Dialysis-dependent renal failure at diagnosis continues to be associated with very poor outcome in multiple myeloma - response to Murphy et al

The study by Murphy et al supports the observation made by several groups regarding the benefit of the novel agents in both young and elderly patients affected by multiple myeloma (MM) (Kumar et al, 2008; Ludwig et al, 2008; Turesson et al, 2010; Pozzi et al, 2013). Their single institution data collected over 18 years in 262 patients shows an improvement in overall survival (OS) starting from 1995 with an OS not yet reached in the period 2007–2012, after the introduction of bortezomib in their clinical practice. However the study clearly highlights renal insufficiency as a very poor prognostic factor, with a median OS shorter than 1 year in patients requiring dialysis. In the past few years many attempts have been made to classify and stratify patients based on various refined biological characteristics, however, as clearly stated here, the clinical presentation, particularly organ damage, still represents a negative prognostic factor that not even modern medicine has been able to overcome. The introduction of the International Staging System Criteria (ISS) (Greipp et al, 2005) only indirectly takes renal function into account, while the Durie and Salmon Criteria differentiates stage ‘A’ and ‘B’ MM based on kidney damage (Durie & Salmon, 1975). However Durie-Salmon ‘B’ stage is based on a creatinine cut-off point of 177 lmol/l and it is unable to better differentiate between moderate and severe impairment of renal damage requiring dialysis. It is also unable to predict the response to the treatment and reversibility of the organ damage, between possibly transitory kidney impairment due to dehydration, hyperuricaemia and hypercalacemia, and cast nephropathy. In this subset of MM patients it would be beneficial to introduce further parameters in the staging system (i.e. glomerular filtrate; type of light chain) in order to better stratify the risks and prevent treatment-related toxicity. For this reason, ad hoc clinical trials for this group of patients are strongly needed (Haynes et al, 2012). Finally, the Murphy study highlights the selection of patients enrolled in clinical trials and the necessity to evaluate the survival in the population of every day clinical practice, together with the need to develop high resolution analysis from data collected by cancer registers. Moreover, early diagnosis, compared with late or misdiagnosis, especially for light chains MM, is mandatory to prevent severe organ damage.