FROM JAMA ONCOLOGY

A large, population-based Swedish study found that patients with multiple myeloma who had prior knowledge of monoclonal gammopathy of undetermined significance had better overall survival than patients without prior knowledge, according to a report published online March 5 in JAMA Oncology.

Despite having a higher prevalence of comorbidities, those with prior knowledge of monoclonal gammopathy of undetermined significance (MGUS) had significantly higher median survival than patients without prior knowledge (hazard ratio, 0.86; 95% confidence interval 0.77-0.96; P < .01), Ms. Elin Edda Sigurdardottir of the University of Iceland, Reykjavik, and her associates report.

“We speculate that the reason for the prolonged survival observed in our study most likely reflects the fact that MGUS patients are evaluated more often for signs of MM [multiple myeloma] progression and may be diagnosed and started on antimyeloma therapy at an earlier stage. This argues for early treatment approaches in MM and raises the question of whether systematic screening for MGUS should be initiated,” they said (JAMA Oncol. 2015 March 5 [ doi:10.1001/jamaoncol.2015.23 ]).

Virtually all cases of MM are preceded by MGUS, characterized by detectable serum M protein and the absence of end-organ damage. Most MGUS cases go undiagnosed, and only a fraction progress to malignant disease, with absolute risk of progression 0.5%-1% per year. Studies show MGUS is present in 2%-3% of adults aged 50 years and older and about 5% of adults aged 70 years and older.

The population-based study analyzed Swedish national health registry data from 1976 to 2005 and included 14,798 MM patients, 394 (2.7%) of whom had previously been diagnosed with MGUS. MGUS was typically detected as part of a medical work-up for another cause, and patients with prior MGUS knowledge had significantly more comorbidities, including autoimmune diseases, infections, ischemic heart disease, heart failure, cerebrovascular diseases, and renal diseases (P < .001 for all comparisons).

Among the subset of patients with prior knowledge of MGUS, the median M-protein concentration at diagnosis was 1.2 g/dL. Surprisingly, those with M-protein concentrations less than 0.5 g/dL had poorer survival than did those with greater M-protein concentrations (HR, 1.86; 95% CI, 1.13-3.04; P = .01). The authors speculate this may be due to current guidelines that suggest less frequent monitoring of individuals with lower M-protein concentrations.

“Our findings raise the question whether screening for MGUS in the general population could translate into earlier detection and treatment of MM and lead to better MM survival,” Ms. Sigurdardottir and her associates wrote.

tor@frontlinemedcom.com

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