Both hypodiploidy and deletion of chromosome 13 independently confer poor prognosis in multiple myeloma

Complete or partial deletion of chromosome 13 or translocations involving 13q (Δ13) by conventional cytogenetic analysis confers a poor prognosis in multiple myeloma (MM) patients, even with timely application of tandem autologous transplants. It was recently suggested that the prognostic significance of Δ13 is related to its frequent association with hypodiploidy but by itself does not have a poor prognostic significance. We therefore analysed our experience in 1475 consecutive MM patients in whom we intended treatment with tandem transplants after a melphalan‐based conditioning regimen. Patients with abnormal cytogenetic analysis were grouped into hypodiploid/hypotetraploid, pseudodiploid and hyperdiploid groups, according to their modal chromosome number. Their event‐free and overall survival were compared with those of patients with a normalkaryotype. Both hypodiploidy and Δ13 were found to independently confer poor prognosis in MM patients. Furthermore, these parameters in combination with easily obtained pretransplant levels of β‐2 microglobulin and albumin define three groups of MM patients with clearly distinct outcomes.