The utility of serum amylase as a prognostic marker in multiple myeloma.

BACKGROUND

Ectopic production of amylase by tumor cells is known since 1951. Elevated amylase in multiple myeloma (MM) was first described in 1988. It has been postulated that translocation of chromosome 1, where amylase gene is situated, is responsible for ectopic production from the malignant plasma cells. Anecdotal reports have shown hyperamylasemia in MM to be associated with extensive bone disease, rapid progression, and shorter survival. Serum amylase estimation is a ubiquitous test. This prospective study was conducted to ascertain the degree of elevated amylase, its clinical utility, and implications in MM patients.

MATERIALS AND METHODS

In an 18-month period, all consenting patients with newly diagnosed or relapsed MM were tested for serum amylase levels. The study excluded patients with elevated lipase, abnormal creatinine clearance, and evidence of intestinal obstruction or perforation. Patients with amylase value >100 U/L were designated to have "elevated amylase level" for the purpose of this study.

RESULTS

We enrolled 58 patients with MM, of which 29.3% (n = 17) were found to have elevated serum amylase levels. The median age of patients with elevated amylase was 65 years. The male-to-female ratio was 1.9:1. There was no statistical association between age, gender, type of heavy chain class, light chain, or high-risk cytogenetics. Among patients with the International Staging System (ISS), Stages I, II, and III, 20.8% (n = 5), 31.3% (n = 5), and 41.2% (n = 7) were noted to have elevated amylase levels. A statistically significant association was noted between the presence of extramedullary disease (EMD) and elevated amylase level (P = 0.028). Higher mortality (29.4% versus 17%) and shorter mean survival of (30.2 ± 3.3 months versus 51.7 + 4.9 months) were recorded in patients with elevated amylase levels in comparison to those with normal levels.

CONCLUSIONS

Elevated serum amylase level in MM is indicative of advanced ISS stage, the presence of EMD, higher risk of mortality, and shorter survival. Serum amylase can be used as a cost-effective tool in myeloma management.