Statistical analysis

Patients were grouped according to whether pancreas protocol CT (PPCT) occurred before or after chemotherapy initiation. Surgery-related intervals and proportions were summarized only among patients with recorded surgery. Continuous variables were summarized as medians and interquartile ranges and compared between groups using two-sided Wilcoxon rank-sum tests. Analyses used available observations for each variable. P values less than 0.05 were considered statistically significant. All analyses were performed in R (version 4.3.1).

Cohort and available observations

Table 1: Patient counts by group and availability of surgery or follow-up information

Status	Pre-chemo PPCT	Post-chemo PPCT
No surgery; follow-up recorded	51	18
Surgery recorded	64	70

Table 2: Available observations for each measure

Measure	Available_Pre-chemo PPCT	Available_Post-chemo PPCT	Missing_Pre-chemo PPCT	Missing_Post-chemo PPCT
Initial study to PPCT	115	88	0	0
Initial study to PPCT / initial study to surgery	64	70	0	0
Initial study to surgery (surgical patients)	64	70	51	18
PPCT order to completion	106	86	9	2
PPCT order to completion / initial study to surgery	58	68	6	2
PPCT to surgery (surgical patients)	64	70	51	18

For proportions, missing counts refer only to surgical patients. For intervals, they refer to the full group; surgery-related intervals are not applicable to patients without recorded surgery.

Distributions and group comparisons

Boxplots show the median and interquartile range, with individual observations overlaid. All observed values are displayed; horizontal jitter only separates overlapping observations. Each interval panel has its own vertical scale. Proportions are shown as percentages among surgical patients with available data.

Figure 1: Observed time intervals by timing of PPCT relative to chemotherapy

Figure 2: Proportions of time from initial study to surgery, among surgical patients

Table 3 summarizes the median and interquartile range for each measure, along with the number of available observations. Wilcoxon rank-sum tests compare distributions between groups.

Table 3: Time intervals and proportions by PPCT group

Measure	Pre-chemo n	Pre-chemo median (IQR)	Post-chemo n	Post-chemo median (IQR)	P value
Initial study to PPCT (days)	115	13.0 (2.0–42.0)	88	114.5 (87.8–198.0)	<0.001
PPCT order to completion (days)	106	2.5 (0.0–8.0)	86	28.5 (20.2–42.0)	<0.001
PPCT to surgery (surgical patients) (days)	64	211.5 (177.5–238.0)	70	109.5 (36.0–139.2)	<0.001
Initial study to surgery (surgical patients) (days)	64	243.5 (191.0–263.8)	70	230.5 (207.8–265.5)	0.933
Initial study to PPCT / initial study to surgery (%)	64	8.5 (2.8–22.6)	70	56.9 (39.1–85.5)	<0.001
PPCT order to completion / initial study to surgery (%)	58	1.4 (0.0–3.3)	68	12.9 (8.6–18.2)	<0.001