Safety and cost analysis of an (18)FDG-PET-CT response based follow-up strategy for head and neck cancers treated with primary radiation or chemoradiation.

Background: Prognostic information can rationalise clinical follow-up after radical cancer treatment. This retrospective cohort study of radical head and neck (chemo)radiotherapy patients examines the clinical safety and cost implications of stratifying follow-up intensity by post-treatment (18)FDG-PET-CT response.

Methods: In 2008 clinical review after radical head and neck radiotherapy was reduced from 3- to 6-monthly for patients with complete (18)FDG-PET-CT response at 3months. 184 patients treated after this change ("PET Stratified", 2009-11) were compared to 178 patients treated before ("Standard", 2005-7). Clinical safety was assessed by the time to detection of recurrence, overall survival and potential for radical treatment of recurrence. A hospital cost analysis was performed using individual patient data.

Results: 127 of 178 Standard and 148 of 184 PET Stratified patients achieved complete response on post-treatment imaging. Baseline clinical characteristics were comparable. Median follow-up from response assessment was 4.8years in the Standard cohort and 2.1years for PET Stratified. PET Stratified patients had a mean 4.4 outpatient visits in 2years, compared to 7.0 among Standard patients. Over 90% of patients remained free of recurrence at 2years in both cohorts. Time to detection of recurrence was similar between two cohorts (HR1.05, 95%CI 0.45-2.52), as was overall survival (HR0.91, 95%CI 0.36-2.29). The proportion of radically treatable recurrences was also similar (42% Standard vs. 47% PET Stratified). The hospital cost savings per patient from reduced review were AUD$2606 over 2years, AUD$5012 over five.

Conclusion: (18)FDG-PET-CT to stratify follow-up intensity after radical radiotherapy for head and neck cancer reduces costs with no apparent clinical detriment.