Risk of multiple myeloma and other malignancies among first‐ and second‐degree relatives of patients with multiple myeloma: A population‐based study

Objectives We conducted a population‐based study to assess the risk for multiple myeloma (MM) and other cancers in first‐ and second‐degree relatives of MM patients, and to investigate whether evidence of anticipation is present in familial MM. Methods We retrieved 24 845 first‐degree relatives and 41 008 second‐degree relatives of 7847 MM patients, and 86 984 first‐degree relatives, and 138 660 second‐degree relatives of 26 511 matched controls. A Cox model was used to assess the risk for MM and other cancers in relatives of MM patients. Anticipation was assessed by a Cox model, where all parents and offspring of MM patients were included in the risk set. Results In second‐degree relatives of MM patients, no overall significant association with an MM diagnosis was observed (HR 1.99; 95%CI:0.86–4.57). In parents and offspring of MM patients, we found no significant difference in the ages at onset of MM (HR 1.28;95% CI:0.50–3.28). In affected parent‐offspring pairs, we observed no statistically significant difference in overall survival between the generations (HR 0.74; 95%CI:0.20–2.69). Conclusions Overall, second‐degree relatives of MM patients were not associated with an increased risk for MM. Our study supports that genetic anticipation is not present in familial MM.