Risk-dependent curability of radiotherapy for elderly patients with early-stage extranodal nasal-type NK/T-cell lymphoma: A multicenter study from the China Lymphoma Collaborative Group (CLCG)

Background The purpose of this study was to determine the curability of early-stage extranodal nasal-type NK/T-cell lymphoma (NKTCL) in response to radiotherapy and non-anthracycline-based chemotherapy in elderly patients. Methods In this multicenter study from the China Lymphoma Collaborative Group (CLCG) database, 321 elderly patients with early-stage NKTCL were retrospectively reviewed. Patients received radiotherapy alone (n = 87), chemotherapy alone (n = 59), or combined modality therapy (CMT, n = 175). Patients were classified into low- or high-risk groups using four prognostic factors. Observed survival in the study cohort vs expected survival in age- and sex-matched individuals from the general Chinese population was plotted using a conditional approach and subsequently compared using a standardized mortality ratio (SMR). Results Radiotherapy conveyed a favorable prognosis and significantly improved survival compared to chemotherapy alone. The 5-year overall survival (OS) and progression-free survival (PFS) were 61.2% and 56.4%, respectively, for radiotherapy compared with 44.7% and 38.3%, respectively, for chemotherapy alone (P 0.001). The combination of a non-anthracycline-based chemotherapy regimen and radiotherapy significantly improved PFS compared to combination of an anthracycline-based chemotherapy regimen and radiotherapy (71.2% vs 44.2%, P = 0.017). Low-risk patients following radiotherapy (SMR, 0.703; P = 0.203) and high-risk patients who achieved PFS at 24 months (SMR, 1.490; P = 0.111) after radiotherapy showed survival equivalent to the general Chinese population. Conclusions Our findings indicate a favorable curability for this malignancy in response to radiotherapy and non-anthracycline-based chemotherapy, providing a risk-adapted follow-up and counsel scheme in elderly patients.