Mesothelioma: Pleural, Version 1.2024.

Mesothelioma is a rare cancer that originates from the mesothelial surfaces of the pleura and other sites, and is estimated to occur in approximately 3,500 people in the United States annually. Pleural mesothelioma is the most common type and represents approximately 85% of these cases. The NCCN Guidelines for Mesothelioma: Pleural provide recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with pleural mesothelioma. These NCCN Guidelines Insights highlight significant updates to the NCCN Guidelines for Mesothelioma: Pleural, including revised guidance on disease classification and systemic therapy options.

Hematology and Oncology Fellow Education About Sexual and Reproductive Health: A Survey of Program Directors in the United States.

PURPOSE: Clinical oncology guidelines recommend addressing sexual and reproductive health (SRH) concerns in routine cancer care. However, limited training often hinders clinicians' ability to do so effectively. The objective of this study was to understand the state of current fellowship education on SRH (ie, sexual health, safe sex practices, and fertility) through conducting a national survey of US hematology/oncology fellowship program directors (PDs). METHODS: A survey was sent to all PDs of adult hematology/oncology fellowship programs in the United States via online link. PDs who did not complete the survey were sent up to four follow-up emails and a paper mailing. Descriptive statistics and McNemar tests were conducted. RESULTS: One hundred-fourteen PDs responded (65%). Fewer programs offered formal instruction on sexual health (49%) and safe sex practices (37%) compared with fertility (75%). Informal training in SRH relied heavily on direct clinical experience (73%-78% of programs), with other methods (eg, case-based approaches, webinars, and journal clubs) being less common. Lack of experts to provide instruction was the most commonly cited barrier to offering training in SRH, endorsed by 74% for sexual health, 68% for safe sex practices, and 54% for fertility; difficulty finding space within the curriculum (50%; 54%; and 43%, respectively) and a lack of training requirements were also commonly endorsed (57%; 60%; and 35%, respectively). Barriers were endorsed more commonly for sexual health topics than fertility. CONCLUSION: The results highlight the scarcity of training in SRH, particularly in sexual health, within hematology/oncology fellowship programs. The heavy reliance on informal instruction methods may lead to inconsistent and inadequate education. Efforts to integrate comprehensive training in SRH into fellowship programs are crucial to ensuring that such concerns are included in routine cancer care.

Mesothelioma: Peritoneal, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology.

Mesothelioma is a rare cancer originating in mesothelial surfaces of the peritoneum, pleura, and other sites. These NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) focus on peritoneal mesothelioma (PeM). The NCCN Guidelines for PeM provide recommendations for workup, diagnosis, and treatment of primary as well as previously treated PeM. The diagnosis of PeM may be delayed because PeM mimics other diseases and conditions and because the disease is so rare. The pathology section was recently updated to include new information about markers used to identify mesothelioma, which is difficult to diagnose. The term "malignant" is no longer used to classify mesotheliomas, because all mesotheliomas are now defined as malignant.

A phase 2 study of neoadjuvant chemotherapy plus durvalumab in resectable locally advanced head and neck squamous cell carcinoma.

BACKGROUND: Patients with locally advanced head and neck squamous cell cancer (HNSCC) are treated with surgery followed by adjuvant (chemo) radiotherapy or definitive chemoradiation, but recurrence rates are high. Immune checkpoint blockade improves survival in patients with recurrent/metastatic HNSCC; however, the role of chemo-immunotherapy in the curative setting is not established. METHODS: This phase 2, single-arm, multicenter study evaluated neoadjuvant chemo-immunotherapy with carboplatin, nab-paclitaxel, and durvalumab in patients with resectable locally advanced HNSCC. The primary end point was a hypothesized pathologic complete response rate of 50%. After chemo-immunotherapy and surgical resection, patients received study-defined, pathologic risk adapted adjuvant therapy consisting of either durvalumab alone (low risk), involved field radiation plus weekly cisplatin and durvalumab (intermediate risk), or standard chemoradiation plus durvalumab (high risk). RESULTS: Between December 2017 and November 2021, 39 subjects were enrolled at three centers. Oral cavity was the most common primary site (69%). A total of 35 of 39 subjects underwent planned surgical resection; one subject had a delay in surgery due to treatment-related toxicity. The most common treatment-related adverse events were cytopenias, fatigue, and nausea. Post treatment imaging demonstrated an objective response rate of 57%. Pathologic complete response and major pathologic response were achieved in 29% and 49% of subjects who underwent planned surgery, respectively. The 1-year progression-free survival was 83.8% (95% confidence interval, 67.4%-92.4%). CONCLUSIONS: Neoadjuvant carboplatin, nab-paclitaxel, and durvalumab before surgical resection of HNSCC were safe and feasible. Although the primary end point was not met, encouraging rates of pathologic complete response and clinical to pathologic downstaging were observed.

