Utilisation of PET-CT Following Chemoradiation for Locally Advanced Head and Neck Cancer.


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Mark Winton1,Joanna Mackenzie1,Devraj Srinivasan1,Martin Doak1
1NHS Lothian

Abstract

Background

The recent PET-NECK study showed similar survival outcomes in PET-CT-guided active surveillance vs. planned neck dissection in locally advanced head and neck cancer. Routine PET surveillance post chemoradiotherapy (CRT) has been widely adopted following PET-NECK but does not form part of our routine local practice. Our utilisation of PET in the post CRT period is the subject of this study.

Method

All patients who were initially treated with concurrent chemoradiation at the Edinburgh Cancer Centre (2013-2017) had a routine post-treatment CT scan 3 months after treatment. Those patients with equivocal findings on CT went on to have FDG-PET and are the subject of this analysis.

Results

94 patients with equivocal post-treatment CT were identified. Of these 94 patients, 40% (n = 38) had a negative PET scan with 60% (n = 56) having a positive PET scan. 

30 of the 38 patients (79%) with a negative PET scan remain alive with no evidence of recurrence. 5 of 38 (13%) have had disease recurrence, 2 (5%) died with no documented cause and 1 was lost to follow up. Of the 5 with disease recurrence, 2 are alive, 1 died due to recurrent disease & 2 died with no documented cause.  

14 of the 56 patients (25%) with a positive PET scan went on to have a neck dissection, 10 of these (71%) showed no residual cancer, 4 (29%) had a positive neck dissection. The remaining 42 (75%) with positive PET scan did not proceed with neck dissection due to concerns about residual primary disease (n=20), distant metastasis (n=12) and new separate primary (n=10). 

Conclusion

Patients with positive post treatment PET scan in the neck frequently do not have residual cancer on neck dissection. PET scan may also alter post CRT neck management by detection of distant or residual primary disease.