2.5. Statistical Analyses

A response rate of primary therapeutic modalities, and the associated risk factors, OS, PFS, relapses and significant adverse events after each therapy were evaluated. OS was calculated from the date of initial diagnosis (time of biopsy) to the date of any cause of death or last follow-up, and PFS was defined as the period from the date of initial diagnosis until the time of the first progression, or last follow-up date, or the date of any cause of death, whichever occurred earlier. Time to best response (CR) was defined as the time from the date of treatment initiation to the date of the documented CR. Demographic and clinical characteristics were analyzed using the Student's t-test and chi-square test. Survival curves for OS and PFS were analyzed using the Kaplan–Meier method and compared to the log-rank test, and the Gray test used to analyze differences in the cumulative incidence curves of relapse incidences. To identify the risk factors for survival outcomes of OAML in our cohort, univariate and multivariate analyses were performed for the variables of age, sex, disease location, laterality, Ann Arbor stage, TNM stage, IPI score, BM involvement, Ki-67 index, and therapeutic modality. The prognostic significance of multivariate affecting therapy outcomes regarding OS, PFS, and relapse were determined using the Cox proportional hazard model with a variable of p ≤ 0.2 and hazard ratios (HRs) with 95% confidence interval (CIs) in univariate analyses. For all prognostic analyses, continuous variables were categorized and the median was used as a cut-off point. All interactions between each variable were investigated. Statistical significance was considered at a p-value < 0.05 of the two-tailed likelihood ratio test, and each estimate of the therapeutic methods was calculated with a 95% CI assuming an exact binomial distribution. All statistics were conducted using SPSS, version 20 (SPSS, Inc., Chicago, IL) and R-software (version 3.2.3, R Foundation for Statistical Computing, 2012, http://cran.r-project.org/).

This single-center retrospective study was approved by The Catholic Medical Center Institutional Review Board, and all of the analyses followed the Institutional Review Board guidelines and adhered to the Declaration of Helsinki.

The funders of the study had no role in the study design, data collection, data analyses, data interpretation, or writing of the report. Y.W. Jeon, and S.G. Cho had access to annotated patient clinical data. The corresponding author had full access to all of the anonymized results and final responsibility for the decision to submit for publication.