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Cancer of Unknown Primary

Cancer of Unknown Primary (CUP) or Occult Malignancy describes a collection of rare cancers that are poorly understood. It is sometimes called carcinoma of unknown origin. Between 4%-7% of all cancers are determined to be from an unknown primary. With CUP, malignant cells have spread in the body, but the source of the cancer -- the primary tumor -- can’t be found at the time of diagnosis. Contact us at 734-647-8902

Sometimes a patient's primary cancer will never be found, even with advanced testing. The signs and symptoms are different depending on where the cancer has spread, or metastasized, in the body. Because the cancer has sometimes spread aggressively, there is a poor prognosis and generally patients are advised that they are not expected to live beyond one year after diagnosis.

Our approach to patient care and treatment

At the University of Michigan Rogel Cancer Center, we see more CUP patients than anyone else in the Midwest region. We believe that early involvement and treatment with innovative therapies improves chances for a longer, more comfortable life.

When patients are referred to our clinic, they may already be experiencing a high degree of discomfort. They and their families may have added anxiety or frustration from trying to understand a diagnosis that is so non-specific. Because of this physical and emotional burden, we offer a special focus on symptom management and patient/family communication and support, as well as innovative cancer care that is backed by the latest research.

The Clinic

Patients at the CUP Clinic receive comprehensive therapy, coordinated in a single clinic, resulting in the delivery of highly personalized clinical care. Cancer experts will review the diagnosis and biopsy to confirm CUP. Clinic doctors and other cancer specialists work closely with patients and their families to speak plainly and honestly about the diagnosis and treatment options. As leaders in the use of team-based care, we have close interaction among many cancer specialists, including medical oncologists, radiation oncologists, pathologists and molecular pathologists in the individualized management of patients with CUP. Other services include:


The CUP clinic at the Cancer Center is one of the very few in this country with a research-focused environment. Our patients benefit through better symptom control, communication and understanding of the nature of their medical condition. Patients may be eligible for clinical trials, often based on genetic mutations found in their individual cancer. Our research currently follows two paths:

  • Understanding the effect of improved patient understanding and symptom management of CUP and its care on quality of life
  • Identifying through genetic sequencing the molecular pathway that makes this cancer so aggressive

Still have questions?

The nurses at Cancer AnswerLine™ have answers. Call 800-865-1125 and you'll get a personal response from one of our registered nurses, who have years of experience in caring for people with cancer.

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