Positive Oropharyngeal Cancer Research Articles

Hypofractionated radiation therapy alone for human papillomavirus-related oropharyngeal cancer.

To report a single-institutional experience with hypofractionated radiation therapy alone for human papillomavirus (HPV)-positive oropharyngeal cancer. A total of 101 consecutive patients were treated by radiation therapy alone using a regimen of 66 Gy in 30 fractions (60 patients) or 70 Gy in 33 fractions (41 patients) for newly diagnosed p16-positive squamous cell carcinoma of the oropharynx. Sixty-seven patients (67%) were never smokers. The 3-year actuarial rates of overall survival, local-regional control, and progression-free survival were 94%, 93%, and 89%, respectively. Among never-smokers, the 3-year rates of overall survival and local-regional control were 98% and 100%, respectively. The grade 3+ acute toxicity rate was 21%, with the most commonly observed side effects related to mucositis. Hypofractionated radiation alone resulted in excellent outcomes for patients with HPV-positive oropharyngeal cancer. A prospective clinical trial investigating this modality in the setting of de-escalation is currently underway.

Prognostic nutritional index (PNI) correlates with survival in head and neck cancer patients more precisely than other nutritional markers - real world data.

The survival benefit with higher body mass index (BMI) of patients suffering from head and neck squamous cell carcinoma (HNSCC) is documented as BMI paradox. As the early re-nourishment of high-risk patients determine survival, we searched for a nutritional status marker suitable for everyday screening. Grouping patients based on the 8th Edition of TNM Classification, we investigated for the first time the candidate nutritional status markers among TNM8 subgroups, including the newly introduced p16 positive oropharyngeal squamous cell cancer (OPSCC) patients. We conducted a retrospective cohort study enrolling 661 patients and collecting anthropometric indices, laboratory parameters, clinical scores, nutritional risk scores. To discover the best one for screening survival analyses and correlation tests were executed. By performing univariate Cox regression, we found three nutritional markers significantly correlating with overall survival (OS) and cancer specific survival (CSS): BMI at diagnosis, percent of weight loss over six months and prognostic nutritional index (PNI). The latter proved to be independent of tumor stage. p16 negative OPSCC patient's OS and CSS did not correlate with BMI, but it did correlate with PNI and percent of weight loss. BMI was the only marker correlating with OS, only in stage 4 hypopharyngeal cancer patients. All three markers significantly correlated with survival among p16 positive oropharyngeal and glottic cancer patients. We found BMI, percent of weight loss and PNI good candidate markers for malnutrition. PNI proved to be superior in every aspect, enabling the treating physicians to discover high-risk patients in need of aggressive re-nourishment. The survival of supraglottic laryngeal squamous cancer patients seemed to be independent of these nutritional status markers, which observation should be a subject of further investigations.

Evaluating the Accuracy of ChatGPT in Common Patient Questions Regarding HPV+ Oropharyngeal Carcinoma.

Large language model (LLM)-based chatbots such as ChatGPT have been publicly available and increasingly utilized by the general public since late 2022. This study sought to investigate ChatGPT responses to common patient questions regarding Human Papilloma Virus (HPV) positive oropharyngeal cancer (OPC). This was a prospective, multi-institutional study, with data collected from high volume institutions that perform >50 transoral robotic surgery cases per year. The 100 most recent discussion threads including the term "HPV" on the American Cancer Society's Cancer Survivors Network's Head and Neck Cancer public discussion board were reviewed. The 11 most common questions were serially queried to ChatGPT 3.5; answers were recorded. A survey was distributed to fellowship trained head and neck oncologic surgeons at 3 institutions to evaluate the responses. A total of 8 surgeons participated in the study. For questions regarding HPV contraction and transmission, ChatGPT answers were scored as clinically accurate and aligned with consensus in the head and neck surgical oncology community 84.4% and 90.6% of the time, respectively. For questions involving treatment of HPV+ OPC, ChatGPT was clinically accurate and aligned with consensus 87.5% and 91.7% of the time, respectively. For questions regarding the HPV vaccine, ChatGPT was clinically accurate and aligned with consensus 62.5% and 75% of the time, respectively. When asked about circulating tumor DNA testing, only 12.5% of surgeons thought responses were accurate or consistent with consensus. ChatGPT 3.5 performed poorly with questions involving evolving therapies and diagnostics-thus, caution should be used when using a platform like ChatGPT 3.5 to assess use of advanced technology. Patients should be counseled on the importance of consulting their surgeons to receive accurate and up to date recommendations, and use LLM's to augment their understanding of these important health-related topics.

