Comparison of new patients with Bence-Jones, IgG and IgA myeloma receiving sequential therapy: the need to regard these immunologic subtypes as separate disease entities with specific prognostic criteria.

Of the 61 newly diagnosed patients with Bence-Jones (BJ) myeloma presenting to our centre between May 1986 and December 1997, 53 received sequential therapy (ST) comprising infusional chemotherapy (IC) followed by high-dose therapy and autotransplantation with interferon-alpha2b maintenance. The outcome was compared with 153 IgG and 39 IgA similarly treated myeloma patients. Response to IC and high-dose was comparable between the three subtypes but a significantly higher proportion of patients with BJ myeloma failed to receive high-dose compared to IgG (P = 0.003) and IgA (P = 0.04) myeloma. Median overall survival (OS) of patients with BJ myeloma (2.8 years) and event-free survival (EFS, 1.2 years) was significantly shorter than for patients with IgG myeloma (4.5 years, P = 0.03 and 2.1 years, P = 0.03, respectively). However, among those patients who achieved complete remission there was no difference in OS and EFS between IgG and BJ myeloma. In distinction to IgG myeloma where age and beta2M were significant, Cox analysis on presentation features identified performance status and urine total protein as having significant impact on OS. We conclude that achieving CR is an important treatment aim in patients with BJ myeloma, conferring a similar outlook on survival as in patients with the IgG subtype, and there is a need to consider different subtype-specific staging systems when evaluating the results of published or ongoing therapeutic trials.