Definition
Carcinoma is a malignant tumor arising from epithelial cells (cells that line the skin, glands, and internal organs).
- Origin: Epithelial tissue (e.g., skin, mucous membranes, glandular epithelium).
- Common sites: Skin, lung, breast, colon, prostate, pancreas, etc.
- Histologic types:
- Squamous cell carcinoma – from squamous epithelium.
- Adenocarcinoma – from gland-forming epithelium.
- Others: basal cell carcinoma, transitional cell carcinoma, etc.
- Spread pattern: Often via lymphatics first, then hematogenous spread.
- Clinical relevance: Most common form of cancer in adults; treatment may involve surgery, chemotherapy, radiotherapy, targeted therapy, or immunotherapy depending on stage and molecular profile.
Carcinoma Classification
| Type | Tissue of Origin | Common Sites | Key Molecular Markers / Mutations | Example Targeted Therapies | Notes for Pharmacist |
|---|---|---|---|---|---|
| Squamous Cell Carcinoma (SCC) | Squamous epithelium | Skin, head & neck, lung, esophagus, cervix | EGFR overexpression, PIK3CA mutations | EGFR inhibitors (cetuximab), immune checkpoint inhibitors (pembrolizumab, nivolumab) | Monitor for mucositis, rash (EGFRi), immune-related toxicities (ICI) |
| Adenocarcinoma | Gland-forming epithelium | Breast, lung, colon, pancreas, prostate | HER2, KRAS, EGFR, ALK, ROS1, BRAF | HER2: trastuzumab, pertuzumab; EGFR TKIs; ALK inhibitors; BRAF inhibitors | Verify molecular testing before dispensing targeted agents; watch for cardiotoxicity (HER2), diarrhea (EGFR TKIs) |
| Basal Cell Carcinoma (BCC) | Basal layer of epidermis | Skin (sun-exposed) | PTCH1 mutations (Hedgehog pathway) | Vismodegib, sonidegib (Hedgehog inhibitors) | Counsel on teratogenicity and dysgeusia; rare metastatic potential |
| Transitional Cell Carcinoma (TCC) / Urothelial Carcinoma | Transitional epithelium | Bladder, ureter, renal pelvis | FGFR3 mutations, PD-L1 overexpression | Immune checkpoint inhibitors, FGFR inhibitors (erdafitinib) | Monitor immune toxicities; hydration with cisplatin-based chemo |
| Renal Cell Carcinoma (RCC) – clear cell subtype | Renal tubular epithelium | Kidney | VHL mutations → VEGF overexpression | VEGF inhibitors (sunitinib, pazopanib), mTOR inhibitors, ICI combos | Hypertension, proteinuria (VEGF TKIs), stomatitis (mTORi) |
| Hepatocellular Carcinoma (HCC) | Hepatocytes (epithelial origin) | Liver | VEGF pathway activation | Sorafenib, lenvatinib, atezolizumab + bevacizumab | Monitor for bleeding risk with bevacizumab; hepatic function monitoring essential |
| Cholangiocarcinoma | Biliary epithelium | Intrahepatic/extrahepatic bile ducts | IDH1 mutations, FGFR2 fusions | Ivosidenib (IDH1), FGFR inhibitors | Watch for hyperphosphatemia (FGFRi) |
Pharmacist Tips
- Always verify histologic subtype and molecular profile before dispensing targeted therapy.
- Many carcinomas share common pathways (EGFR, VEGF, PD-1/PD-L1), but drug choice is biomarker-driven.
- Monitor for organ-specific toxicities:
- EGFR inhibitors → skin rash, diarrhea
- VEGF TKIs → hypertension, bleeding
- Immunotherapy → autoimmune endocrinopathies, colitis, pneumonitis