Prognostic value of 18-fluorodeoxyglucose positron emission tomography-computed tomography in resectable colorectal cancer

Abstract

Aim: To assess the prognostic value of preoperative 18 fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) in patients with resectable colorectal cancer.

Methods: One hundred sixty-three patients with resectable colorectal cancer who underwent FDG-PET/CT before surgery were included. Patient data including pathologic stage at presentation, histology, treatment, disease-free survival and the maximum standardized uptake value (SUVmax) of the primary tumor on FDG-PET/CT were retrospectively analyzed. Median follow up duration was 756 (range, 419-1355). The primary end point was disease-free survival.

Results: Twenty-five of 163 patients (15.3%) had recurrences. The median SUVmax values of the recurrence and no-recurrence groups were 8.9 (range, 5-24) and 8.2 (range, 0-23, P = 0.998). Receiver operating characteristic (ROC) curve analysis showed no significant association between SUVmax and recurrence (area under the curve = 0.5, P = 0.998, 95% CI: 0.389-0.611). Because a statistically significant value was not found, SUVmax was dichotomized at its median of 8.6. The disease-free survival curve was analyzed using the median SUVmax (8.6) as the cut off. Univariate and multivariate analysis did not provide evidence that disease-free survival rates for the subgroups defined by the median SUVmax were significantly different (P = 0.52, P = 0.25).

Conclusion: Our study suggests that the high FDG uptake of primary mass in resectable colorectal cancer doesn't have a significant relationship with tumor recurrence and disease-free survival.

Keywords: Colorectal neoplasms; Disease-free survival; Positron-emission tomography; Prognosis; Recurrence.

Figure 1

Receiver operating characteristic curve for prediction of recurrence from the maximum standardized uptake value. AUC: Area under curve.

Figure 2

Receiver operating characteristic curves for prediction of recurrence from the maximum standardized uptake value and subgroup analysis according to stage. A: Subgroup analysis according to stage II; B: Subgroup analysis according to stage III; C: Subgroup analysis according to stage IV. AUC: Area under curve.

Figure 3

Disease-free survival according to the maximum standardized uptake value. SUVmax: Maximum standardized uptake value.