Definition

• A malignant tumor of epithelial origin arising from squamous cells (flat, keratin-producing cells of the epithelium).
• Can develop in skin or any organ lined with squamous epithelium (head/neck, esophagus, lung, cervix, anus, etc.).

Common Sites & Oncology Relevance

• Skin SCC → second most common skin cancer (after basal cell carcinoma).
• Head and neck SCC (HNSCC) → associated with tobacco, alcohol, HPV infection (esp. oropharyngeal).
• Esophageal SCC → common worldwide; linked to smoking, alcohol, dietary factors.
• Lung SCC → subtype of non-small cell lung cancer (NSCLC); strongly linked to smoking.
• Cervical SCC → most common histology of cervical cancer, associated with HPV infection.
• Anal SCC → linked to HPV.

Risk Factors

• UV radiation (skin SCC).
• Carcinogens: smoking, alcohol, environmental exposures.
• HPV infection (cervix, anus, oropharynx).
• Chronic irritation/inflammation (e.g., esophagus, scars, burns).

Diagnosis

• Histopathology: malignant squamous cells, often with keratin pearls.
• Immunohistochemistry may assist in confirming origin if metastatic.

Treatment (depends on site & stage)

• Localized disease:
  • Surgery (excision, Mohs for skin SCC)
  • Radiation therapy (alternative or adjuvant)
• Locally advanced/metastatic SCC:
  • Chemotherapy: cisplatin-based regimens often standard (e.g., cisplatin + 5-FU in HNSCC, esophageal SCC).
  • Targeted therapy: EGFR inhibitors (e.g., cetuximab in HNSCC).
  • Immunotherapy: PD-1 inhibitors (nivolumab, pembrolizumab, cemiplimab, dostarlimab in selected SCCs).

Pharmacist Considerations

• Chemotherapy support: hydration, antiemetics for cisplatin; mucositis and myelosuppression monitoring.
• Immunotherapy: monitor for immune-related adverse events (colitis, hepatitis, thyroiditis, pneumonitis).
• EGFR inhibitors (cetuximab): infusion reactions, acneiform rash (requires prophylactic skin care).
• HPV vaccination is a preventive measure for cervical, anal, and oropharyngeal SCC.

Summary:

SCC (Squamous Cell Carcinoma) is a malignant tumor of squamous epithelium that can occur in many organs (skin, head/neck, esophagus, lung, cervix, anus). Treatment varies by site but often includes surgery, radiation, cisplatin-based chemotherapy, and immunotherapy. Pharmacists play a key role in toxicity prevention, monitoring, and supportive care.