[Analysis of the characteristics of second primary malignancy affecting the survival of lymphoma patients]

Objective: To analyze the characteristics of the second primary tumor affecting the survival of patients with lymphoma, and to explore the risk factors of death from the second primary tumor. Methods: The medical records and related death information of 1 173 lymphoma patients who had already died with known causes were collected. The basic causes of death and the characteristics of patients who died of the second primary tumor were analyzed. Cox regression model was used to analyze the risk factors of lymphoma patients who died of the second primary tumor. Results: Among the 1 173 patients who had died, 94 (8.0%) died of the second primary tumor, 935 (79.7%) died of the primary lymphoma and 144 (12.3%) died of other diseases. The second primary tumor accounted for 17.5% (38/217) of all causes of death in patients with the survival period of more than 5 years, and the second primary tumor accounted for 28.3% (17/60) of all causes of death in patients with the survival period of more than 10 years. Among 94 cases who died of second primary tumors, 31 died of lung cancer, 15 died of gastric cancer, 13 died of liver cancer, 9 died of pancreatic cancer, 6 died of colorectal cancer, 6 died of second primary lymphoma and 14 died of other types of tumors. Univariate Cox regression analysis showed that age, first-line treatment effect, and chest or mediastinal radiotherapy were associated with the death from second primary tumors for lymphoma patients (all P<0.05). Multivariate Cox regression analysis showed that the effect of first-line treatment (P=0.030) and the chest or mediastinal radiotherapy (P=0.039) were independent factors for the death of lymphoma patients from the second primary tumor. Conclusions: The second primary tumor is an important factor affecting the survival of lymphoma patients, and the risk of death from second primary tumors increases significantly over time. The effect of first-line treatment and radiotherapy in the chest or mediastinum are independent factors for the death of lymphoma patients from the second primary tumor.