Cancer of Unknown Primary Site or CUP, Cancer of Unknown Primary is a tumor that is diagnosed at a metastatic site and the primary site is not known. Following additional testing many of these cancers are diagnosed with a primary site. Per the National Cancer Institute, 2% to 4% of these primary tumor site remain unknown.
The American Cancer institute ranks this as a “dangerous” cancer with an often poor prognosis due to these factors:
- Most are fast-spreading cancers.
- Because the exact type of cancer is not known, it is more difficult for doctors to know what treatment is most likely to help the patient.
- Because the cancer is usually widespread, it is rarely curable.
The next step in diagnosis is to classify the tumor in an effort to best treat the cancer.
As with any cancer, early diagnosis is the key. Have routine cancer related check-ups. See your doctor if you have symptoms that include:
- Shortness of breath
- Swollen lymph glands
- Abdominal tenderness and/or bloating
- Pain in the chest or abdomen
- Bone pain
- Skin tumors
- Weakness, fatigue, general malaise, weight loss
Diagnosis begins with:
- Physical exam, including a gynecological exam
- Blood tests, including tumor markers, tests for blood in stool and to evaluate kidney function
- Radiographic imaging, including, chest X-ray, mammogram, abdominal CT
- Biopsy and possible endoscopic exam
Special Lab Tests Used to Evaluate Biopsy Specimens:
- Immunohistochemistry, slices of tissue samples are treated with an antibody to rule out what type of cancer is not present
- Electron Microscopy, a microscope using beams of electrons to determine specific cell characteristics
- Polymerase Chain Reaction, this method may be able to detect abnormal DNA or RNA in a specimen
- Tissue Stains , specific stains such as Prostate-specific antigen, or Alpha-fetoprotien (for primary liver cancer).
Treatment is specific to the type of cancer that is suspected, or the subgroups of cancer that that is a probably diagnosis. Treatment is also determined according to staging and may include:
- Hormone therapy
For more information on treatment options and staging please visit the American Cancer Institute site.
Resources and Support for CUP:
Cancer of Unknown Primary Foundation, “Making the Unknown Known.” A UK organization that provides support, information and advocacy.
Battling Books: The Following are Clinical Books on the Topic.