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Purpose: Patients with p16/human papilloma virus (HPV)-associated oropharyngeal squamous cell carcinoma have a favorable outcome after treatment. In this group of patients who could have a long life expectancy, the optimal surveillance strategy and modality is not well established. We aim to determine the ability of a negative postradiation positron emission tomography (PET)/computed tomography scan to predict the risk of subsequent relapse in these patients.Materials and Methods: A retrospective analysis of patients with p16/HPV-associated oropharyngeal squamous cell carcinoma who completed definitive (chemo)radiation therapy and had a posttreatment PET/computed tomography scan from 2006 to 2013 was performed. Patient, tumor, and treatment characteristics and clinical outcomes were recorded. Tumors were considered HPV/p16 positive if either HPV (by in situ hybridization) or p16 (by immunohistochemistry) was positive. Disease-free survival and overall survival rates were estimated using the Kaplan-Meier method.Results: In our study, 327 patients were evaluated. The median age was 57 years. The most common primary sites were base of tongue (50%) and tonsil (48%). Of the patients evaluated, 291 (89%) had a negative posttreatment PET scan. For these 291 patients who had a complete metabolic response after treatment, the 5-year disease-free survival and overall survival rates were 91% and 89%, respectively. The median time to development of recurrence was 16 months. Of the 291 patients, 24 patients (8%) had disease recurrence; 13 recurrences were locoregional, and 13 were distant. Eleven (4%) patients with recurrence had further surgery or radiation, and 8 patients (3%) were without disease as of the last follow-up.Conclusions: Patients who achieve a complete metabolic response on posttreatment PET imaging have an excellent prognosis, and the risk of developing a recurrence in the future is very low. Therefore, a more cost effective surveillance program should be considered for this subgroup of patients. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether a response assessment using mid-treatment computed tomography (CT) scans during definitive radiation therapy (RT) for oropharyngeal head and neck cancer can predict for locoregional recurrence (LRR).Methods and Materials: Head and neck cancer patients who receive RT at our institution undergo CT repeat scans at the 15th fraction, with treatment replanning in the case of an inadequate dose to gross disease or an increased dose to organs at risk. A retrospective cohort analysis was performed of 96 consecutive patients with oropharyngeal cancer treated from 2007 to 2015 with mid-treatment repeat CT scans available. The primary disease volume and involved lymph node volume were delineated on the pre- and mid-treatment CT scans. Univariable and multivariable Cox proportional hazards regression analyses were used to evaluate the efficacy of the mid-treatment reduction in tumor volume as a predictor of LRR. Risk stratification was performed by dichotomizing the patients into high- and low-risk groups according to the mid-treatment response and p16 status and smoking history.Results: With a median follow-up of 34 months, 14 patients experienced LRR. The median reduction in the total tumor volume was 18.7% (interquartile range 8.4%-30.9%). A reduction in total tumor volume greater than the median was an independent predictor of LRR (hazard ratio 0.22, 95% confidence interval 0.05-0.89; P = .020). The reduction in primary tumor volume was an even stronger predictor of LRR (hazard ratio 0.11, 95% confidence interval 0.02-0.57; P = .002). Stratifying patients into a high-risk group for those with a reduction in the total tumor volume at mid-treatment at or less than the median, p16 negative status, and smoking status of >10 pack-years and a low-risk group for those without these factors, we found a clear separation in Kaplan-Meier curves, with actuarial 3-year locoregional control, progression-free survival, and overall survival rates for the high-risk patients of 45.7%, 38.2%, and 71.8% compared with 90.7%, 70.6%, and 89.8% for low-risk patients, respectively (P ≤ .021 for all).Conclusions: Our results have shown that the treatment response from an early assessment using mid-treatment CT scans is an independent predictor of LRR and can be used to effectively distinguish high- and low-risk patients, allowing for risk-adaptive treatment stratification at the midway point. [ABSTRACT FROM AUTHOR]

Purpose Distant metastasis (DM) is the main cause of death for patients with human papillomavirus (HPV)–related oropharyngeal cancers (OPCs); yet, there are few reliable predictors of DM in this disease. The role of quantitative imaging (ie, radiomic) analysis was examined to determine whether there are primary tumor features discernible on imaging studies that are associated with a higher risk of DM developing. Methods and Materials Radiation therapy planning computed tomography scans were retrieved for all nonmetastatic p16-positive OPC patients treated with radiation therapy or chemoradiation therapy at a single institution between 2005 and 2010. Radiomic biomarkers were derived from each gross tumor volume. The biomarkers included 4 representative radiomic features from tumor first-order statistics, shape, texture, and wavelet groups, as well as a combined 4-feature signature. Univariable Cox proportional hazards models for DM risk were identified. The discriminative performance of prognostic univariable and multivariable models was compared using the concordance index (C-index). Subgroup analyses were performed. Results There were 300 HPV-related OPC patients who were eligible for the analysis. A total of 36 DM events occurred within a median follow-up period of 5 years. On univariable analysis, top results included the 4 representative radiomic features (C-index, 0.670-0.686; P <.001), the radiomic signature (C-index, 0.670; P <.001), tumor stage (C-index, 0.633; P <.001), tumor diameter (C-index, 0.653; P <.001), and tumor volume (C-index, 0.674; P <.001), which demonstrated moderate discrimination of DM risk. Combined clinical-radiomic models yielded significantly improved performance (C-index, 0.701-0.714; P <.05). In subgroup analyses, the radiomic biomarkers consistently stratified patients for DM risk, particularly for those cohorts with greater risks (C-index, 0.663-0.796), such as patients with stage III disease. Conclusions Radiomic biomarkers appear to classify DM risk for patients with nonmetastatic HPV-related OPC. Radiomic biomarkers could be used either alone or with other clinical characteristics in the assignment of DM risk in future HPV-related OPC clinical trials. [ABSTRACT FROM AUTHOR]