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).
|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|