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BACKGROUND AND PURPOSE:Patients with human papillomavirus-positive oropharyngeal squamous cell carcinomas have a better survival rate than those with human papillomavirus-negative oropharyngeal squamous cell carcinomas. DWI characterizes biologically relevant tumor features, and the generated ADC may also provide prognostic information. We explored whether human papillomavirus status and ADC values are independent tumor characteristics.

The (18) F-FDG-PET-CT parameters are lower in HPV-positive than in HPV-negative patients. Low pretreatment SUV values in HPV-positive oropharyngeal SCC may be at least partly explained by HPV-induced tumor changes.

Following failure of chemoradiotherapy (CRT) for advanced staged oropharyngeal squamous cell carcinomas (OPSCC), residual tumor can often be treated successfully with salvage surgery, if detected early. Current clinical practice in the VU University Medical Center is to perform routine response evaluation, i.e., examination under general anesthesia (EUA), 12 weeks after treatment. However, in the Netherlands there is no consensus on response evaluation in patients with advanced oropharyngeal cancer. Questionnaire on current clinical practice concerning response evaluation after CRT for advanced OPSCC in all eight head and neck cancer centers of the Dutch Head and Neck Oncology Cooperative Group. The response rate was 100%. Response evaluation was routinely performed with various methods in five institutions (62.5%) and in one institute (12.5%) only if clinical evaluation was difficult. Two centers (25%) did not perform response evaluation. In case of suspicion of residual disease during follow-up, six centers (75%) performed imaging prior to EUA and two centers (25%) only if clinical evaluation was difficult. Diagnostic techniques used prior to EUA were MRI (87.5%), diffusion-weighted MRI (37.5%), 18F-FDG-PET-CT (75-87.5%) and CT (37.5%). This survey shows a substantial variation in the diagnostic policy concerning response evaluation after CRT for advanced OPSCC in the Netherlands. There is a need for guidelines for response evaluation in patients with advanced oropharyngeal cancer.

BackgroundConsiderable variation exists in diagnostic tests used for local response evaluation after chemoradiation in patients with advanced oropharyngeal cancer. The yield of invasive examination under general anesthesia (EUA) with biopsies in all patients is low and it may induce substantial morbidity. We explored four response evaluation strategies to detect local residual disease in terms of diagnostic accuracy and cost-effectiveness.MethodsWe built a decision-analytic model using trial data of forty-six patients and scientific literature. We estimated for four strategies the proportion of correct diagnoses, costs concerning diagnostic instruments and the proportion of unnecessary EUA indications. Besides a reference strategy, i.e. EUA for all patients, we considered three imaging strategies consisting of 18FDG-PET-CT, diffusion-weighted MRI (DW-MRI), or both 18FDG-PET-CT and DW-MRI followed by EUA after a positive test. The impact of uncertainty was assessed in sensitivity analyses.ResultsThe EUA strategy led to 96% correct diagnoses. Expected costs were €468 per patient whereas 89% of EUA indications were unnecessary. The DW-MRI strategy was the least costly strategy, but also led to the lowest proportion of correct diagnoses, i.e. 93%. The PET-CT strategy and combined imaging strategy were dominated by the EUA strategy due to respectively a smaller or equal proportion of correct diagnoses, at higher costs. However, the combination of PET-CT and DW-MRI had the highest sensitivity. All imaging strategies considerably reduced (unnecessary) EUA indications and its associated burden compared to the EUA strategy.ConclusionsBecause the combined PET-CT and DW-MRI strategy costs only an additional €927 per patient, it is preferred over immediate EUA since it reaches the same diagnostic accuracy in detecting local residual disease while leading to substantially less unnecessary EUA indications. However, if healthcare resources are limited, DW-MRI is the strategy of choice because of lower costs while still providing a large reduction in unnecessary EUA indications.