Carcinoma of Unknown Primary


A carcinoma is a cancer that begins in the cells that line the inside or outside of a body organ. There are different types of carcinomas, the two most common being squamous cell carcinoma and adenocarcinoma.

Carcinoma of Unknown Primary (CUP) is a condition where cancer cells are found in the body, but the place where the cells first started growing (the primary site) cannot be determined. CUP is sometimes called unknown primary cancer or unknown primary tumor.

If testing eventually identifies the primary site of the cancer, then it is no longer considered a Cancer of Unknown Primary. It is renamed and treated according to where it started.

General information

When cancer is found, it is only natural to want to know where it started. But the main reason to look for the primary site of a CUP is to guide treatment. Since cancer that starts in one place needs the same treatments when it spreads, knowing where a cancer started tells the doctor what types of treatments to use. This is especially important for certain cancers that respond well to specific chemotherapy or hormone drugs. When the types of cancer with the best hope for responding to treatment have been ruled out by certain tests, it usually becomes less important to find the exact origin or cancer type.

Most people with CUP present with multiple areas of involvement in organs in the cavities of the body — the most common being the lungs, bones, lymph nodes, and liver. Patients with CUP are presumed to have stage IV disease at the time of initial presentation.

The diagnosis of Carcinoma of Unknown Primary often creates anxiety among patients and caregivers, who may feel that the evaluation has been incomplete. About three to five percent of all cancer patients have a cancer whose primary site is never identified. It is the seventh or eighth most common cancer diagnosis.

Social Security POMS DI 23022.685 and 13.00 Malignant Neoplastic Diseases – Adult

CUP is listed under the Social Security Administration’s (SSA) Compassionate Allowance Program, which was launched in 2008 to expedite certain disability claims. Applying for disability benefits under the Compassionate Allowance Program requires the same procedure every applicant must follow when applying for SSA disability benefits; however, you will be notified if your condition is being considered as a compassionate allowance.

CUP meets SSA Medical Listing 13.27 upon confirmed diagnosis, regardless of the effectiveness of treatment. The exception is squamous cell carcinoma of unknown primary site confined to the neck nodes, which is evaluated under SSA Medical Listing 13.02. Diagnostic testing for CUP includes biopsy, imaging studies, and laboratory analysis.

The incidence of CUP increases with age; the median age on presentation for both men and women ranges from 59-66 years. The prognosis for patients with CUP origin with multiple organ involvement and poor response to treatment is grave.

Your representative may be able to help expedite your disability claim if you have a diagnosis of CUP.