International Staging System - ISS (Multiple myeloma)

Additional Information

Score Description

The International staging system (ISS) is a staging system to classify patients with multiple myeloma, which was introduced 2005. The Staging system was developed based on 10750 previously untreated patients with myeloma from over 17 institutions worldwide .  The ISS should only be used in symptomatic myeloma, since its value in smoldering myeloma and monoclonal gammopathy of undetermined significance (MGUS) is not known. The ISS stage retains prognostic relevance in the era of novel agents (thalidomide, bortezomib, lenalidomide) (Kastritis et al. 2009).

Definition

Stages Criteria
I Serum β2-microglobulin < 3.5 mg/l
Serum albumin > 35 g/l
II Neither stages I nor III
(There are two categories for stage II: serumβ2-microglobulin <3.5 mg/l but serum albumin <35 g/l; or serumβ2-microglobulin 3.5 to 5.5 mg/l irrespective of the serum albumin level)
III Serum β2-microglobulin > 5.5 mg/l

Further Reading

Greipp PR et al. International staging system for multiple myeloma. J Clin Oncol. 2005 May 20;23(15):3412-20.