Connect MM®—the Multiple Myeloma (MM) Disease Registry: Incidence of Second Primary Malignancies (SPM)

Background: Increased rates of SPM have been observed as newer cancer treatments have improved survival over the past 2 decades (Fraumeni et al. NCI, 2006). Higher incidence of specific types of hematologic SPM following MM, especially acute myeloid leukemia and myelodysplastic syndromes, have been reported relative to the general population (Dores et al. NCI, 2006; Mailankody et al. Blood, 2011; Ravazi et al. Blood, 2011; Landgren and Mailankody. Leukemia, 2014). A complex interplay between myeloma-, host-, environmental-, and treatment-related factors likely contributes to the increased incidence of SPM in MM. Connect MM is the first and largest prospective, observational, US-based, multicenter registry designed to characterize patients (pts), treatment patterns, and outcomes in newly diagnosed MM (NDMM) pts.

Methods: Between September 2009 and November 2012,a total of 1493 NDMM pts were enrolled from 234 US sites within 2 mos of the first diagnosis of MM. Patient data were collected at baseline and each subsequent quarter using a standardized form. Invasive SPM included hematologic and solid tumor second cancers and non-invasive SPM were defined as non-melanoma skin cancers (NMSC). SPM incidence and incidence rate (IR; number of pts with SPM per 100 patient-yrs [PY]) were calculated for all pts and by exposure to specific treatments, including lenalidomide (LEN). PYs were calculated as the observation period from the start of treatment until the detection of the first reported SPM (per category), death, or end of follow-up (pt lost or data cutoff).

Results: As of Dec 10, 2013, SPM data were available for 1493 NDMM pts. The median age was 67 yrs (range, 24-94 yrs), 82% of patients were white and 57% were male. Median follow-up was 29.0 mos (0-49 mos). The median OS of treated pts was 44.4 mos. Fifty pts did not receive treatment and had no SPM reported. A total of 74 of the 1443 treated pts (5.1%) reported SPM. Invasive SPM were observed in 51 pts (3.5%): 37 pts (2.6%) with solid tumors and 14 pts (1.0%) with hematologic SPM. Lung/bronchus and myelodysplastic syndromes were the most frequently reported solid tumor and hematologic SPM respectively. NMSC were reported for 26 pts (1.8%). 3 pts had both an invasive SPM and NMSC. The IRs for invasive, hematologic, and solid tumor SPM by LEN exposure are listed in Table 1. By multivariate analysis, the only significant risk factor for the occurrence of SPM was prior history of invasive malignancy. Demographics (including age, ethnicity, race, and gender), International Staging System stage, family history of myeloma or other cancers, history of smoldering MM or monoclonal gammopathy of unknown significance, or prior radiation therapy were not associated with the occurrence of SPM.

Conclusions: This analysis shows that there was no increased risk of invasive SPM in this disease-specific registry of pts with NDMM. The risk of SPM for LEN exposed pts was not greater than that for pts not exposed to LEN. In addition, multivariate analysis indicated the only significant risk factor for SPM was prior history of invasive malignancy. As additional agents are approved for the treatment of MM and the length of pt survival increases, longer prospective observation with expanded enrollment on the registry will better characterize the occurrence of SPM in this pt population. Correlations with risk factors including age, pre-existing MDS, risk status, as well as type and duration of therapy will continue to be investigated.

^a PY of exposure is the sum of exposure of all pts.