Skin Cancer Types and Treatment: BCC, SCC, and Melanoma

One Person Dies From Melanoma Every Hour in the United States

Skin cancer is the most common cancer in the United States, with more than 5.4 million cases of non-melanoma skin cancer treated annually and approximately 100,640 new melanoma diagnoses expected in 2024. Despite being largely preventable through UV protection, incidence continues to rise — melanoma rates have more than doubled since the 1970s. The three primary forms — basal cell carcinoma, squamous cell carcinoma, and melanoma — differ dramatically in their behavior, treatment, and mortality risk.

Skin Cancer Type Comparison

The ABCDE Rule for Melanoma Detection

Early detection of melanoma is the most critical determinant of survival. The ABCDE criteria were developed to help clinicians and patients identify suspicious lesions:

• A — Asymmetry: one half does not match the other; benign moles are typically symmetric.
• B — Border: irregular, ragged, notched, or blurred edges; benign moles have smooth, defined borders.
• C — Color: multiple shades of brown, black, red, white, or blue within a single lesion; benign moles are uniform.
• D — Diameter: lesions greater than 6 mm (pencil eraser size) warrant evaluation, though melanomas can be smaller.
• E — Evolution: any change in size, shape, color, or a new symptom such as bleeding or crusting.

An additional feature — "ugly duckling" sign — applies to lesions that look different from a patient's other moles. The ABCDE rule has a sensitivity of approximately 65–80% and specificity of 80–90% for melanoma in clinical studies.

Breslow Thickness — The Key Prognostic Measure

Breslow thickness — the depth of melanoma invasion measured from the granular layer of the epidermis to the deepest tumor cell — is the single most important prognostic factor for melanoma. It determines surgical margins and sentinel lymph node biopsy indications.

Sentinel Lymph Node Biopsy

Sentinel lymph node biopsy (SLNB) identifies the first draining lymph node from a primary melanoma. If the sentinel node is tumor-free, the remaining regional nodes are highly unlikely to be involved. SLNB is recommended for melanomas ≥0.8 mm Breslow thickness, or thinner with high-risk features (ulceration, mitotic rate ≥1/mm²). A positive sentinel node upgrades the patient to stage III and guides systemic adjuvant therapy decisions. The MSLT-I trial (2006) established SLNB as the standard for melanoma staging; the subsequent MSLT-II trial (2017) found that completion lymph node dissection after a positive sentinel node does not improve melanoma-specific survival compared to nodal observation, changing practice significantly.

Immunotherapy for Advanced Melanoma

Advanced melanoma was once a near-uniformly fatal diagnosis. Pembrolizumab (Keytruda) and nivolumab (Opdivo), anti-PD-1 checkpoint inhibitors, transformed the landscape. PD-1 (programmed cell death protein 1) is an immune checkpoint that tumors exploit to suppress T-cell activity. Blocking PD-1 unleashes anti-tumor immune responses.

KEYNOTE-006 trial (published NEJM 2015) compared pembrolizumab to ipilimumab in advanced melanoma: pembrolizumab achieved a 5-year overall survival rate of 38.7% versus 31.0% for ipilimumab. The combination of nivolumab + ipilimumab (dual checkpoint blockade) produced even higher response rates (58%) but more significant immune-related adverse events — colitis, hepatitis, pneumonitis — requiring systemic corticosteroids in approximately 55% of patients.

BRAF-targeted therapy (vemurafenib, dabrafenib + trametinib) is available for the 40–50% of cutaneous melanomas harboring BRAF V600E/K mutations, producing rapid initial responses but with higher relapse rates than immunotherapy. Adjuvant immunotherapy after surgical resection of stage III melanoma reduces recurrence risk by approximately 40% relative to observation.

This article is for informational purposes only. Consult a qualified healthcare professional.