site-agnostic

Cancer found already spread, where doctors cannot find where it started. Genomic profiling finds a drug target in about a third of cases and tumour-agnostic approvals apply directly; the rest still rely on general-purpose chemotherapy, which is what those tests are changing.

Favourable subsets of cancer of unknown primary are the roughly one in five cases where the pattern of spread, the microscope appearance or blood markers point strongly to a particular cancer even though no primary can be found. They are treated as that cancer would be, for example breast cancer for a woman with cancer only in armpit nodes, and many are curable or controllable for years.

Unfavourable cancer of unknown primary is the large majority of cases, where a metastatic adenocarcinoma or poorly differentiated carcinoma fits no recognised pattern and its origin cannot be found. Treatment has long been general-purpose platinum chemotherapy, but CUPISCO showed that matching drugs to the tumour's genetic faults after short chemotherapy holds the disease longer.