Squamous cell carcinoma (SCC) is a common form of skin cancer that arises from the squamous cells—flat cells located in the outer part of the epidermis. Though often considered less aggressive than melanoma, squamous cell carcinoma can become dangerous if left untreated, potentially invading deeper layers of the skin and even spreading to other organs.
This comprehensive guide explores every aspect of squamous cell carcinoma, including risk factors, early warning signs, treatment options, and strategies for prevention.
Understanding Squamous Cell Carcinoma
Squamous cell carcinoma originates in the squamous epithelium, the thin, flat cells that make up the outermost layer of the skin. SCC can also occur in mucous membranes and internal organs lined with squamous cells, such as the mouth, throat, lungs, and cervix. However, cutaneous (skin-related) SCC is by far the most prevalent type.
While it’s typically slow-growing, SCC has the potential to invade underlying tissues, disfigure affected areas, and metastasize if not detected and managed early.
Common Causes and Risk Factors
1. Prolonged UV Exposure
The leading cause of squamous cell carcinoma is long-term exposure to ultraviolet (UV) radiation, either from the sun or artificial sources such as tanning beds. UV rays damage DNA in skin cells, leading to abnormal growth and cancerous mutations.
2. Fair Skin and Light Eyes
Individuals with fair complexions, blonde or red hair, and light-colored eyes have a higher risk due to less melanin protection against UV damage.
3. Age and Gender
SCC is more common in older adults, particularly men, due to cumulative sun exposure over time.
4. Immunosuppression
People with weakened immune systems—such as organ transplant recipients or HIV patients—are at greater risk of developing aggressive forms of SCC.
5. History of Skin Cancer or Precancerous Lesions
Having had actinic keratosis, basal cell carcinoma, or previous SCC significantly increases recurrence risk.
6. Exposure to Carcinogens
Prolonged contact with arsenic, tar, or industrial chemicals can increase the likelihood of developing SCC.
Signs and Symptoms of Squamous Cell Carcinoma
SCC may appear on sun-exposed areas like the face, ears, neck, lips, scalp, hands, and arms, but can also develop in non-sun-exposed areas.
Typical Features Include:
- Scaly red patches with a rough surface
- Open sores that do not heal or heal and return
- Raised growths with a central depression
- Thickened or wart-like skin
- Bleeding or crusting lesions
- Painful or tender growths
Early detection is critical. Any lesion that changes in size, shape, color, or texture should be evaluated by a dermatologist immediately.
Diagnosis of Squamous Cell Carcinoma
A clinical diagnosis usually begins with a visual examination and dermoscopy, followed by biopsy to confirm the diagnosis.
Diagnostic Procedures Include:
- Shave biopsy: Removing a small part of the lesion
- Punch biopsy: Taking a deeper skin sample
- Excisional biopsy: Removing the entire suspected growth for analysis
In cases of suspected metastasis, imaging studies such as CT scans, MRI, or PET scans may be used.
Staging of Squamous Cell Carcinoma
Staging helps determine the extent of spread and guides treatment planning.
- Stage 0 (in situ): Cancer is confined to the top layer of skin
- Stage I-II: Cancer has grown into deeper layers but has not spread
- Stage III: Cancer has spread to nearby lymph nodes or tissues
- Stage IV: Cancer has metastasized to distant organs
Tumor depth, location, immunosuppression status, and histological features impact staging.
Treatment Options for Squamous Cell Carcinoma
1. Surgical Excision
The most common treatment. The tumor and a margin of healthy tissue are surgically removed.
2. Mohs Micrographic Surgery
This technique is highly effective for SCC in sensitive areas like the face. It involves removing the cancer layer by layer while preserving healthy tissue.
3. Cryotherapy
Liquid nitrogen is used to freeze and destroy abnormal tissue. Suitable for small, superficial SCCs.
4. Curettage and Electrodessication
The tumor is scraped off, and the base is cauterized with an electric needle. Used for small, low-risk SCCs.
5. Radiation Therapy
Often used for patients who cannot undergo surgery. Especially useful for older adults or hard-to-reach tumors.
6. Topical Chemotherapy
Agents such as 5-fluorouracil (5-FU) or imiquimod may be applied to treat superficial SCCs.
7. Systemic Therapies
For advanced or metastatic SCC, options include:
- Immunotherapy (e.g., Cemiplimab, a PD-1 inhibitor)
- Chemotherapy (e.g., cisplatin or 5-FU)
- Targeted therapy for tumors with specific mutations
Prognosis and Survival Rates
When detected early, squamous cell carcinoma has an excellent prognosis, with a 5-year survival rate of over 95%. However, advanced or neglected SCC may spread and require more aggressive treatment, reducing survival rates.
Prevention Strategies for Squamous Cell Carcinoma
1. Avoid Prolonged Sun Exposure
Limit outdoor activity during peak UV hours (10 a.m. – 4 p.m.).
2. Use Broad-Spectrum Sunscreen
Apply SPF 30 or higher every day, even on cloudy days. Reapply every two hours.
3. Wear Protective Clothing
Use wide-brimmed hats, UV-blocking sunglasses, and long-sleeved clothing when outdoors.
4. Avoid Indoor Tanning
Tanning beds emit concentrated UV radiation and dramatically increase skin cancer risk.
5. Regular Skin Examinations
Perform monthly self-exams and schedule annual dermatological screenings. Early detection saves lives.
Living with and After Squamous Cell Carcinoma
Post-Treatment Monitoring
Regular follow-up appointments are crucial to detect recurrence or new lesions. Patients with a history of SCC should undergo skin checks every 3–6 months for the first two years.
Lifestyle Adjustments
- Maintain a healthy diet rich in antioxidants
- Stay hydrated and active
- Protect skin daily
- Be vigilant for any new or changing lesions
Conclusion
Squamous cell carcinoma is a highly treatable skin cancer when diagnosed early. With vigilant sun protection, routine screenings, and prompt medical care, individuals can reduce their risk and manage their skin health effectively. Understanding the causes, recognizing the symptoms, and acting swiftly are the best defenses against SCC’s progression.
