Cancer of Unknown Primary

Introduction

1. Patients with ‘cancer of unknown primary origin’ have metastatic malignant disease without an identifiable primary site representing 3-5% of all malignancies (Pavlidis and Fizazi 2009).  
2. The type of tumour, the extent of its spread, and the outcome of treatment can all vary widely.  Most patients have malignancy that appears to derive from epithelial cells, that is, ‘carcinoma of unknown primary origin’ (CUP).
3. Patients with tumours of non-epithelial lineage (melanoma, sarcoma, lymphoma, germ cell) may present without an identifiable primary site but can often be managed satisfactorily despite this so, if confirmed, should be referred to the relevant site specialist team and are not considered further here.

Definitions

1. The term CUP is used broadly, often for patients who have had only limited investigations. The NICE guideline for CUP (2010) recommends the definition of ‘malignancy of undefined primary origin’ (MUO) for patients who present with metastatic malignancy identified on clinical examination or by imaging, without an obvious primary site.
2. ‘Provisional carcinoma of unknown primary origin’ (provisional CUP) can be used once the radiological abnormality has been biopsied and pathology confirms epithelial, neuro-endocrine or undifferentiated lineage, after initial, but not exhaustive investigations.
3. If a primary site is not found after review by a cancer specialist, the results of any further targeted investigations are complete, and review at the CUP MDT then a diagnosis of ‘confirmed CUP’ is made.

Referrals

1. Patients with, or suspected to have, cancer of an unknown primary should be referred to The Edinburgh Cancer Centre. The Edinburgh team can also be contacted for advice. Contact details are within the referral form via link below.  In general, it is better to refer sooner rather than later, even if all recommended investigations have not been completed.
2. For MUO, the NICE guideline recommends CUP MDM discussion, named nurse support, patient review and oncology input at the stage of initial suspicion of cancer

Online Oncology Quality System (OOQS)

1. The Edinburgh Cancer Centre provides information on CUP and MUO on their NHS Lothian intranet – see links below to Diagnostic Pathways and Referral Form
2.  Lucy Heycock is the CNS responsible for CUP patients in NHS Dumfries & Galloway and can be contacted on 01387 241680, Ext 33680 or [email protected]
3. Consider early referral to the Specialist Palliative Care team where appropriate.

Links

1. mCUP Diagnostic Pathway (OOQS)
2. mCUP Referral Form (OOQS)
3. MUO Pathway (OOQS)
4. NICE Guideline CG104 . Metastatic malignant disease of unknown primary origin.
5. Pavlidis N, Fizazi K (2009) Carcinoma of unknown primary (CUPS). Critical reviews in Oncology Hematology 69: 271-278. [Full text requires Knowledge Network Login]

Content by Lucy Heycock