Clinical prognostic factors to guide treatment strategy for HPV‑positive oropharyngeal cancer using treatment outcomes of induction chemotherapy: A real‑world experience.

The role of induction chemotherapy (IC) in locally advanced oropharyngeal cancer (OPC) remains debatable, and suitable candidates for de-escalation treatment in these patients have not been fully identified. Therefore, the present study aimed to identify high-risk candidates for human papillomavirus (HPV)-positive OPC by analyzing patients who underwent IC followed by chemoradiotherapy (CRT) to guide optimal treatment strategies. Patients diagnosed with stage III-IVA OPC and treated with a minimum of two cycles of IC followed by CRT, between 2004 and 2020, were retrospectively reviewed. All the patients were restaged according to the American Joint Committee on Cancer, 8th edition. The overall response rate and survival outcomes associated with clinical factors based on HPV status were analyzed using univariate and multivariate analyses. The present study analyzed 105 patients with a median age of 60 years (range, 40-76 years). Among 105 patients, 40 (38.1%) were HPV-negative and 65 (61.9%) HPV-positive. In all patients, survival outcomes were notably poorer in patients aged ≥60 years (P=0.006) and those who did not achieve complete response post-CRT (P<0.001), irrespective of the HPV status. The median relative dose intensity of IC was ≥80%, indicating adequate treatment, regardless of age. In contrast to patients with HPV-negative OPC, age ≥60 years (P=0.011) and T4 stage (P=0.019) emerged as substantial poor prognostic factors for survival outcomes in patients with HPV-positive OPC. Patients with HPV-positive OPC were categorized into three groups based on the number of clinical factors at diagnosis (such as age and T4 stage). The progression-free and overall survival showed significant stratification across each group as the number of high-risk factors increased despite IC and CRT. The findings indicated that patients with these high-risk factors require a cautious therapeutic strategy even when they are diagnosed with HPV-positive OPC, and the role of combined modality, including IC, will need to be investigated in a randomized trial to be routinely incorporated into clinical practice.

Translational risk-adapted approaches to de-escalated radiation for human papillomavirus-positive oropharyngeal cancer: Past, present, and future

Interest in the use of de-escalated radiation to treat patients with newly diagnosed human papillomavirus (HPV)-positive oropharyngeal cancer has grown dramatically with the publication of prospective trials demonstrating the efficacy of such an approach. While the rationale for de-escalation--- namely to decrease treatment-related toxicity while maintaining the excellent rates of disease control historically observed in patients with this disease—is inherently obvious, uncertainty exists regarding how to best select patients for de-escalation. Consequently, risk-adapted strategies using a variety of translational and clinical platforms have been increasingly popularized to better refine treatment. These have integrated contemporary methods of mid-treatment response assessment using advanced technologies and molecular assays to customize the radiation dose. By monitoring the response as patients actively proceed through treatment, risk-adapted protocols have the potential to provide insight into the biological behavior of tumors and make individualized therapy possible. The purpose of this review is to summarize the evidence to date on risk-adapted approaches to de-escalated radiation-- highlighting the clinical, radiological, and biological data which may ultimately help usher the principles of precision medicine into practice for patients with HPV-positive oropharyngeal cancer.

Sexual history of patients with human papillomavirus positive and negative oropharyngeal cancer: A systematic review and meta-analysis.

