Background:The outcome of diffuse large B cell lymphoma (DLBCL) improved significantly, due to the addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) chemotherapy. However, significant range of patients showed relapse or refractory to R‐CHOP, and the role of body surface area (BSA) or body mass index (BMI) to overall survival (OS) was not known or still controversial.Aims:We evaluated effects of rituximab dose, BSA or BMI on OS using National Health Information Database.Methods:This study included patients 5,332 patients who were diagnosed with DLBDL and received R‐CHOP as a frontline therapy between 2006 and 2014. The exclusion criteria were as follows;1) age <20 years 2) R‐CHOP was given less than 4 times or over 8 times 3) R‐CHOP 2 months after diagnosis 4) Interval between two consecutive R‐CHOP injection was over 60 days. We extracted age, sex, prescribed medication list, and date of death from NHID. Weight and height of patients who had national general health examination before 1st cycle of R‐CHOP was collected.Results:Median age was 58(20–92) years, and 57%(n = 3021) of them were male. Thirty‐eight % of patients (n = 2019) received R‐CHOP 4–5 times, and 62% (n = 3303), 6–8 times. Median dose of injected rituximab was total 7200(1,600–16,800) mg, and median mean dose of rituximab per each cycle was 600(400–1,000) mg. A total 2,523 patients (47.4%) were treated at medical institution in capital (Seoul) area. About 72% of patients (n = 3813) had national health examination before chemotherapy. Their median weight and height were 63(31–121) kg and 163(131–196) cm, respectively. Median BSA and BMI were 1.69m2 and 23.9 kg/m2.With median 66(24–144) months of follow up, estimated 5‐year and 10‐year overall survival was 37.1% and 25.6% respectively. Log‐rank test for 10‐year OS, age≤60 (vs age>60), female (vs male), 6–8 times of R‐CHOP injection (vs 4–5 times of R‐CHOP), total R dose≥7200 mg (vs <7200), mean R dose≥600 mg, and medical institution in Seoul (vs others) were associated OS, significantly (p < 0.05). However, total R dose did not affect OS in multivariate analysis (p = 0.152).Among 3813 patients who had national health examination before R‐CHOP, patients whose BSA <1.69m2 had worse OS than BSA≥1.69m2. But BMI did not differentiate OS.Summary/Conclusion:With 66 (24–144) months of median follow up, estimated OS at 5‐year and 10‐year of DLBCL patients were 37.1% and 26.5%, respectively. Mean rituximab dose ≥600 mg showed better OS than <600 mg. High BSA showed favorable OS, but BMI did not affected OS significantly. image
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