CESA

CESA is a small Shiny application for analysing Caenorhabditis elegans survival experiments recorded as daily death counts. It expands the count table to individual observations, draws Kaplan–Meier curves, and compares each experimental group with the first (reference) group using a log-rank test.

Input format

Paste a tab-separated table into the app. Spreadsheet cells can be copied and pasted directly. The table must follow these rules:

• The first row contains unique column names.
• The first column contains non-negative numeric days, with one row per day.
• Every remaining column is an experimental group and contains the number of deaths observed on that day.
• Death counts must be non-negative whole numbers. Blank cells are treated as zero.
• The first group is the reference for pairwise p-values and percent lifespan change.

day	CT	TR
16	1	0
17	1	0
18	0	0

This count-table format records deaths only. If an experiment includes censored animals, convert it to individual-level time and event data before analysis; the current interface does not infer censoring from the count table.

Results

After selecting Analyse data, the app displays:

• mean lifespan with standard error of the mean (SEM), median lifespan, sample size, pairwise log-rank p-value, and percent lifespan change;
• Kaplan–Meier survival curves with a responsive 4:3 plot area;
• a PDF plot exported at 180 × 120 mm (3:2);
• one .xlsx workbook containing separate Individual data and Summary worksheets. Column widths, a frozen header row, filters, and header styling are included for convenient use in Excel.

For two-group analyses, the plot displays the log-rank p-value. With more than two groups, pairwise p-values against the first group remain available in the summary table.

Run locally

Required R packages: shiny, survival, and ggplot2. Excel export uses the system zip utility and does not require an additional R package.

shiny::runApp()

Live app: https://bioquest.shinyapps.io/cesa/