Increased sexual activity is associated with higher human papillomavirus (HPV) rates; however, there is a lack of analysis comparing the sexual history of patients with HPV positive and HPV negative oropharyngeal cancer (OPC). In this meta-analysis, PubMed, Scopus, and CINAHL were searched for articles that included patients with OPC and reported information regarding HPV status and either history of oral sex, number of sexual partners, or sexually transmitted infections (STI). A total of 11 studies were included with 3296 patients with OPC. Patients with HPV positive OPC were more likely than patients with HPV negative OPC to report a history of oral sex (92%, 95% CI: 87.0-97.0 vs. 74.5%, 95% CI: 50.6-98.4, p < 0.0001), higher mean number of sexual partners (18.4 partners, 95% CI: 1.5-35.4 vs. 7.2 partners, 95% CI: 1.0-13.4, p < 0.0001), and more frequent history of STI (23.7%, 95% CI: 18.4-29.0 vs. 8.8%, 95% CI: 4.7-12.8, p = 0.0001). Compared to patients with HPV negative OPC, our analysis shows a larger proportion of patients with HPV positive OPC had participated in oral sex, had a higher number of sexual partners, and had a higher proportion of STI history.

Population-level incidence of human papillomavirus-positive oropharyngeal, cervical, and anal cancers, by smoking status.

We estimated the population-level incidence of human papillomavirus (HPV)-positive oropharyngeal, cervical, and anal cancers by smoking status. We combined HPV DNA genotyping data from the Centers for Disease Control and Prevention's Cancer Registry Sentinel Surveillance System with data from the Kentucky Cancer Registry and Behavioral Risk Factor Surveillance System across smoking status. During 2004-2005 and 2014-2015 in Kentucky, most cases of oropharyngeal (63.3%), anal (59.7%), and cervical (54.9%) cancer were among individuals who ever smoked. The population-level incidence rate was higher among individuals who ever smoked than among those who never smoked for HPV-positive oropharyngeal (7.8 vs 2.1; adjusted incidence rate ratio = 2.6), cervical (13.7 vs 6.8; adjusted incidence rate ratio = 2.0), and anal (3.9 vs 1.6; adjusted incidence rate ratio = 2.5) cancers. These findings indicate that smoking is associated with increased risk of HPV-positive oropharyngeal, cervical, and anal cancers, and the population-level burden of these cancers is higher among individuals who ever smoked.

Involved Site Radiotherapy in HPV Positive Oropharyngeal Cancer: Patterns of Failure Analysis Across Prospective De-Escalation Trials

HPV-associated oropharyngeal cancers (HPV+OPC) have a favorable prognosis with ongoing efforts to reduce long term toxicity while maintaining oncologic outcomes. One method under investigation includes lowering the elective radiation dose or in some cases omitting radiation to elective lymphatic nodal stations. Furthermore, pre-clinical evidence demonstrates that elective nodal irradiation blunts the anti-tumor immune response in head and neck cancer. This is a pooled secondary analysis reporting patterns of failure in patients (pts) with HPV+OPC enrolled on consecutive induction chemo- or chemoimmunotherapy (IC) based response-adaptive de-escalation trials and treated with involved-site radiotherapy (ISRT). Pts treated on two prospective phase II trials as well as on a prospective cohort registry were included for analysis. Pts with ≥ 50% response to IC based on RECIST 1.1 who received de-escalated definitive radiotherapy (RT) or concurrent chemoradiation (CRT) with ISRT were evaluable. Pts with locally advanced low risk or high-risk HPV+OPC (LR and HR, respectively) were eligible for enrollment. Pts were considered to have HR if at least one of the following criteria was met: T4 primary, N2c-N3 disease (AJCC 7th ed.), or > 10-20 pack years smoking. In the first trial, pts with ≥ 50% response to IC received RT to gross disease plus a 1.5 cm margin (PTV1) and to the next echelon of uninvolved nodes (PTV2). Pts with LR received 50 Gy in 2 Gy daily fractions without chemotherapy; pts with HR received 30 Gy in 1.5 Gy BID fractions to PTV2 with a 15 Gy sequential boost to PTV1 with CRT. In the subsequent trial, pts with ≥ 50% response received RT to PTV1 alone to 50 Gy in 2 Gy daily fractions; concurrent CRT was included if pts had HR. Survival was estimated using the Kaplan Meier method for progression free survival (PFS), locoregional PFS (LRPFS), and overall survival (OS). Patterns of failure analysis was performed by comparing RT plans to radiographic surveillance scans. Of 172 evaluable pts, 119 (69.2%) achieved a ≥ 50% response to IC and received definitive ISRT. 45 (37.8%) pts evaluated received RT to gross disease only plus margin without the next nodal echelon included. With a median follow up of 46 (IQR 34-65) months, 3-year PFS, LRPFS, and OS with their 95% confidence intervals were 96.2% (90.1-98.5%), 97.1% (91.1-99.0%), and 96.2% (90.3-98.6%), respectively. All locoregional failures were in-field and in the high dose region. No failures were observed in the RT omitted neck. This prospective experience demonstrates feasible volume de-escalation using IC response-based selection with progressively smaller elective volumes over time. Notably, despite a marked reduction in elective treatment volume, there were no regional out-of-field failures. IC may allow for selection of pts with favorable tumor biology and microscopic disease sterilization in the regional nodes. Further efforts at elective nodal de-escalation are needed.

