Improving post‑CRT neck assessment in patients with HPV‑associated OPSCC (Review)

Abstract

The positive predictive value (PPV) of 12-week post-therapy FDG-PET/CT is low in patients with Human Papillomavirus (HPV)-associated Oropharyngeal Squamous Cell Carcinoma (OPSCC) after treatment with definitive chemoradiation (CRT). Moreover, the diagnostic performance of post-CRT fine needle aspiration (FNA) in detecting persistent disease is unknown in this population. Given these important shortcomings in post-CRT treatment assessment, head and neck oncologists are limited in appropriately selecting patients for consolidative neck dissection, which results in over-treatment of a favorable risk population. Using the PubMed database, we performed a literature review of published series in HPV-associated OPSCC to investigate potential strategies for improvement of post-CRT neck assessment. Several different approaches were found, including continued surveillance with PET/CT, delayed timing of restaging PET/CT, initial response evaluation with multimodality or alternative imaging, and detection of circulating HPV DNA. At present, the optimal approach to post-CRT treatment assessment is unclear; further investigation and incorporation of new technologies and surveillance protocols will be highly beneficial for patients with HPV-associated OPSCC. Contents 1. Introduction 2. Strategies to improve post-CRT neck assessment 3. Conclusions and prospects

Post‐treatment 18F‐fludeoxyglocuse‐positron emission tomography in human papillomavirus‐associated oropharyngeal cancer

“…Although some authors have suggested adoption of specific paradigms reliant on PET imaging results, there still remains a lack of consensus. 13 Many of these suggested paradigms are reliant on interpretation of imaging, without objective and standardized response criteria in the post-treatment setting. Our results support the findings of other authors who have also identified high rates of equivocal results in post-treatment PET imaging.…”

“…The surveillance and follow‐up of patients with OPSCC remains complex without adequate frameworks as to timing and duration. Although some authors have suggested adoption of specific paradigms reliant on PET imaging results, there still remains a lack of consensus 13 . Many of these suggested paradigms are reliant on interpretation of imaging, without objective and standardized response criteria in the post‐treatment setting.…”

Imaging of human papilloma virus associated oropharyngeal squamous cell carcinoma and its impact on diagnosis, prognostication, and response assessment

“…For example, there may be partial metabolic response on 18 F FDG PET-CT or there may be visible residua on CT or MRI with reduced 18 F-FDG uptake ( Figure 7 ). 160 Ultrasound-guided FNA has a role in evaluating such equivocal nodal findings; however, there are impediments to its utility due to treatment-related fibrosis and necrosis, which can make evaluation of greyscale appearances challenging and limit the yield of diagnostic material. 161 In patients treated with CRT for HNSCC, there are reports of high false positive and false negative rates for ultrasound-FNA 160,162,163 In the context of HPV+ OPC, there is a further challenge with regard to the longer time for complete regression of nodal lesions, which may be compounded by challenges interpreting the viability of irradiated cells on FNA cytology specimens, leading to reduced reliability.…”

“… 161 In patients treated with CRT for HNSCC, there are reports of high false positive and false negative rates for ultrasound-FNA 160,162,163 In the context of HPV+ OPC, there is a further challenge with regard to the longer time for complete regression of nodal lesions, which may be compounded by challenges interpreting the viability of irradiated cells on FNA cytology specimens, leading to reduced reliability. 160 Therefore, serial ultrasound demonstrating regression can be helpful in guiding management. 145 Overall, ultrasound-FNA is a useful tool for evaluating the post-treatment neck, but its limitations should be considered and results interpreted in a multidisciplinary setting and in the context of other clinicoradiological parameters.…”

Longitudinal measurement of HPV copy number in cell-free DNA is associated with patient outcomes in HPV-positive oropharyngeal cancer

“…Imaging surveillance to screen for recurrence is limited by the low positive predictive value of PET-CT [12] and can be a source of patient anxiety [13]. Post-treatment biopsy is limited due to the difficult interpretation of cell viability following chemoradiotherapy (CRT) [14,15]. Surgical intervention is associated with post-operative morbidity [16] with the potential for resecting tissue with no active disease [15,17].…”