Prognostic Values of Pre- and Post-Therapeutic FDG-PET in Anal Canal Cancer: Analysis of a Prospective Study.

Background: The aim of this post hoc study was to assess the prognostic value of 18F-FDG PET/CT quantitative parameters recorded before and after treatment for anal canal neoplasm for the disease free survival.

Materials and methods: Consecutive, previously untreated patients with histologically proved anal cancer, with 18F-FDG PET/CT pre- and 2 months post treatment were included. The following criteria were analyzed: baseline primary tumor lesion glycolysis (TLG), metabolic tumor volume (MTV), standardized tumor volume (SUV) max and mean, SUV normalized by lean body mass (SUL) max, mean and peak, variations between pre- and post-treatment examinations for SUVmax (Delta SUVmax), TLG (Delta TLG), MTV (Delta MTV), as well as post-treatment SULpeak and SUVmax for the primary tumor, and baseline sum of lesions TLG and MTV.

Results: About 78 consecutive patients were included in this study. Median follow-up was 49 months. Baseline TLG, SUVmax, SULpeak, SULmax, sum of lesions for TLG and MTV, Delta SUVmax, and post-therapeutic SULpeak and SUVmax for the primary tumor, were statistically significant for disease free survival.

Conclusion: Pretherapeutic 18F-FDG PET/CT has a statistically significant prognostic value. The wide variability of results published in literature compels us to specifically explore the interest of uptake variations between pre- and post-treatment examinations.