To the Editor Dr Moulton and colleagues¹ concluded that positron emission tomography (PET) combined with computed tomography (CT) compared with diagnostic CT alone did not significantly change the management of patients with potentially resectable metastatic colorectal adenocarcinoma. However, we are concerned about some issues related to the use of PET-CT.

The study used PET-CT primarily for restaging because more than 70% of the patients received adjuvant chemotherapy prior to presurgical staging.¹ However, comparison with an initial staging PET is important when deciding on therapy and assessing treatment response. Moulton et al¹ described how their results differed from other studies,^2,3 but those studies performed baseline PET imaging before any adjuvant therapy.