Risk of second malignant neoplasms among long-term survivors of early stage extranodal nasal-type natural killer/T-cell lymphoma

Abstract

Objective To estimate risk and incidence of second malignant neoplasms (SMN) among long-term survivors of early stage extranodal nasal-type natural killer/T-cell lymphoma (NKTCL). Methods Between January 1983 and December 2007, 174 patients with stage ⅠE and ⅡE NKTCL survived 3 or more years after treatment. Of them, 50 patients were treated with radiotherapy alone, 120 patients with combined modality therapy, and 4 patients with chemotherapy alone. The China 2010 population census data and Segi's world population data were used for calculating the age-standardized cancer incidence rates. Results Median follow-up time was 8.3 years (3.1-35.6 years) for all patients. Nine (5.2 %) SMN were recorded. The median time to SMN was 12.6 years (0.9-18.5 years) from diagnosis of NKTCL. Seven patients had solid tumors, and 2 had other type of malignant lymphomas. The cumulative incidence rates at 5-year, 10-year and 15-year were 1.2 %, 2.4 % and 13.7 %, respectively. The crude incidence was 531.6/105 person-years, the age-standardized rates by Chinese standard population (ASR China) and world standard population (ASR world) were 294.5/105 and 243.7/105, respectively, and the cumulative incidence rate (0-74 years old) was 22.4 %. All of them were higher than the cancer incidence rates for general population in China in 2010. Conclusions A frequency of SMN in patients with NKTCL is higher than that expected in the general population. The patients have more risk for SMN during 10 to 15 years after diagnosis of NKTCL. Patients with long-term survival are at higher risk of SMN and should be carefully followed-up. Key words: Lymphoma, extranodal NK-T-cell; Second malignant neoplasm; Incidence rate