110 HPV-Positive Oropharyngeal Cancer: A Review of De-Escalation Strategies Used to Improve Outcomes for This Patient Cohort

Abstract Aim Human Papillomavirus (HPV) positive oropharyngeal cancer (OPC) has been shown to provide improved survival compared to HPV negative patients with similar disease. This has led to a new staging criteria for these patients and attempts to de-escalate treatment for this group, to maintain high survival and reduce associated side effects. This review aims to assess current research into treatment techniques and compare results of these studies. Method Pubmed online database was used to gather studies containing primary research dated from within the last 10 years detailing the study design, the striation of patients into higher and lower risk groups, and the outcome of de-escalation of treatment to these groups. Results Published studies vary in their definition of their ‘low risk’ group, however minimal smoking history, smaller tumour size and increased HPV DNA expression within the tumour are all identified as good prognostic indicators and could be and have been used to identify suitable candidates for treatment deintensification. The combination of radiotherapy and chemotherapy are often used with good success however, no consensus has been reached regarding dosing of these. Transoral robotic surgery may also be used in conjunction with chemoradiotherapy, however large ongoing studies regarding this are yet to publish their final results. Conclusions This is an evolving area of oncology with an increasing evidence base improving prognosis and minimising side effects for this group of patients, however more research is necessary to gain consensus on the gold standard treatment for these patients.

Global epidemiologic patterns of oropharyngeal cancer incidence trends.

The emergence of human papillomavirus (HPV)-positive oropharyngeal cancer and evolving tobacco use patterns have changed the landscape of head and neck cancer epidemiology internationally. We investigated updated trends in oropharyngeal cancer incidence worldwide. We analyzed cancer incidence data between 1993 and 2012 from 42 countries using the Cancer Incidence in Five Continents database volumes V through XI. Trends in oropharyngeal cancer incidence were compared with oral cavity cancers and lung squamous cell carcinomas using log-linear regression and age period-cohort modeling. In total, 156 567 oropharyngeal cancer, 146 693 oral cavity cancer, and 621 947 lung squamous cell carcinoma patients were included. Oropharyngeal cancer incidence increased (P < .05) in 19 and 23 countries in men and women, respectively. In countries with increasing male oropharyngeal cancer incidence, all but 1 had statistically significant decreases in lung squamous cell carcinoma incidence, and all but 2 had decreasing or nonsignificant net drifts for oral cavity cancer. Increased oropharyngeal cancer incidence was observed both in middle-aged (40-59 years) and older (≥60 years) male cohorts, with strong nonlinear birth cohort effects. In 20 countries where oropharyngeal cancer incidence increased for women and age period-cohort analysis was possible, 13 had negative or nonsignificant lung squamous cell carcinoma net drifts, including 4 countries with higher oropharyngeal cancer net drifts vs both lung squamous cell carcinoma and oral cavity cancer (P < .05 for all comparisons). Increasing oropharyngeal cancer incidence is seen among an expanding array of countries worldwide. In men, increased oropharyngeal cancer is extending to older age groups, likely driven by human papillomavirus-related birth cohort effects. In women, more diverse patterns were observed, suggesting a complex interplay of risks factors varying by country, including several countries where female oropharyngeal cancer increases may be driven by HPV.

Serum and Saliva Level of miR-31-5p and miR-let 7a in EBV Associated Oropharyngeal Cancer.

