Cutaneous squamous cell carcinoma (SCC), a prevalent type of non-melanoma skin cancer, originates from keratin-producing cells in the epidermis. This invasive cancer, which can metastasize and be lethal, extends beyond the epidermis. Other forms like intraepidermal carcinoma (SCC in situ) and mucosal SCC are discussed separately.

SCC is more common in older males, but it also affects females and younger adults. Previous history of SCC or other skin cancers, such as basal cell carcinoma and melanoma, increases the risk. Other risk factors include actinic keratoses, outdoor activities, smoking, fair skin with blue eyes and light hair, previous skin injuries or certain diseases, genetic conditions like xeroderma pigmentosum, and exposure to specific risk factors like ionizing radiation, arsenic, immune suppression, and certain medications. Organ transplant recipients are particularly vulnerable.

Over 90% of cases are linked to DNA mutations caused by various factors, including UV radiation, cigarette smoking, aging, and immune suppression. Infections with certain types of human papillomaviruses also contribute, especially in immunocompromised individuals.

Symptoms include enlarging lumps that scale or crust, often developing from pre-existing skin lesions. These lumps, which can be painful, are typically found on sun-exposed areas. They vary in size and may ulcerate. Different clinical types of invasive SCC include cutaneous horns, keratoacanthoma, verrucous carcinoma, Marjolin ulcers, and multiple eruptive SCC/KA-like lesions associated with specific syndromes.

SCC is categorized based on the likelihood of recurrence and metastasis. High-risk features include large size, location on sensitive areas like the face or hands, arising in elderly or immune-compromised patients, certain histological features, and deep tissue invasion.

In 2011, the American Joint Committee on Cancer (AJCC) introduced a new staging system for cutaneous squamous cell carcinoma (SCC) in the 7th Edition of their manual. This system measures the size of the primary tumor (T) and its spread to lymph nodes (N).

Staging of cutaneous SCC includes:

– TX: Primary tumor cannot be assessed

– T0: No primary tumor detected

– Tis: Carcinoma in situ

– T1: Tumor ≤ 2cm, lacking high-risk features

– T2: Tumor ≥ 2cm or ≤ 2 cm with high-risk features

– T3: Tumor invading the maxilla, mandible, orbit, or temporal bone

– T4: Tumor invading the axial or appendicular skeleton, or perineural invasion at the skull base

Nodal staging:

– NX: Inability to assess regional lymph nodes

– N0: No metastasis in regional lymph nodes

– N1: Metastasis in a single local lymph node ≤ 3cm

– N2: Metastasis in a single local lymph node ≥ 3cm, or in multiple nodes ≤ 6cm

– N3: Metastasis in lymph nodes ≥ 6cm

Diagnosis of cutaneous SCC relies on clinical features and is confirmed through biopsy or excision. Patients with a high-risk diagnosis may need further tests to check for spread to lymph nodes or other areas, including ultrasound, X-rays, CT, and MRI scans, as well as lymph node or tissue biopsies.

Treatment typically involves surgical removal, usually with a 3–10 mm margin of healthy tissue around the tumor. Additional methods include shave, curettage, and electrocautery for low-risk tumors; cryotherapy for small, thin tumors; Mohs surgery for large facial tumors or recurrences; and radiotherapy for inoperable tumors or as an adjunct treatment.

In cases of advanced primary, recurrent, or metastatic SCC, a combination of treatments, often involving surgery, radiotherapy, cemiplimab, and experimental therapies targeting the epidermal growth factor receptor, is common. This requires a multidisciplinary approach.

Preventive measures, especially sun protection, are crucial to reduce SCC incidence, particularly for the elderly, those with fair skin, and immunocompromised individuals. Protective strategies include staying indoors or seeking shade during midday, wearing protective clothing, applying SPF50+ sunscreen, and avoiding indoor tanning. Oral nicotinamide and retinoids like acitretin or isotretinoin can also help those at high risk.

Early treatment, particularly for small lesions, enhances the likelihood of curing SCC. The risk of recurrence or related death increases with larger or thicker tumors. Approximately half of the high-risk individuals develop another SCC within five years of the first and have an increased risk of other skin cancers. Regular self-examinations and annual checks by professionals are recommended for these individuals.

Centre for Medical and Surgical Dermatology offers different treatment methods for SCC that are unique to each patient. For more information on Dermato-oncology visit the following link:

Dermato-oncology