Carcinoma of Unknown Primary
Summary of Key Points
Evaluation
• No universal agreement exists on the extent of evaluation to search for a primary cancer.
• “Adequate,” early biopsy of a metastatic site is recommended to establish the diagnosis and help direct further workup.
• Basic evaluation includes the following:
• Comprehensive history and physical examination (including breast and pelvic examinations in women and testis and prostate examinations in men).
• Routine laboratory tests, chest-abdominal-pelvic computed tomographic scan, and mammography in women.
• Directed invasive tests based on symptomatology and pathological evaluation of the tumor tissue.
• Judicious pathological assessment of the metastatic tumor sample including directed immunohistochemical markers. Additional molecular markers that have a therapeutic intent are based on clinicopathological evaluation (including KRAS mutational status, Her2 (ERBB2) expression, and epidermal growth factor receptor (EGFR) mutation studies).
• The diagnostic utility of positron emission tomography (PET) is poorly defined; it is beneficial in selected patients.
• The role of tissue of origin molecular profiling assays continues to evolve; these tests are beneficial in selected patients.
