A number of new treatments for patients with multiple myeloma (MM) have become available in recent years, enabling patients to live longer. Unfortunately, these patients are susceptible to developing another malignancy later in life, particularly if they were diagnosed with a malignancy prior to MM diagnosis.
In an analysis of data from the Swedish Cancer Registry, which collects information about all reported malignancy diagnoses since 1958, Gudbjörg Jonsdottir, MD, from the University of Iceland in Reykjavik, and co-authors assessed susceptibility to subsequent cancers and survival in nearly 20,000 patients diagnosed with MM. Results were published in Blood Advances.
The study included 19,791 people who were diagnosed between January 1, 1973, and December 31, 2010; 2,469 patients (12.5%) had at least one prior malignancy diagnosis at the time of MM diagnosis, while the remaining 17,322 (87.5%) did not. The most common types of prior malignancies were male reproductive cancer (n=427; 17.3%), female reproductive cancer (n=401; 16.2%), and breast cancer (n=329; 13.3%).
Subsequent malignancies were developed by 216 (8.8%) of the 2,469 patients with prior malignancies, and by 1,257 (7.3%) if the 17,322 patients without prior malignancies.
“A prior malignancy diagnosis in [patients with] MM was associated with a 40 percent increased risk of developing a subsequent malignancy, [compared with patients without prior malignancy],” the authors reported (hazard ratio [HR] = 1.42; 95% CI 1.23-1.65; p<0.001). The risk was greater across all types of malignancies, including hematologic cancers, malignant melanoma, non-melanoma skin cancer, and malignancies of the respiratory tract (see TABLE for all outcomes).
“These patients developed their subsequent malignancy almost a year sooner than those without a history of prior malignancy,” the researchers added. The median time from first prior malignancy to MM diagnosis was 7.1 years (range not provided) in both those who did and did not develop a subsequent malignancy (p=0.732). These patients developed a first subsequent malignancy at a median of 2.3 years after diagnosis (range = 0.02-21.5 years), compared with 3.2 years (range = 0.003-37.5 years) among those who did not have a prior malignancy (p=0.003).
Risk of death was also increased among people diagnosed with a malignancy before MM (HR=1.21; 95% CI 1.15-1.26; p<0.001). In a “dose-response” analysis, the researchers observed that the risk appeared to increase with the number of prior malignancies: Patients with two or more prior malignancies had a 34 percent increased risk of death (HR=1.34; 95% CI 1.19-1.52; p<0.001), compared with those without prior diagnoses.
These results “might suggest inherent genetic susceptibility in these patients,” the authors wrote. However, because genetic profiles were unavailable for all patients in this registry, the study was not able to examine that association. “Other possible etiologies include immune dysfunction … or side effects from treatment,” they noted, adding that further research is needed.
The study is limited by the reliance on a registry, which lacked clinical and treatment data, including cause of death and the pathologic stage of prior cancers, myeloma, and subsequent cancers.
The authors report no financial conflicts.
Jonsdottir G, Lund SH, Björkholm M, et al. The impact of prior malignancies on second malignancies and survival in MM patients: a population-based study. Blood Advances. 2017 November 28.