CUP

Meaning of CUP: CUP describes cancer confirmed on biopsy for which the original site of origin cannot be identified despite thorough evaluation.

Definition of CUP

CUP, or cancer of unknown primary, describes a situation in which cancer cells are identified in the body, typically through biopsy, but the original site where the cancer first developed cannot be determined despite thorough evaluation. The cancer found is often at a site to which it has already spread rather than where it began.

Diagnosing CUP typically involves examining the cancer cells under a microscope, along with imaging studies and laboratory testing, to look for clues about the tissue of origin, since certain patterns can point toward a likely source even when the primary site itself cannot be directly identified.

Treatment for CUP is generally guided by the features of the cancer cells themselves, including how they appear under the microscope and any identifiable molecular characteristics, since these features can suggest which treatment approaches, normally chosen based on where a cancer began, are most likely to be effective.