[2018 Consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary]

Abstract

Cancer of unknown primary is defined as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They differ from other primary tumours in their biological features and how they spread, which means they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, cancer of unknown primary can account for 2-9% of all cancer patients, mostly 60-75 years old. This article reviews the main clinical, pathological and molecular studies conducted to analyse and determine the origin of cancer of unknown primary. The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed.

Keywords: Anatomía patológica; Biopsia; Biopsy; Cancer of unknown primary; Chemotherapy; Cáncer de origen desconocido; Diagnosis; Diagnóstico; Histopathology; Immunohistochemistry; Inmunohistoquímica; Molecular pathology; Patología molecular; Prognosis; Pronóstico; Quimioterapia.