Epstein-Barr virus (EBV) has a well-documented association with head and neck neoplasms, including nasopharyngeal carcinoma (NPC). In the last few years, research aimed at elucidating the role of the miRs in the pathogenesis of head and neck cancer (HNC) has gained importance. The study of miRs expression has set new directions in the search for biomarkers with diagnostic and prognostic value, and even in the search for new therapeutic targets for various tumors, including HNC. The aim of current study was to approximate the importance of miR-31-5p and miR-let 7a in the pathogenesis of EBV associated oropharyngeal cancer. For this purpose, experiments were carried out to determine the level of mentioned miRs in serum among patients diagnosed with oropharyngeal cancer linked to EBV infection, depending on histological differentiation-grading (G1-G3) and TNM classification. All clinical specimens stratified by HPV status were HPV negative. The level of antibodies EBNA and EBVCA was also assessed. The obtained results showed a significantly increased serum level of miR-31-5p but decreased level of miR-let 7a in EBV positive oropharyngeal cancer patients. We demonstrated association between the level of tested miRs and clinical stage. Our findings showed that miR-31-5p and miR-let-7a may be involved in development and progression of EBV associated oropharyngeal cancer. Therefore, it seems important to further study these molecules, as well as to determine whether they could be important biomarkers in the diagnosis of oropharyngeal cancer associated with EBV infection.

A comparison of loco-regional relapse pattern in HPV positive vs negative oropharyngeal cancers following radiotherapy; relation to pretreatment FDG-PET and radiotherapy target volumes

Background Previous studies have shown that a large proportion of relapses in head-and neck squamous cell carcinoma (HNSCC) following radiotherapy (RT) occur in the pretreatment FDG-PET avid volume (GTV-PET). The aim of the current work was to see if this was valid also in an oropharynx squamous cell carcinoma (OPSCC) only population, and to compare the loco-regional relapse pattern between HPV positive and HPV negative patients. Material and methods Among 633 OPSCC patients treated between 2009 and 2017, 46 patients with known HPV (p16) status and isolated loco-regional relapse were included. Oncologists contoured relapse volumes (RV) on relapse scans (PET/CT, CT or MR), which were thereafter deformed to match the anatomy of the planning CTs. The point of origin (center of volume) of the deformed RVs were determined and analyzed in relation to the RT target volumes (GTV-PET, GTV and CTVs). The relapse pattern was compared between HPV positive and HPV negative patients using Fischer’s exact test. Results Sixty RVs were contoured in the 46 patients. 55% (95% CI 44–67%) of relapses originated in GTV-PET, while the other RT volumes harbored 12% (5–20%) (GTV), 18% (9–28%) (high risk CTV) and 5% (0–11%) (low risk CTV) of relapses. Six relapses were found outside the RT target volumes. No significant difference in relapse pattern between HPV positive and HPV negative patients was found (p = .95). Conclusion There were no signs of difference in loco-regional relapse pattern between HPV positive and HPV negative patients. In agreement with previous findings, GTV-PET was the most frequent RT target volume of relapse.

PO-1193 Pattern of practice in elderly patients with HPV positive oropharyngeal cancer: a multicenter study

PO-1193 Pattern of practice in elderly patients with HPV positive oropharyngeal cancer: a multicenter study

Upper age limits for US male human papillomavirus vaccination for oropharyngeal cancer prevention: a microsimulation-based modeling study.

Human papillomavirus (HVP)-positive oropharyngeal cancer is the most common HPV-associated cancer in the United States. The age at acquisition of oral HPV infections that cause oropharyngeal cancer (causal infections) is unknown; consequently, the benefit of vaccination of US men aged 27-45 years remains uncertain. We developed a microsimulation-based, individual-level, state-transition model of oral HPV16 and HPV16-positive oropharyngeal cancer among heterosexual US men aged 15-84 years, calibrated to population-level data. We estimated the benefit of vaccination of men aged 27-45 years for prevention of oropharyngeal cancer, accounting for direct- and indirect effects (ie, herd effects) of male and female vaccination. In the absence of vaccination, most (70%) causal oral HPV16 infections are acquired by age 26 years, and 29% are acquired between ages 27 and 45 years. Among men aged 15-45 years in 2021 (1976-2006 birth cohorts), status quo vaccination of men through age 26 years is estimated to prevent 95% of 153 450 vaccine-preventable cancers. Assuming 100% vaccination in 2021, extending the upper age limit to 30, 35, 40, or 45 years for men aged 27-45 years (1976-1994 cohorts) is estimated to yield small benefits (3.0%, 4.2%, 5.1%, and 5.6% additional cancers prevented, respectively). Importantly, status quo vaccination of men through age 26 years is predicted to result in notable declines in HPV16-positive oropharyngeal cancer incidence in young men by 2035 (51% and 24% declines at ages 40-44 years and 45-49 years, respectively) and noticeable declines (12%) overall by 2045. Most causal oral HPV16 infections in US men are acquired by age 26 years, underscoring limited benefit from vaccination of men aged 27-45 years for prevention of HPV16-positive oropharyngeal cancers.

