Related Subjects:
|Cancer of Unknown Primary
|Palliation prescribing
|Levomepromazine
|Analgesia and Pain management
|Sedation and Analgesia on ITU
|Neuropathic Pain Management
|Codeine
|Dihydrocodeine
|Diamorphine
|Morphine
|Paracetamol (Acetaminophen)
โ Cancer of Unknown Primary (CUP) โ a diagnosis where malignant cells are identified but the primary tumour site cannot be found.
๐ In some patients, the primary lesion is never discovered despite extensive investigations.
๐ About
- Uncommon diagnosis, accounts for ~3โ5% of all cancers.
- Primary tumour may be too small, destroyed by immune response, or removed during previous surgery.
โ๏ธ Aetiology
- Primary cancer may be very small and slow-growing.
- The immune system may have eradicated the original lesion.
- The primary tumour may have been excised incidentally during earlier surgery.
๐งช Cytology
- ๐จ Squamous cell carcinoma (~5%).
- ๐ฆ Undifferentiated carcinoma / neuroendocrine tumour (~30%).
- ๐ฅ Adenocarcinoma / poorly differentiated carcinoma (~65%).
๐ Clinical Features
- Common metastatic sites: ๐ซ chest, ๐ฅผ adrenals, ๐ฆด bone, ๐ง brain.
- Ask about bowel and upper GI symptoms (colorectal, gastric origin).
- Full skin check ๐ฉบ to rule out melanoma.
๐งซ Pathology
- Excisional biopsy: Entire lump removed.
- Incisional biopsy: Portion of lump/tissue removed.
- Core biopsy (preferred): Tissue cylinder removed via wide needle.
- FNA: Cells/fluid aspirated via fine needle.
๐งญ Investigations โ โHunting the Primaryโ
- ๐งช Bloods: FBC, U&E, LFTs, TFTs, PSA, directed tumour markers.
- ๐ฅ๏ธ CT chest/abdomen/pelvis with contrast.
- ๐ฆด Bone scan if symptoms suggest skeletal spread.
- ๐งฒ MRI chest/abdomen/pelvis (second-line for clarification).
- ๐ฅ PET-CT for metabolically active disease.
- ๐ฉ Mammogram in women.
- ๐น Endoscopy (upper GI, colonoscopy) if symptoms or suspicion.
- ๐ฏ Directed tumour markers (CA-125, CgA, AFP, ฮฒ-hCG, PSA).
- Core biopsy of most accessible lesion for histology & molecular analysis.
๐งฌ Immunohistochemistry (IHC) Panels โ Common Markers
- ๐ฉท Breast: ER, GCDFP-15, mammaglobin, HER-2, GATA-3.
- ๐ซ Lung: TTF-1, surfactant protein A, napsin A.
- ๐ง Prostate: PSA, PAP, AMACR.
- ๐งฌ Lymphoma: LCA, CD3, CD20, CD45, PAX5, Bcl-2, cyclin D1.
- ๐ฉโ๐ฆฐ Ovarian/Mรผllerian: ER, WT-1, PAX8.
- ๐ช Sarcoma: Desmin, CD31, SMA, MyoD1, myogenin.
- ๐ง Neuroendocrine: Chromogranin, synaptophysin, CD56.
- ๐ผ Germ Cell: ฮฒ-hCG, AFP, OCT3/4, CD30.
- ๐ง Urothelial: CK7, CK20, GATA-3.
- ๐ฝ๏ธ Colorectal: CK7, CK20, CDX2, SATB2, CEA.
- ๐ฉบ Renal: RCC, CD10, PAX8.
- ๐งช Hepatocellular: HepPar-1, Glypican-3, Arginase-1.
- โซ Melanoma: S100, HMB-45, SOX10.
- ๐ฆ Thyroid: Thyroglobulin, TTF-1, PAX8.
๐ฉบ Management
- Multidisciplinary care via Oncology MDT is essential.
- Palliative chemotherapy may be considered in selected cases (e.g. responsive histologies).
- Supportive care โ analgesia, symptom control, palliative services โ is crucial for QoL.
๐ References
