Effect of early detection of recurrent disease by FDG PET/CT on management of patients with squamous cell cancer of the head and neck (HNSCC).

Abstract

6062 Background: Despite the increasing cure rates a substantial fraction of HNSCC patients (pts) will present with locoregional and/or distant relapse within 3 years of definitive therapy. The prognosis of HNSCC pts after failure of first-line therapy has been poor but recent changes in the biology of HNSCC, advances in surgical techniques and radiotherapy; and new drugs may lead to improved salvage therapy. Notably, the success of these developments are implicitly dependent on early diagnosis disease. Our objective was to compare the efficacy of surveillance FDG-PET/CT to that of high resolution CT (HRCT) and physical exam (PE/E) for detection of early relapse in HNSCC after completion of primary treatment. Methods: A retrospective analysis of FDG-PET/CT, neck HRCT and PE/E was performed in 99 curatively treated HNSCC pts during post-therapy surveillance (PTS) to compare the performance characteristics of the tests in the detection of early recurrence or metachronous cancer. Results: A total of 19/99 (20%) pts had recurrence during a median follow-up of 21mo (range:9-52). Median time to first PET/CT was 3.5mo. The median time to radiological recurrence was 6 mo (range:2.3-32). PET/CT detected more disease recurrences or second primaries and did so earlier than HRCT and PE/E. Sensitivity, specificity, PPVand NPV for detecting locoregional and distant recurrence or metachronous cancer : 100%, 87.3%, 56.5% and 100% for PET/CT vs. 61.5%, 94.9%, 66.7% and 93.8% for HRCT vs. 23.1%, 98.7%, 75% and 88.6% for PE/E. In all 19 pts with a true positive PET/CT there was a significant management change prompting either salvage or definitive surgery or initiation of systemic therapy. Of the 14 recurrent pts treated with curative intent, 11 were alive with no evidence of disease at a median follow up of 31.5 mo. Conclusions: FDG-PET/CT has a high sensitivity in the early detection of relapse or second primary cancer in HNSCC, associated with significant management implications. Given improvements in therapy and changes in HNSSC biology, appropriate modifications in the current recommended algorithms of the NCCN for PTS may be required to engage effective salvage or definitive therapies.