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Malignancy of Unknown Primary Origin (MUO) / Carcinoma of Unknown Primary (CUP)

Clinical Lead: Sonali Dasgupta

Deputy Clinical Lead: Dr Laura Jones, Specialist Oncologist, South West Wales Cancer Centre

This page provides information and guidance on Malignancy of Unknown Primary Origin (MUO) / Carcinoma of Unknown Primary (CUP) for healthcare professionals. 

Information for patients can be found on our patient hub.

If would like further information on the Malignancy of Unknown Primary Origin (MUO) / Carcinoma of Unknown Primary (CUP) please click here to contact us.


A summary of the first all Wales Cancer of Unknown Primary (CUP) education and networking event (January 2024).


The event was attended by around 90 delegates from all parts of Wales, with 11 faculty members and two additional guest speakers of international repute. Ongoing high quality work within individual health boards were showcased. Topical themes of presentations included standardising CUP/MUO patient pathways in Wales, bridging the gap between primary care referrals and early oncology/ specialist palliative team access via Rapid Diagnostics Clinics (RDC). MUO clinics in health boards, equity in Clinical Nurse Specialist (CNS) support, as well as clinical trials/studies and the pivotal role of CUP/MUO MDT in making holistic patient-centred care plans in this very complex clinical cohort.

The expert speakers included Dr Kai-Keen Shiu, Consultant Medical Oncologist and Honorary Associate Professor (UCL Cancer Institute) and John Symons, Director of the Cancer of Unknown Primary (CUP) Foundation - Jo's friends. Topics of discussion included the evolution in our scientific understanding of this challenging diagnosis and recent advances made in medical research in this patient group. This inaugural event has received very positive formal feedback from all attendees. A clear ambition and keen interest was evident, in improving clinical outcomes and patient experience in this vulnerable group of patients in Wales, in collaboration with national and international partners.

To find out more contact us.


ESMO 2023 - Cancer of unknown primary: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up

NICE 2010 (updated April 2023) - Metastatic malignant disease of unknown primary origin in adults: diagnosis and management

Cancer Research UK (CRUK) - Cancer of unknown primary (CUP)

Jo’s friends

South East Wales

Clinical Lead: Dr Sonali Dasgupta – MDT frequency: Weekly Thursdays 1.30pm – Email:

Click here to download the South East Wales referral form.

South West Wales

Swansea Bay MUO

Click here to refer to SBUHB Malignancy of Unknown Origin MDT.

To email SBUHB MUO click here.

North Wales (details TBC)