Cancer of Unknown Primary (CUP) may also be called Carcinoma of Unknown Primary Site or Occult Primary Cancer. This means that the cancer has already spread (metastasized) when it is found, but doctors do not know where it started (primary site). The metastatic tumour is found before the primary cancer is identified. The primary site may be identified after further testing, but the primary site is never found in many cases. CUP is also not a single type of cancer, but a group of different cancer types.
About this Cancer
Symptoms of Cancer of Unknown Primary can include:
- Fatigue
- A persistent cough
- Unexplained weight loss
- Nausea/vomiting
- Inflamed lymph nodes and belly
- Pain on one side of the body
- Fever with no specific cause
From Mayo Clinic
Risk factors for Cancer of Unknown Primary can include:
- Smoking
- Poor diet
- Lack of physical activity
- Carrying excess weight
- Sun and use of tanning beds/sun lamps
The following can be used to diagnose Cancer of Unknown Primary
- Physical examination
- MRI, CT scan, PET scan,
- Biopsy
If a biopsy shows that the cancer cells originated elsewhere, your healthcare team will order other tests to try and find where they started.
From Mayo Clinic
The following can be used to treat Cancer of Unknown Primary
- Chemotherapy
- Immunotherapy
- Targeted therapy
- Radiation therapy
- Surgery
- Palliative care
From Mayo Clinic
Stories from Survivors
We currently do not have any stories on cancer of unknown primary. If you know of any, please share them with us at info@survivornet.ca.
Resources
- November 9 2024 – Evolution in the diagnosis and treatment of carcinoma of unknown primary: a multicenter Canadian analysis | The Oncologist – Oxford Academic
- September 16 2025 – Large language models enable tumor-type classification and localization of cancers of unknown primary from genomic data – ScienceDirect
- January 23 2023 – A qualitative study of patients with Cancer of Unknown Primary: Perceptions of communication, understanding of diagnosis and genomic testing, and information needs – Wolyniec – 2023 – Psycho-Oncology – Wiley Online Library
- January 25 2021 – Cancer of Unknown Primary: Challenges and Progress in Clinical Management – MDPI
- January 2026 – Management and survival of patients with cancer of unknown primary discussed by a French national multidisciplinary tumour board: a retrospective analysis – The Lancet Regional Health
Cancer of Unknown Primary Cancer Groups
There are currently no Cancer of Unknown Primary organizations in Canada at this time. We will continue to add resources as they become available. If you know of any organizations, please email us at info@survivornet.ca