A simulation model of colorectal cancer surveillance and recurrence

Table 2 Comparison of calibration group and validation group based on intensive and minimal follow-up groups, respectively, from trial by Pietra et al.[52]

Value	Calibration group (Intensive follow-up)	Validation group (Minimal follow-up)
Group characteristics
Number of subjects	104	103
Male	56%	51%
Mean age at diagnosis	62.2 +/− 11	64.4 +/− 12
Astler-Coller stage B/C	59.6%/40.4%	58.3%/41.7%
Primary colon/rectal tumors	70.2%/29.8%	64.1%/35.9%
Preoperative complications	14%	11%
Recurrence rate during study period	39.4%	40.4%^a
Distribution of metastatic disease if present: Liver/Lung/Other (includes multiple organs)^b	26.7%/0.0%/73.3%	14.2%/4.8%/81.0%
Surveillance testing schedule
Clinical interview/exam	Every 3 months for 2 years; every 6 months thereafter	Every 6 months for 1 year; every 12 months thereafter
CEA	Every 3 months for 2 years; every 6 months thereafter	Every 6 months for 1 year; every 12 months thereafter
Hepatic ultrasound	Every 3 months for 2 years; every 6 months thereafter	Every 6 months for 1 year; every 12 months thereafter
CT of abdomen/pelvis	Every 12 months	None
Chest x-ray	Every 12 months	Every 12 months
Colonoscopy	Every 12 months	Every 12 months
Outcome targets
Disease-free survival at 5 years (DFS5)	68%	53%
Overall survival at one year after initial surgery (OS1)	97%	98%
OS2	90%	89%
OS3	84%	74%
OS4	76%	65%
OS5	73%	58%
Proportion undergoing curative salvage re-operation for recurrence	20%	6%

CEA = serum carcinoembryonic antigen assay; OSx = overall survival at x years.
^aIncludes a single metachronous (new primary) CRC
^bMetastatic site was only reported by Pietra et al. for patients whose recurrences were metastatic only, and did not feature simultaneous involvement around the original tumor site.

ISSN: 1472-6947