BACKGROUND: Very few reports are available on the incidence and risk of second primary cancers in nasopharyngeal carcinoma (NPC) cases, and most of these are single-institution reviews with relatively small case numbers and short follow-up. PATIENTS AND METHODS: A population-based study was conducted. We quantified standardized incidence ratios (SIRs) and cumulative incidence of second cancers among 23 639 individuals with initial diagnoses of NPC. RESULTS: We found a 24% increased risk of second cancers in NPC patients compared with the general population [SIR = 1.24, 95% confidence interval 1.15-1.33]. Elevated SIRs were observed in the following second primary cancers: oral/pharyngeal, salivary gland, sarcoma, skin and leukemia/lymphoma. The cumulative incidence >10 years was 3.26%. The risk was higher in younger patients, especially those <40 years old. After diagnosis of second cancers, the median survival time was 1.7 years. CONCLUSIONS: This is the largest population-based study to date from a high-incidence area. We found that NPC is associated with an increased risk of second malignancies, which had a negative impact on the survival of patients who survived NPC.
BACKGROUND: Very few reports are available on the incidence and risk of second primary cancers in nasopharyngeal carcinoma (NPC) cases, and most of these are single-institution reviews with relatively small case numbers and short follow-up. PATIENTS AND METHODS: A population-based study was conducted. We quantified standardized incidence ratios (SIRs) and cumulative incidence of second cancers among 23 639 individuals with initial diagnoses of NPC. RESULTS: We found a 24% increased risk of second cancers in NPC patients compared with the general population [SIR = 1.24, 95% confidence interval 1.15-1.33]. Elevated SIRs were observed in the following second primary cancers: oral/pharyngeal, salivary gland, sarcoma, skin and leukemia/lymphoma. The cumulative incidence >10 years was 3.26%. The risk was higher in younger patients, especially those <40 years old. After diagnosis of second cancers, the median survival time was 1.7 years. CONCLUSIONS: This is the largest population-based study to date from a high-incidence area. We found that NPC is associated with an increased risk of second malignancies, which had a negative impact on the survival of patients who survived NPC.