Unfortunately we know that the recurrence rate for head and neck cancer can be high, up to 30-50% in some series. These recurrences tend to occur within the first two years following treatment. Optimal surveillance strategies to detect recurrences early and allow successful salvage treatment include the utilisation of PET-CT. However the best timing of scanning is unclear; too early can result in false negative and false positive interpretations. This retrospective study explored the question of the timing of the post-treatment PET-CT scan by examining the scans of a heterogeneous cohort of patients treated with primary CRT or surgery with or without adjuvant treatment. Scans were requested at the oncologist’s preference at the time and retrospectively put into groups: < seven weeks, seven to 10 weeks (majority of patients due to the institution’s imaging timing preference), 11 to 14 weeks and >15 weeks.
It was found that scans performed before week seven were less accurate; however there were no differences in the accuracy of the other groups’ imaging independent of treatment modality.
This paper raises the possibility of a two-month post treatment PET-CT scan being optimal for head and neck cancer patients.