Prognostic stratification of oropharyngeal cancer patients in a betel nut chewing and low HPV area

BackgroundThis study aimed to establish a simple predictive model for oropharyngeal cancer (OPC) in an area with a relatively low prevalence of human papillomavirus (HPV) and frequent betel nut chewing.MethodsA total of 116 patients with OPC were recruited from the clinical research database of a referral cancer center between 2013 and 2018. Patient characteristics—including age, gender, tumor stage, differentiation, and treatment modality—were extracted from the database. Patients diagnosed after 2018 were staged using the 7th AJCC staging system to explore the impact of extra-nodal tumor extension (ENE) on survival. Immunohistochemical analysis was performed for p16, epidermal growth factor receptor (EGFR), p53, and programmed cell death ligand 1 (PD-L1). ENE status was evaluated by pathological analysis or radiological features. Primary outcome was disease-specific overall survival (OS). Univariate and multivariate Cox regression were used to establish a predictive model.ResultsMean age was 57.3 ± 9.9 years; 103 patients (88.8%) were male. P16 positive OPC was positively associated with higher PD-L1 and a tonsillar sub-site and negatively associated with betel nut chewing and cigarette smoking. In Cox regression, age, p16 status, EGFR, cT4, ENE, and cigarette smoking were significantly associated with OS. In survival tree analysis, cT stage was the most important risk stratification parameter, followed by EGFR expression and p16 status. Patients with cT4 stage or high EGFR were classified as the high-risk group and had poorest OS.ConclusionsDue to the low prevalence of HPV and popularity of betel nut chewing in Asia, the relative importance of prognostic predictors for OPC are not identical to Western countries. Identification of significant prognostic biomarkers may improve treatment.Trial registration This study was registered and approved by the Institutional Review Board (IRB) of Kaohsiung Veterans General Hospital (VGHKS19-CT9-07; date of approval: Aug 9, 2019).Graphic

Oxygen-enhanced MRI and radiotherapy in patients with oropharyngeal squamous cell carcinoma

Background and purposeThis study aimed to assess the role of T1 mapping and oxygen-enhanced MRI in patients undergoing radical dose radiotherapy for HPV positive oropharyngeal cancer, which has not yet been examined in an OE-MRI study. Materials and methodsVariable Flip Angle T1 maps were acquired on a 3T MRI scanner while patients (n = 12) breathed air and/or 100 % oxygen, before and after fraction 10 of the planned 30 fractions of chemoradiotherapy (‘visit 1’ and ‘visit 2’, respectively). The analysis aimed to assess to what extent (1) native R1 relates to patient outcome; (2) OE-MRI response relates to patient outcome; (3) changes in mean R1 before and after radiotherapy related to clinical outcome in patients with oropharyngeal squamous cell carcinoma. ResultsDue to the radiotherapy being largely successful, the sample sizes of non-responder groups were small, and therefore it was not possible to properly assess the predictive nature of OE-MRI. The tumour R1 increased in some patients while decreasing in others, in a pattern that was overall consistent with the underlying OE-MRI theory and previously reported tumour OE-MRI responses. In addition, we discuss some practical challenges faced when integrating this technique into a clinical trial, with the aim that sharing this is helpful to researchers planning to use OE-MRI in future clinical studies. ConclusionAltogether, these results suggest that further clinical OE-MRI studies to assess hypoxia and radiotherapy response are worth pursuing, and that there is important work to be done to improve the robustness of the OE-MRI technique in human applications in order for it to be useful as a widespread clinical technique.

