Number of prior and subsequent malignancies in MM patients according to malignancy types. Group letters: A, ear, nose, and throat; B, gastrointestinal; C, respiratory; D, bone and cartilage; E, melanoma; F, nonmelanoma skin cancer; G, soft tissue and mediastinal; H, breast malignancy; I, female reproductive; J, male reproductive; K, kidney and urinary tract; L, nervous system; M, endocrine; N, unspecified tumors; O, hematological; and P, eye tumors.