FDG PET/CT evaluation of treatment response in patients with recurrent colorectal cancer.

AIM: to evaluate the treatment response in patients with recurrent colorectal cancer (CRC) using FDG PET/CT. MATERIALS AND METHODS: a total of 32 recurrent CRC patients (21 males, 11 females; mean age, 52.8 years) were included in this retrospective study. All patients underwent a baseline and follow-up FDG PET/CT scans after chemotherapy. Of 32 patients, 23 patients had follow-up carcinoembryonic antigen (CEA) levels. RESULTS: on qualitative analysis of baseline and follow-up FDG PET/CT studies, there were 20 nonresponders and 12 were responders. On quantitative analysis, there were 19 nonresponders and 13 were responders. In responders, baseline and follow-up mean SUV(max) were 11.8 ± 10.1 and 3.7 ± 4.1, respectively (significant decrease, P = 0.001). Among nonresponders, baseline and follow-up mean SUV(max) were 8.1 ± 5.2 and 14.1 ± 9.0, respectively (significant increase, P = 0.003). There was no association between response and different factors like age, sex, diagnosis, extent of the lesions, and number of lesions. CONCLUSION: FDG PET/CT appears to be useful modality in evaluating chemotherapy response and can differentiate responders from nonresponders in recurrent CRC patients.