Revised myeloma staging system serves as valuable predictor for survival

NEW YORK — A new prognostic staging system created for risk stratification of patients with multiple myeloma appeared to be a valuable predictor of OS and PFS, according to retrospective study results presented at Lymphoma & Myeloma 2015.

Because multiple myeloma is a heterogeneous disease, accurate and simple tools are needed to improve management of newly diagnosed patients, according to Juliana Bastos, MD, of Hospital Sao-Joao in Portugal, and colleagues.

Members of the International Myeloma Working Group described the Revised International Staging System (R-ISS) in a report published earlier this year in Journal of Clinical Oncology.

The revised system accounts for ISS stage, lactate dehydrogenase (LDH) levels and cytogenetic abnormalities, including three — deletion 17 p, t(4;14) translocation and t(14;16) translocation — that are predictive of high-risk disease.

Based on R-ISS scores, patients are divided into three categories. Patients with no high-risk cytogenetic abnormalities and normal LDH are classified as R-ISS I. Patients with high-risk cytogenetic abnormalities and high LDH are classified as R-ISS III. All other patients are classified as R-ISS II.

Bastos and colleagues applied the revised staging criteria to a cohort of patients from their center diagnosed with myeloma between 2009 and 2014.

Researchers assessed correlations between staging criteria and survival outcomes. A subanalysis examined survival outcomes based on whether patients underwent autologous stem cell transplantation (ASCT).

The cohort included 90 patients, of whom 6.7% were classified as R-ISS I, 56.6% were classified as R-ISS II and 36.7% were classified as R-ISS III.

Overall, the risk stratification system significantly discriminated survival (OS, P = .029; PFS, P = .048).

Median OS was not reached in the R-ISS I group, 23 months in the R-ISS II group and 17 months in the R-ISS III group.

Researchers reported 2-year OS rates of 100% in the low-risk group, 48.9% in the moderate-risk group and 27.5% in the high-risk group. Three-year OS rates were 66.7% in the low-risk group, 40% in the moderate-risk group and 22% in the high-risk group.

The staging system also predicted median PFS (24 months for low risk, 22 months for moderate risk and 15 months for high risk), 2-year PFS (30% for low risk, 42.4% for moderate risk and 21.8% for high risk) and 3-year PFS (30% for low risk, 31.8% for moderate risk and 21.8% for high risk).

“According to ASCT, the prognostic value of the score lost statistical significance; however, there was an obvious tendency in the association between high-risk score and adverse outcome,” Bastos and colleagues wrote. “The reduced number of patients may have limited the comparison between groups.”

The distribution of R-ISS scores was similar between the group that underwent ASCT (n = 36) and the group that did not (n = 53).

Among those who underwent ASCT, median PFS was 24 months for those with R-ISS I disease, 35 months for those with R-ISS II disease and 17 months for those with R-ISS III disease. Median OS was not reached in the R-ISS I group, 47 months for the R-ISS II group and 21 months for the R-ISS III group.

Among those who did not undergo transplant, median PFS was 19 months for those with R-ISS I disease, 15 months for those with R-ISS II disease and 7 months for those with R-ISS III disease. Median OS was not reached in the R-ISS I group, 17 months in the R-ISS II group and 10 months in the R-ISS III group.

“Conclusions may be limited in this series attending to the small number of patients,” Bastos and colleagues wrote. “Nonetheless, R-ISS emerges as a valuable predictor of outcome for both OS and PFS, with a clear tendency to discriminate higher-risk groups and, thus, identifying patients with poorer outcome [who] can benefit from intensive treatment.” – by Mark Leiser

Reference:

Bastos J, et al. Abstract P7. Presented at: Lymphoma & Myeloma 2015: An International Congress on Hematologic Malignancies; Oct. 22-24, 2015; New York.

Disclosure: Healio.com was unable to confirm the researchers’ relevant financial disclosures.