Treatment patterns · Reporting

Treatment-Pathway Sunburst

A radial alternative to the Sankey: concentric rings encode successive lines of therapy, with wedge angle proportional to the share of patients on each path.

Download SVG Open code and full worked example

When to use it

To summarize sequential treatment shares when the hierarchy (1L → 2L → 3L) is the focus and you want a compact, single-glance overview. Prefer the Sankey when flows between specific therapies (who switches to what) matter more than nested proportions.

How to read it

The inner ring is first line; each outer ring subdivides its parent by what came next. Wedge angle is patient share; reading outward traces the most common pathways. Thin wedges are rare paths — label only the ones large enough to read.

Worked example

1000 patients start first-line (600 Drug A, 400 Drug B); the outer ring splits each first-line group by its second-line therapy (switch, stay, or stop), with wedge angle proportional to patient count.

Drug A → {Drug B 230, Drug C 150, Stop 220}; Drug B → {Drug B 90, Drug C 100, Stop 210}. Same data as the Sankey example.

Result: The inner ring is 60% Drug A / 40% Drug B; reading outward, the largest single pathway is Drug A → Drug B (230/1000 = 23%), and 430/1000 (43%) reach 'Stop' by second line — the same totals as the Sankey, shown as nested proportions.

Produced by

Treatment patterns / lines of therapy Switching, add-on & augmentation

Reference: Gatto NM, Wang SV, Murk W, et al. Visualizations throughout pharmacoepidemiology study planning, implementation, and reporting. Pharmacoepidemiol Drug Saf. 2022;31(11):1140-1152.