O3.1 Differences between HPV positive and HPV negative oropharyngeal cancer detected by Non-Gaussian IVIM

O3.1 Differences between HPV positive and HPV negative oropharyngeal cancer detected by Non-Gaussian IVIM

Radiation Dose and Volume De-Escalation for High-Risk HPV Positive Oropharyngeal Cancer

<h3>Purpose/Objective(s)</h3> Human papillomavirus (HPV) associated oropharyngeal cancers (HPV+OPC) have a favorable prognosis with standard of care treatment paradigms. Recently published and ongoing clinical trials are investigating therapy de-escalation for patients with HPV+OPC with low-risk features with promising results, but largely exclude high risk (HR) patients. This is a secondary pooled analysis reporting outcomes of patients with HR HPV+OPC treated on consecutive prospective response-adaptive de-escalation trials. <h3>Materials/Methods</h3> Patients meeting HR criteria treated on the prospective phase II trials (NCT02258659, NCT03107182) as well as on a prospective cohort registry were included for analysis. HR criteria were defined by the NRG-HN005 exclusion criteria (T4, N2c-N3 (AJCC 7th ed.), and/or > 10 pack year smoking history). Patients were treated with induction chemo- or chemoimmunotherapy followed by RECIST 1.1 response adapted volume and dose de-escalated definitive chemoradiation. Patients with ≥ 50% response to induction therapy were treated either to 45 Gy in 1.5 Gy BID fractions with 3 cycles of TFHX in a week on week off fashion or to 50 Gy in 2 Gy daily fractions delivered over 5 weeks with concurrent cisplatin. Those with < 50% response received standard dose chemoradiotherapy. Descriptive statistics were used to summarize patient characteristics. Survival was estimated using the Kaplan Meier method for progression free survival (PFS), locoregional PFS (LRPFS), and overall survival (OS). Log rank analysis was used to investigate association between the number of NRG risk factors (RF) (1 vs > 1 RF) and LRPFS. <h3>Results</h3> 80 patients met HR criteria and were evaluable (15 registry patients). Median follow up was 38.5 (IQR 27.25-61.25) months. 60% smoked > 10 pack years. 25% of patients had T4 and 45% had N2c-N3 disease. 72.5%, 25%, and 2.5% had 1, 2, and 3 NRG RF, respectively. 56 of 80 (70%) patients were de-escalated. 3-year PFS, OS, and LRPFS was 92.9%, 93.5%, and 94.7%, respectively. Locoregional failure (LRF) was 1.7% in patients with 1 NRG RF, and 13.6% LRF in patients with 2 or 3 NRG RF (p=0.0265). 3-year LRPFS was 100% for patients with N0-N2b disease and 88.6% for patients with N2c-N3 disease; all 4 locoregional failures were in-field and in patients with N2c-N3 disease who were de-escalated. Only 1 patient had an isolated distant failure. <h3>Conclusion</h3> This prospective experience demonstrates feasible dose and volume de-escalation of HPV+OPC patients with NRG HR factors. The results for the overall cohort compare favorably to prior published results. Importantly, the failure rate in de-escalated patients is in line with acceptability criteria on prior phase II de-escalation studies for low-risk patients. No patients experienced regional out-of-field failures and distant failure rates were low in a traditionally HR population. Our pooled results call for renewed cooperative group focus on trial design for radiation dose de-escalation for HPV+ patients with higher-risk disease features.

P16 Regulates Transcription Factor Sp1 Function to Affect Outcome in Oropharyngeal Cancer

