Patients with colorectal cancer with liver metastases undergo hepatic resection with curative intent.
Positron emission tomography combined with computed tomography (PET-CT) could help avoid noncurative surgery by identifying patients with occult metastases.
Dr Carol-Anne Moulton and colleagues from Canada determined the effect of preoperative PET-CT vs no PET-CT (control) on the surgical management of patients with resectable metastases.
The team investigated the effect of PET-CT on survival and the association between the standardized uptake value, and survival.
The team conducted a randomized trial of patients older than 18 years with colorectal cancer treated by surgery, with resectable metastases based on CT scans of the chest, abdomen, and pelvis within the previous 30 days, and with a clear colonoscopy within the previous 18 months between 2005 and 2013.
The trial involved 21 surgeons at 9 hospitals in Ontario, Canada, with PET-CT scanners at 5 academic institutions.
|Liver resection was performed in 91% of patients in the PET-CT group|
|Journal of the American Medical Association|
Patients were randomized using a 2 to 1 ratio to PET-CT or control.
The researchers' primary outcome was a change in surgical management defined as canceled hepatic surgery, more extensive hepatic surgery, or additional organ surgery based on the PET-CT.
Survival was a secondary outcome.
Of the 263 patients who underwent PET-CT, the team noted that 21 had a change in surgical management.
Specifically, 3% of patients did not undergo laparotomy, 2% had more extensive hepatic surgery, 3% had additional organ surgery, and the abdominal cavity was opened in 1 patient but hepatic surgery was not performed, and the cavity was closed.
The team observed that liver resection was performed in 91% of patients in the PET-CT group, and 92% of the control group.
After a median follow-up of 36 months, the estimated mortality rate was 11 events per 1000 person-months for the PET-CT group, and 13 events per 1000 person-months for the control group.
The team noted that survival did not differ between the 2 groups.
The researchers found that standardized uptake value was associated with survival.
The C statistic for the model including the standardized uptake value was 0.62, and without it was 0.50.
The difference in C statistics is 0.12.
The team report that a low C statistic suggests that the standard uptake value is not a strong predictor of overall survival.
Dr Moulton's team concludes, "Among patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of PET-CT compared with CT alone did not result in frequent change in surgical management."
"These findings raise questions about the value of PET-CT scans in this setting."