Study: FDG PET/CT valuable in staging and followup of anal carcinoma

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FDG PET/CT is an accurate imaging modality during post-treatment followup, especially when persistence or recurrence of disease is suspected in anal cancer, according to a study published online Nov. 9 in the International Journal of Colorectal Disease.

The purpose of the study was to assess the diagnostic performance of FDG PET/CT for the staging and the followup of anal carcinoma, and to evaluate the impact of FDG PET/CT on patient management, wrote Laetitia Vercellino, MD, and colleagues from the nuclear medicine department at Hôpital Tenon et Université Pierre et Marie Curie in Paris.

Patients with anal carcinoma referred to nuclear medicine department, Hôpital Tenon et Université Pierre et Marie Curie, Paris from October 2004 until July 2008 were included in the study. The diagnostic performance was evaluated by Vercellino and colleagues on a per-exam basis and on a per-site basis, together with impact of PET/CT on patient management.

The standard of truth was histology when available and, in all cases, follow-up data during at least six months. Fifty-eight FDG PET/CT performed in 44 patients were analyzed. Out of the 58 FDG PET/CT performed, 22 were for initial staging and 36 were during follow-up. The detection rate of non-excised tumors on initial examination was 93 percent.

“During post-treatment follow-up, FDG PET/CT had, on a per-examination basis, sensitivity for the detection of persistent or recurrent disease of 93 percent and specificity of 81 percent, and on a per-site basis, 86 percent and 97 percent, respectively,” according to Vercellino and colleagues.

The negative predictive value for FDG PET/CT was 94 percent on a per-examination basis and 98 percent on a per-site basis.

FDG PET/CT had an impact on management in 20 percent of the patients, which was relevant in 89 percent of them. Further studies are needed to evaluate whether surveillance by means of FDG PET/CT might have a positive impact on overall survival, concluded Vercellino and colleagues.