<h3>Purpose/Objective(s)</h3> Our group has previously demonstrated that p16 activates a ubiquitin mediated pathway to repress homologous recombination via activation of HUWE1, potentially via the transcription factor Sp1. However, the specific mechanism of this interaction and its clinical significance remain to be determined. We performed <i>in vitro</i> analysis of p16 and Sp1 interaction in multiple contexts and performed correlative analysis using the head and neck TCGA clinical data, as well as analysis of HPV+ and HPV- oropharyngeal cancer (OPC) treated with chemoradiation (CRT) to evaluate the combined importance of p16 and Sp1 on outcome. We hypothesized that p16 increases the Sp1-HUWE1 interaction. <h3>Materials/Methods</h3> For clinical outcome, 100 patients with oropharyngeal cancer evenly divided between p16+ and p16- and treated with chemoradiation were evaluated for gene expression using targeted multiplex analysis platform. Additional clinical correlative analyses between HPV, p16, HUWE1 and Sp1 were performed using the TCGA Head and Neck cohort (n=530). UM-SCC-47 p16 CRISPR KO and HN5 cells harboring doxycycline-inducible p16 were used to perform <i>in vitro</i> studies. Immunoprecipitation (IP) was used to confirm the protein-protein interaction between protein p16 and transcription factor Sp1. Chromatin immunoprecipitation (ChIP) assay was used to determine the existence of the Sp1 protein-HUWE1 DNA promoter interaction. <h3>Results</h3> Sp1 (p=7.9e⁻¹⁶) and HUWE1 (p=7.9e⁻⁴) were expressed at significantly higher levels in HPV+ tumors and Sp1 and HUWE1 gene expression were highly correlated (p=5.3e10⁻⁴⁵) in the TCGA Head and Neck cohort. In addition, Sp1 expression was significantly higher in p16 positive OPC tumors in a separate patient cohort (p=3e⁻³). In OPC patents treated uniformly with CRT, the combination of p16 and Sp1 expression were associated with reduced locoregional recurrence following CRT (p=7e⁻⁶), effectively delineating good prognosis p16- patients and poor prognosis p16+ patients. IP of p16 in HN5 cells showed increased interaction with Sp1 after doxycycline-induced p16INK4a expression, and in combination with IR. ChIP assay demonstrated SP1 dependent enrichment in 2 of 5 GC box regions of the human HUWE1 promoter. More importantly, these SP1 protein-HUWE1 promoter interactions were significantly enhanced after p16 overexpression. <h3>Conclusion</h3> We show Sp1 directly interacts with HUWE1 promoter resulting in an increase of HUWE1 expression, and this interaction is mediated by p16. This increase of HUWE1 expression then leads to down-regulation of homologous recombination, sensitizing cells to DNA damage. Clinical data shows the combined expression of p16, Sp1 and HUWE1 are highly correlated and that the combination of p16 and Sp1 may be an effective biomarker in OPC.

Concurrent weekly cisplatin and simultaneous integrated boost intensity-modulated radiotherapy of locally advanced squamous cell carcinoma of the head and neck.

Radiotherapy of locally advanced head and neck cancer represents a major clinical challenge. Any treatment intensification aiming at improved treatment outcomes poten-tially results in a higher toxicity. The search for optimal treatment schedule involving conventional or altered fractionation of radiotherapy and the frequency and dose of concomitant cisplatin or other systemic agents has been spanning over several decades. To evaluate long-term outcomes and toxicity of accelerated chemoradiotherapy of locally advanced squamous cell carcinoma of the head and neck (LA SCCHN). Forty patients with stage III and IVA (TNM, 7th Ed.) LA SCCHN were treated with accelerated radiotherapy with a total dose of 67.5 Gy in 6 weeks delivered with simultaneous integrated boost intensity-modulated radiotherapy (SIB IMRT) and concomitant weekly cisplatin 40mg/m2. Five-year outcomes and early and late toxicity were evaluated. With the median follow-up of 47.8 months, a 5-year locoregional control rate (LCR) was 56.5%, distant control rate (DCR) was 87% and 5-year progression-free survival (PFS) and overall survival (OS) were 37 and 45%, respectively. Cisplatin cumulative dose of 200mg/m2 was administered in 83% of patients. Grade 2 late toxicity with dietary change was observed in 21 (53%) patients. Human papillomavirus (HPV) status determined by p16 immunohistochemistry was the only significant factor in 5-year treatment outcomes analysis with LCR 100 vs. 41% (P &lt; 0.01), DCR 100 vs. 78% (P = 0.154), PFS 80 vs. 23% (P = 0.01) and OS 80 vs. 34% (P = 0.03) for HPV positive oropharyngeal cancer (OPC) and other HPV negative LA SCCHN. High proportion of patients with LA SCCHN received an adequate cumulative dose of concurrent cisplatin with accelerated radiotherapy with SIB IMRT. This study demonstrated that chemoradiotherapy with weekly cisplatin resulted in favorable local control rate and survival in patients with HPV+ OPC.