Post-diagnosis use of risk stratification tools improves assessment of SMM patients

Despite only being validated for use at diagnosis, risk stratification scores, such as the Mayo-2018 and the International Myeloma Working Group (IMWG)-2020 criteria, appear to be viable for post-diagnosis use in patients with smouldering multiple myeloma (SMM), a recent study has found.

Researchers retrospectively enrolled 704 SMM patients (median age 65.3 years, 59.4 percent men) who were assessed using the Mayo-2018 and IMWG-2020 models. Both scores were used to restage participants at 1, 2, 3, 4, and 5 years after diagnosis, and the risk of outcomes, such as mortality and time to progression (TTP), was compared across risk ratings.

At diagnosis, 38 percent of patients were deemed low-risk by the Mayo-2018 score, while 32 percent and 29 percent were intermediate- and high-risk, respectively. When using only the diagnostic values, TTP differences among risk categories became less distinct over time.

However, re-assessment of risk at different follow-up points led to more consistent TTP estimates across groups. For example, patients deemed high-risk when Mayo-2018 was reapplied during follow-up were up to five times at greater risk of progression than low-risk counterparts.

Moreover, evolving to a higher risk category during follow-up aggravated progression risk. At the 5-year landmark, patients who were low-/intermediate-risk at baseline were nearly five times as likely to experience disease progression if they evolved to a high-risk category (hazard ratio, 4.73, 95 percent confidence interval, 2.26–9.88; p<0.001).

Similar patterns were found for IMWG 2020, such that reapplying the score at 4 years post-diagnosis allowed for consistent stratification of intermediate- and high-risk patients from low- and low-intermediate-risk counterparts.