BCC vs. SCC: Understanding the Two Most Common Skin Cancers

Two Cancers, Two Different Behaviors

Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) together account for the vast majority of all skin cancers diagnosed worldwide. While they share common risk factors, particularly ultraviolet radiation exposure, these two cancers differ significantly in how they look, how they grow, how they are treated, and the risks they pose if left unaddressed.

Understanding these differences is essential for recognizing warning signs on your own skin and making informed decisions about treatment. In Israel, where skin cancer rates rank among the highest globally, this knowledge is especially relevant.

Where Do They Come From?

Both BCC and SCC originate in the epidermis, the outermost layer of skin, but they arise from different cell types.

Basal cell carcinoma develops from basal cells, which sit at the deepest part of the epidermis and are responsible for generating new skin cells. When UV-induced DNA damage disrupts the normal growth cycle of these cells, BCC can develop.

Squamous cell carcinoma originates from squamous cells, which are the flat cells that form the surface of the skin. These cells are exposed to more direct environmental damage, and SCC often develops from precancerous lesions called actinic keratoses that accumulate from years of sun exposure.

Appearance: How to Tell Them Apart

One of the most practical ways to distinguish between BCC and SCC is by their visual characteristics, though definitive diagnosis always requires a biopsy.

Basal Cell Carcinoma Appearance - Pearly or translucent bump, often with visible tiny blood vessels - Flat, pinkish or flesh-colored patch that may resemble eczema - A sore that bleeds, crusts over, and then reopens in a recurring cycle - Waxy, scar-like area with indistinct borders (morpheaform variant) - Typically found on the face, neck, and ears

Squamous Cell Carcinoma Appearance - Rough, scaly red patch that may bleed when disturbed - Firm, raised nodule with a rough or wart-like surface - Open sore that persists for weeks without healing - Dome-shaped growth with a central ulcer or depression - Cutaneous horn, a hard, protruding projection of keratin - Found on the face, ears, scalp, lips, backs of hands, and forearms

While both cancers favor sun-exposed areas, SCC can also develop on areas of chronic scarring, inflammation, or previous radiation treatment.

Growth Rate and Behavior

The growth patterns of BCC and SCC differ in ways that have direct implications for treatment urgency.

BCC: Slow but Persistent Basal cell carcinoma is typically a slow-growing tumor. It may take months or even years for a BCC to become clinically noticeable. Most BCCs grow locally, gradually invading surrounding tissue, but they almost never metastasize to lymph nodes or distant organs. The metastasis rate for BCC is estimated at less than 0.1%.

However, slow growth does not mean BCC is harmless. If neglected, it can burrow deep into underlying tissues, eroding cartilage, bone, and nearby structures, particularly on the nose, ears, and around the eyes.

SCC: Faster and More Assertive Squamous cell carcinoma tends to grow more quickly than BCC and carries a meaningful risk of metastasis. Approximately 2-5% of SCCs will spread to regional lymph nodes or distant sites, with certain high-risk subtypes carrying even higher metastasis rates.

High-risk features that increase the danger of SCC include large tumor size (greater than 2cm), depth of invasion beyond 6mm, location on the ear or lip, poor histological differentiation, perineural invasion, and occurrence in immunosuppressed patients.

This difference in biological behavior means that while a dermatologist may monitor a very small, early-stage BCC for a short period before treatment, SCC typically demands more prompt intervention.

Risk Factors: Shared and Distinct

BCC and SCC share several key risk factors, but there are notable differences in how these factors contribute to each cancer.

Shared Risk Factors - Ultraviolet radiation exposure (the dominant risk factor for both) - Fair skin, light eyes, and light hair - Age over 50 - History of sunburns - Immunosuppression - Previous history of skin cancer

Factors More Strongly Associated with BCC - Intermittent, intense sun exposure (such as recreational sunburns) - Genetic conditions such as basal cell nevus syndrome (Gorlin syndrome) - Exposure to arsenic

Factors More Strongly Associated with SCC - Cumulative, chronic sun exposure over many years - Actinic keratoses (precancerous lesions) - Chronic wounds, scars, and areas of inflammation - Human papillomavirus (HPV) infection - Organ transplant immunosuppression (SCC risk increases 65-250 times)

Treatment: When Does Each Require Mohs Surgery?

Both BCC and SCC can be treated with a variety of methods, but the choice of treatment depends on the tumor's characteristics, location, and risk level.

Treatment Options for Both - **Mohs micrographic surgery**: real-time microscopic margin assessment for complete removal - **Standard surgical excision**: removal with predetermined safety margins - **Curettage and electrodesiccation**: scraping and cauterizing (for superficial, low-risk tumors only) - **Radiation therapy**: for patients who cannot undergo surgery - **Topical therapies**: for very superficial BCCs only (imiquimod, 5-fluorouracil)

When Mohs Surgery Is Recommended

Mohs surgery is the gold standard for both BCC and SCC in specific situations. It offers a 99% cure rate for primary BCC and a 97% cure rate for primary SCC.

For SCC specifically, Mohs is strongly recommended for any high-risk tumor, as the complete margin assessment ensures the best chance of preventing recurrence and metastasis.

Prognosis: What to Expect

BCC Prognosis The prognosis for BCC is excellent. With appropriate treatment, cure rates exceed 95% with standard excision and reach 99% with Mohs surgery. Because BCC almost never metastasizes, the primary concern is local tissue destruction and the risk of developing additional BCCs. Studies indicate that 40-50% of patients who have had one BCC will develop another within five years.

SCC Prognosis The prognosis for SCC is also very good when detected and treated early, with Mohs surgery achieving a 97% cure rate. However, the stakes are higher with SCC due to the metastatic potential. When SCC does metastasize, the five-year survival rate drops significantly, underscoring the importance of early detection and complete treatment.

Patients who have had one SCC should be monitored closely, typically every three to six months for the first two years, as they are at elevated risk for both additional SCCs and BCCs.

Why Early Detection Matters for Both

Regardless of the type, early detection transforms the treatment experience. A small, early-stage BCC or SCC can often be treated in a single office visit with Mohs surgery, resulting in a small wound that heals with minimal scarring. A neglected tumor, by contrast, may require extensive surgery, reconstruction, and in the case of advanced SCC, radiation or systemic therapy.

In Israel, where the incidence of BCC reaches 188 per 100,000 and SCC 58 per 100,000, regular skin cancer screenings are a vital preventive measure. Annual full-body skin checks with dermoscopy allow your dermatologist to detect suspicious lesions at their earliest and most treatable stage.

Protecting Yourself

Prevention and early detection are your strongest defenses against both BCC and SCC. Consistent daily sunscreen use (SPF 30 or higher), protective clothing, seeking shade during peak UV hours (10 AM to 4 PM), and avoiding tanning beds all reduce your risk significantly.

Equally important is knowing your own skin. Perform monthly self-examinations, paying attention to any new growth, a sore that will not heal, or a change in an existing lesion.

At Assuta and Herzliya Medical Center, Dr. Yehonatan Kaplan provides expert evaluation and Mohs surgical treatment for both basal cell carcinoma and squamous cell carcinoma. Whether your concern is a suspicious spot or a confirmed diagnosis, our clinic offers the diagnostic and surgical tools needed to ensure the best possible outcome.