Spss statistics version 24.0.0 for windows

Data are reported as median [interquartile range (IQR) or 95% confidence interval] or mean ± standard deviation as appropriate. Categorical data are reported as count (%). The Kaplan–Meier method was used for survival analysis, and a log rank test was performed for comparison. The median follow-up period was calculated with the reversed Kaplan–Meier method. Overall survival was calculated from the day ILNM was diagnosed until death or the date of the last follow-up visit. Statistical analysis was performed using IBM SPSS Statistics version 24.0.0 for Windows (IBM Corp, Armonk, New York, USA).

Survival analysis was performed by Kaplan–Meier method, and comparisons were made using log-rank tests. Survival was calculated from day of APR until data of death or last follow-up. Survival rates for recurrence after salvage APR were calculated from date of diagnosis of recurrent anal SCC until death or last follow-up. Cox proportional-hazard models were constructed to identify prognostic factors in univariable and multivariable analysis. Mann–Whitney U and chi-squared test were performed as appropriate. Covariables with a trend towards significance (p < 0.100) were selected for multivariable analysis, with a maximum of three considering the number of events. Two-sided p-values < 0.05 were considered statistically significant. Statistical analysis was performed using IBM SPSS Statistics version 24.0.0 for Windows (IBM Corp, Armonk, New York, USA).