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.