This study aimed to investigate transitions of recurrence hazard and peak recurrence time in patients with nonmetastatic CRC using the hazard function.
Summary of Background Data:
A postoperative surveillance period of 5 years is consistent across major guidelines for patients with nonmetastatic CRC, but surveillance intervals differ. Estimates of instantaneous conditional recurrence rate can help set appropriate intervals.
The study population consisted of 4330 patients with stage I to III CRC who underwent curative resection at the National Cancer Center Hospital between January 2000 and December 2013. Hazard rates of recurrence were calculated using the hazard function.
Recurrence rates in patients with stage I, II, and III CRC were 4% (50/1432), 11% (136/1231), and 25% (424/1667), respectively. The hazard curve for stage I was relatively flat and hazard rates were consistently low (<0.0015) for 5 years after surgery. The hazard curve for stage II had a peak hazard rate of 0.0046 at 13.7 months, after which the curve had a long hem to the right. The hazard curve for stage III had an earlier and higher peak than that of stage II (0.0105 at 11.6 months), with a long hem to the right.
Changes in recurrence hazard for CRC patients varied considerably by stage. Our findings suggest that short-interval surveillance might be unnecessary for stage I patients for the first 3 years after surgery, whereas short-interval surveillance for the first 3 years should be considered for stage III patients.