[Clinical Features and Prognosis of Multiple Myeloma Patients with Secondary Primary Malignancies].

Objective: To explore the clinical characteristics and prognosis of multiple myeloma(MM) patients with secondary primary malignancies.

Methods: The clinical data of newly diagnosed MM patients admitted to the First Affiliated Hospital of Zhengzhou University from January 2011 to December 2019 were retrospectively analyzed. The patients with secondary primary malignancies were retrieved, and their clinical features and prognosis were evaluated.

Results: A total of 1 935 patients with newly diagnosed MM were admitted in this period, with a median age of 62 (18-94) years old, of which 1 049 cases were hospitalized twice or more. There were eleven cases with secondary primary malignancies (the incidence rate was 1.05%), including three cases of hematological malignancies (2 cases of acute myelomonocytic leukemia and 1 case of acute promyelocytic leukemia) and eight cases of solid tumors (2 cases of lung adenocarcinoma, and 1 case each of endometrial cancer, esophageal squamous cell carcinoma, primary liver cancer, bladder cancer, cervical squamous cell carcinoma, and meningioma). The median age of onset was 57 years old. The median time between diagnosis of secondary primary malignancies and diagnosis of MM was 39.4 months. There were seven cases with primary or secondary plasma cell leukemia, the incidence rate was 0.67%, and the median age of onset was 52 years old. Compared with the randomized control group, the β2-microglobulin level in the secondary primary malignancies group was lower (=0.028), and more patients were in stage I/II of ISS (=0.029). Among the 11 patients with secondary primary malignancies, one survived, ten died, and the median survival time was 40 months. The median survival time of MM patients after the secondary primary malignancies was only seven months. All seven patients with primary or secondary plasma cell leukemia died, with a median survival time of 14 months. The median overall survival time of MM patients with secondary primary malignancies was longer than that of the patients with plasma cell leukemia (=0.027).

Conclusion: The incidence rate of MM with secondary primary malignancies is 1.05%. MM patients with secondary primary malignancies have poor prognosis and short median survival time, but the median survival time is longer than that of patients with plasma cell leukemia.