PT - JOURNAL ARTICLE AU - Clémence Houard AU - Jean-Baptiste Pinaquy AU - Charles Mesguich AU - Bénédicte Henriques de Figueiredo AU - Anne-Laure Cazeau AU - Jean-Baptiste Allard AU - Hortense Laharie AU - Laurence Bordenave AU - Philippe Fernandez AU - Véronique Vendrely TI - Role of <sup>18</sup>F-FDG PET/CT in Posttreatment Evaluation of Anal Carcinoma AID - 10.2967/jnumed.116.185280 DP - 2017 Sep 01 TA - Journal of Nuclear Medicine PG - 1414--1420 VI - 58 IP - 9 4099 - http://jnm.snmjournals.org/content/58/9/1414.short 4100 - http://jnm.snmjournals.org/content/58/9/1414.full SO - J Nucl Med2017 Sep 01; 58 AB - The aim of this study was to evaluate the relevance of PET/CT and 18F-FDG as a strategy for response evaluation after chemoradiotherapy for anal cancer. For this, the performance of posttreatment 18F-FDG PET/CT, the impact on patient care, and the predictive value of metabolic response were assessed. Methods: This was a retrospective and multicenter analysis of 87 patients treated by chemoradiotherapy for anal squamous cell carcinoma between October 2007 and October 2013. All patients underwent systematic posttreatment 18F-FDG PET/CT and were followed with at least a clinical examination every 4 mo for 2 y and every 6 mo thereafter. Disease progression was confirmed by biopsy for all patients in the case of local recurrence before surgery. Kaplan–Meier and Cox regression models were used to test for associations between metabolic or clinical endpoints and progression-free survival (PFS) or cause-specific survival (CSS). Results: The median follow-up was 25 mo. 18F-FDG PET/CT was performed 1–8 mo (median, 4 mo) after completion of chemoradiotherapy. Overall, 25 patients relapsed and 13 died. The posttherapy 18F-FDG PET/CT did not show any abnormal 18F-FDG uptake (complete metabolic response [CMR]) in 55 patients whereas 32 displayed incomplete response (non-CMR): 15 patients with partial response and 17 with disease progression. The sensitivity of 18F-FDG PET/CT to detect residual tumor tissue was 92% (95% confidence interval [CI], 75%–97%), specificity was 85% (95% CI, 75%–92%), positive predictive value was 72% (95% CI, 61%–90%), and negative predictive value was 96.4% (95% CI, 90%–98.7%). The 2-y PFS was 96% (95% CI, 90–100) for patients with CMR and 28% (95% CI, 14–47) for non-CMR patients (P &lt; 0.0001). The 2-y CSS was 100% for patients with CMR and 59% (95% CI, 42–84) for those without CMR (P &lt; 0.0001). 18F-FDG PET/CT changed patient management in 14 cases (16%), with relevant modifications in 12 (14%). A Cox proportional hazards model of survival outcome indicated that a CMR was the only significant predictor of PFS and CSS (P &lt; 0.0001). Conclusion: 18F-FDG PET/CT shows good accuracy in posttreatment evaluation of anal cancer and has a relevant impact on patient management. Moreover, CMR is associated with good survival outcome. Thus, 18F-FDG PET/CT may play a significant role during posttreatment follow-up of anal cancer.