Patterns of Disease Relapse and Progression in Patients with Multiple Myeloma After First Line Therapy with Autologous Stem Cell Transplantation: Implications for Patient Monitoring After Transplantation

Autologous stem cell transplantation (ASCT) is a widely used therapeutic option in first line treatment of multiple myeloma (MM). However, many patients eventually relapse. While precise knowledge of relapse and progression (R/PD) patterns would be important to generate evidence based surveillance recommendations after ASCT, such data is limited in the literature, especially in the era following the introduction of the free light chain assay. The purpose of this study is to examine the patterns of post-ASCT relapse and to derive evidence based recommendations for optimal surveillance of patients.

We performed a retrospective analysis on 258 patients with MM who underwent ASCT within one year of diagnosis at MSKCC between 2000 and 2010, as part of first line therapy. We used the IMWG standard criteria for serologic and clinical R/PD. We first determined for all patients the date of serologic R/PD. Patients identified as having serologic R/PD were further examined to determine whether clinical (anemia, renal failure, hypercalcemia, development of soft tissue lesions), radiologic (skeletal survey) or urinary R/PD had anteceded serologic R/PD. Several groups of patients were derived and further analyzed in terms of relapse patterns and adequacy of follow up.

Among 258 patients, 173 were determined to have serologic R/PD at a median of 19.2 months post-transplant. Among these patients, on the dates of their serologic R/PD, 17 (9.8%) had concurrent overt symptomatic evidence of clinical/radiologic R/PD (Group A symptomatic R/PD), while 156 (90.2%) were found to have isolated asymptomatic serologic R/PD without apparent evidence of concomitant clinical/radiologic R/PD (Group B asymptomatic R/PD). Group A included patients with distinct and sometimes coinciding clinical characteristics (poor risk cytogenetics with aggressive disease (n=3), leptomeningeal relapse (n=1), soft tissue relapse (n=4) and acute severe anemia at relapse (n=3)); patients with IgA gammopathy (n=5); and patients considered to have inadequate serologic follow up intervals (range of follow up interval between date of serologic R/PD and prior serologic testing 149 to 245 days) (n=6). Upon further examination of group B, 44 patients had radiologic imaging at the time of serologic R/PD (within 4 weeks following the date of serologic R/PD). Fourteen among them (32%) had evidence of new bone lesions. Among all 173 patients with serologic R/PD, 83 patients had a skeletal survey within one year prior to the date of serologic R/PD. Only 3 (3.6%) had evidence of radiologic R/PD anteceding serologic R/PD. All 3 patients were considered to have had inadequate serologic follow up interval (Range 208 to 252 days). Abnormal urine immunofixation (UIF) anteceded serologic R/PD in 5 out of 41 (12%) patients tested who had achieved CR post transplant. In these patients the abnormal UIF anteceded the serologic R/PD by a mean of 2.4 months. Abnormal UPEP anteceded serologic R/PD by 1.9 months in only 1 out of 40 (2.5%) patients tested who had achieved less than CR post transplant.

Based on the results of this analysis, several conclusions can be drawn: 1) The vast majority of R/PD in patients with MM are asymptomatic R/PD detected first by serologic studies. A small percentage of patients (those with aggressive cytogenetics, specific relapse types including soft tissue, severe cytopenia, and IgA gammopathy) will have symptomatic R/PD with overt concomitant evidence of clinical and/or radiologic R/PD at the time of serologic R/PD; 2) Among patients who have apparent asymptomatic R/PD, a significant percentage will have evidence of skeletal lesions and therefore imaging should be recommended in these patients; 3) In the absence of serological R/PD, routine surveillance screening with yearly skeletal surveys cannot be recommended based on this analysis since this test was not useful in any of the analyzable patients in whom it was obtained; 4) Aside from few patients in CR whose relapse may be detected earlier by UIF (with probably no clinical benefit), all patients with multiple myeloma whose disease progresses will have serologic R/PD at the time of progression and follow up limited to serologic testing may well be sufficient for monitoring patients with MM post transplant.

No relevant conflicts of interest to declare.