Contrast-enhanced CT scan and 18FDG-PET are used in the staging and surveillance of colorectal cancer (CRC). We here evaluate the feasibility of combined FDG-PET/contrast-enhanced CT in one diagnostic session in the diagnostic of recurrent colorectal cancer.45 patients underwent planned 159 procedures. 109 (68%) were performed as a combined modality in a single session and 50 were planned as two separate procedures at different times. Fourteen patients experienced recurrence during the study period. Sensitivity of 18FDG-PET scan and contrast-enhanced CT scan in detecting a recurrent disease was 84.4% and 86.6 % respectively with a specificity of 96% and 97% respectively. FDGPET and contrast-enhanced CT findings were concordant in 79% of cases. The overall sensitivity and specificity in detecting CRC recurrence were 80% and 99% respectively in the combined procedure and 89% and 98% respectively in the two-time procedure. The positive predictive value of the procedure (combined or two-time procedure) for detection of recurrent CRC was 100% with, however a shorter delay for decision with the combined [7.7vs 12.2 days] (p<0.05).
The combined procedure is feasible in almost 2/3 of cases. When compared to the two-time procedure, it is performant in detecting recurrent CRC with shorter delay to therapy.
PET; CT; 18FDG; Colon; Cancer