Addition of ¹⁸F-FDG PET/CT to Clinical Assessment Predicts Overall Survival in HNSCC: A Retrospective Analysis with Follow-up for 12 Years

Abstract

18 F-FDG PET/CT is used in the follow-up of patients with head and neck squamous cell cancer (HNSCC). However, its impact on clinical decision making and patient outcome is not fully established. The objective of this study was to determine the prognostic value of 18 F-FDG PET/CT for overall survival (OS) of HNSCC patients when performed in addition to clinical assessment between 4 and 24 mo after treatment. Methods: This was a retrospective study at a single tertiary center. The institutional review board approved this study, and the requirement to obtain informed consent was waived. The study included 134 biopsy-proven HNSCC patients with 227 followup PET/CT scans. The primary outcome measure was OS. Median follow-up was 40 mo (range, 7-145 mo). Survival is presented as Kaplan-Meier plots with Mantel-Cox log-rank test. The multivariate Cox model included clinical covariates. Results: Of the 227 PET/CT scans, 41 (18%) were positive for tumor and 186 (82%) were negative for tumor. PET/CT identified recurrence in 5% (9/194) of scans performed without prior clinical concern and ruled out tumor in 51.5% (17/33) of scans performed to evaluate clinical suspicion or uncertainty of recurrence. The median survival of PET-positive and -negative groups from the date of the scan was 20 and 30.5 mo, respectively (P , 0.0001). There was a significant difference in OS from the scan date between patients who had a positive PET/CT result for tumor and those who had a negative result (log-rank, P , 0.0001), with a hazard ratio of 29.74. Human papillomavirus status (P 5 0.001) and PET/CT result (P 5 0.04) were the only factors significantly associated with OS, adjusted for all other covariates. Conclusion: 18 F-FDG PET/CT performed between 4 and 24 mo after treatment adds value to clinical assessment at the time of the study, especially when there is clinical suspicion or uncertainty, and can serve as a prognostic marker of OS in HNSCC.

18F-FDG PET/CT: Therapy Response Assessment Interpretation (Hopkins Criteria) and Survival Outcomes in Lung Cancer Patients

“…Previous studies also suggested that follow-up and surveillance PET/CT could add value to clinical assessment and excluded malignancy in about 50% and 15% of scans obtained with prior clinical suspicion, in head and neck cancer and lung cancer patients, respectively (26,27). This study further demonstrated the added value of therapy assessment PET/CT in lung cancer patients.…”

18F-FDG PET/CT and Lung Cancer: Value of Fourth and Subsequent Posttherapy Follow-up Scans for Patient Management

“…The scan results were dichotomized into positive for disease (positive interpretations) or negative for disease (negative and indeterminate interpretations). From our previous work in other cancers such as head and neck cancer, it was anticipated that most of the indeterminate scan results are true-negative for tumor and about 5% of the indeterminate scan results eventually become false-negative when these scans are classified as negative (18). Follow-up scans were further grouped as having been performed for routine surveillance or secondary to clinical suspicion of disease recurrence or metastases.…”

“…Patients with 2 concurrent primary cancers or with a second primary cancer were excluded from the study. Between January 2001 and October 2013, a total of 1,171 lung cancer patients who had been evaluated with 18 F-FDG PET/CT were identified from our PET center database, of whom 85 patients met our study inclusion criteria, providing a total of 285 follow-up PET/CT scans (range, 4-28 per patient). Only the fourth follow-up PET/CT scan and the scans performed after the fourth scan were included in the study.…”

“…Similar results were obtained by other studies (11,12). Although there have been many studies demonstrating the impact of 18 F-FDG PET/CT on the management plan at staging (13) and in patients with suspected disease recurrence (14,15), there is no substantial literature evaluating this clinical question in follow-up PET/CT studies. Our previous study evaluating the value of 18 F-FDG PET/CT performed 6 mo after completion of treatment demonstrated that these scans are valuable in predicting survival outcomes and add value to clinical judgment, regardless of the timing of the follow-up scan (16).…”

“…18 F-FDG PET/CT is a valuable investigation for many oncology patients for staging, therapy assessment, management, and prognosis (5-9). Toba et al (10) evaluated the role of 18 F-FDG PET/CT in postoperative follow-up of asymptomatic nonsmall cell lung cancer patients and showed that the PET/CT studies correctly identified disease in 94% of the patients with disease recurrence, yielding high diagnostic accuracy. Similar results were obtained by other studies (11,12).…”