  • Primary treatment for inoperable tumors
  • Adjuvant therapy after surgery for high-risk features
  • Palliative treatment for advanced disease
  • Electronic brachytherapy for superficial lesions
  • Stereotactic radiosurgery for brain metastases

Systemic Therapies

For Advanced Melanoma:

  • Immunotherapy - Checkpoint inhibitors (pembrolizumab, nivolumab, ipilimumab)
  • Targeted therapy - BRAF/MEK inhibitors for BRAF-mutant melanoma
  • Chemotherapy - Dacarbazine, temozolomide (less commonly used)
  • Interleukin-2 - High-dose for select patients
  • Oncolytic virus therapy - T-VEC for injectable lesions

For Advanced BCC/SCC:

  • Hedgehog inhibitors - Vismodegib, sonidegib for advanced BCC
  • PD-1 inhibitors - Cemiplimab for advanced SCC
  • EGFR inhibitors - Cetuximab for unresectable SCC
  • Chemotherapy - Cisplatin-based regimens

Follow-up Care

  • Regular skin examinations (frequency based on risk)
  • Self-examination monthly
  • Sun protection counseling
  • Photography for mole monitoring
  • Blood work and imaging for advanced disease

Prevention

Most skin cancers are preventable through sun protection and avoiding artificial UV sources. Prevention strategies should begin in childhood and continue throughout life.

Sun Protection Measures

  • Sunscreen use - SPF 30+ broad-spectrum, reapply every 2 hours
  • Protective clothing - Long sleeves, pants, wide-brimmed hats
  • Seek shade - Especially between 10 AM and 4 PM
  • Sunglasses - UV-blocking to protect eyes and surrounding skin
  • Avoid tanning beds - No safe level of artificial tanning
  • Window protection - UV-blocking film for cars and homes

Behavioral Strategies

  • Check UV index daily and plan activities accordingly
  • Use extra caution near water, snow, and sand
  • Protect children - 80% of lifetime sun exposure occurs before age 18
  • Be aware of medication photosensitivity
  • Avoid sunburns at all costs
  • Don't use sunscreen to extend sun exposure time

Early Detection

  • Monthly self-examinations - Check entire body systematically
  • Partner checks - For hard-to-see areas
  • Annual dermatology visits - Professional skin examinations
  • Photography - Document moles for comparison
  • Know your skin - Be aware of normal marks and changes

High-Risk Group Recommendations

  • More frequent dermatology visits (every 3-6 months)
  • Total body photography at specialized centers
  • Genetic counseling for familial melanoma
  • Extra vigilance with immunosuppressive medications
  • Consider vitamin D supplementation due to sun avoidance

Community Prevention

  • School sun safety programs
  • Workplace sun protection policies
  • Shade structures in public spaces
  • Ban on tanning beds for minors
  • Public education campaigns

When to See a Doctor

Early detection dramatically improves skin cancer outcomes. Don't delay seeking medical attention for suspicious skin changes.

Seek Immediate Evaluation For:

  • Any new growth that appears and grows rapidly
  • A mole that changes in size, shape, or color
  • A lesion that bleeds, crusts, or doesn't heal within 4 weeks
  • Any spot that looks different from your other spots
  • A mole with irregular borders or multiple colors
  • Any lesion that itches, tingles, or hurts persistently

Schedule Regular Screening If You Have:

  • Fair skin, light eyes, or red/blonde hair
  • History of blistering sunburns
  • Family history of melanoma
  • More than 50 moles
  • Atypical or dysplastic moles
  • Previous skin cancer
  • Weakened immune system
  • Significant sun exposure history

Warning Signs Requiring Urgent Care:

  • Rapid growth of a pigmented lesion
  • Ulceration or bleeding from a mole
  • Satellite lesions around a primary spot
  • Swollen lymph nodes near a suspicious lesion
  • Multiple new lesions appearing quickly
  • Return of a previously removed cancer

Related Conditions

Several conditions may be related to or mistaken for skin cancer:

References

  1. Siegel RL, et al. (2023). Cancer Statistics, 2023. CA: A Cancer Journal for Clinicians.
  2. National Comprehensive Cancer Network. (2023). NCCN Clinical Practice Guidelines in Oncology: Melanoma.
  3. American Academy of Dermatology. (2023). Skin Cancer Resource Center.
  4. Swetter SM, et al. (2022). NCCN Guidelines Insights: Melanoma. J Natl Compr Canc Netw.
  5. WHO International Agency for Research on Cancer. (2023). Skin Cancer Statistics Worldwide.