Hematology/Oncology Fellows' Training in Palliative Care: A Narrative Review.

Palliative care (PC) education is a vital and required part of hematology-oncology fellows' education to build PC skills, attitudes, and knowledge. However, previous research has shown that education in PC is inadequate. This narrative review of the literature on primary PC education during hematology-oncology fellowship programs aims at identifying the current state of PC education, existing gaps, and potential future directions for improving PC education. Fourteen articles were identified and reviewed. The types of articles included trainee and program leadership responses, and interventions designed to improve PC education. Results from each study are reported. Overall, trainees and program leadership rate current PC education as varied, often inadequate, and in need of improvement. Educational interventions show that some form of PC education increases perceived knowledge and confidence in PC skills. Future studies are needed to develop the most effective and impactful educational models.

NCCN Guidelines® Insights: Non-Small Cell Lung Cancer, Version 2.2023.

The NCCN Guidelines for Non-Small Cell Lung Cancer (NSCLC) provide recommendations for management of disease in patients with NSCLC. These NCCN Guidelines Insights focus on neoadjuvant and adjuvant (also known as perioperative) systemic therapy options for eligible patients with resectable NSCLC.

Randomized Phase II Trial of Ficlatuzumab With or Without Cetuximab in Pan-Refractory, Recurrent/Metastatic Head and Neck Cancer.

PURPOSE: Primary or acquired resistance to cetuximab, an antiepidermal growth factor receptor monoclonal antibody (mAb), minimizes its utility in recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). Aberrant hepatocyte growth factor/cMet pathway activation is an established resistance mechanism. Dual pathway targeting may overcome resistance. PATIENTS AND METHODS: This multicenter, randomized, noncomparative phase II study evaluated ficlatuzumab, an antihepatocyte growth factor mAb, with or without cetuximab in recurrent/metastatic HNSCC. The primary end point was median progression-free survival (PFS); an arm met significance criteria if the lower bound of the 90% CI excluded the historical control of 2 months. Key eligibility criteria were HNSCC with known human papillomavirus (HPV) status, cetuximab resistance (progression within 6 months of exposure in the definitive or recurrent/metastatic setting), and resistance to platinum and anti-PD-1 mAb. Secondary end points included objective response rate (ORR), toxicity, and the association of HPV status and cMet overexpression with efficacy. Continuous Bayesian futility monitoring was used. RESULTS: From 2018 to 2020, 60 patients were randomly assigned and 58 were treated. Twenty-seven versus 33 patients were allocated to monotherapy versus combination. Arms were balanced for major prognostic factors. The monotherapy arm closed early for futility. The combination arm met prespecified significance criteria with a median PFS of 3.7 months (lower bound 90% CI, 2.3 months; P = .04); the ORR was 6 of 32 (19%), including two complete and four partial responses. Exploratory analyses were limited to the combination arm: the median PFS was 2.3 versus 4.1 months (P = .03) and the ORR was 0 of 16 (0%) versus 6 of 16 (38%; P = .02) in the HPV-positive versus HPV-negative subgroups, respectively. cMet overexpression was associated with reduced hazard of progression in HPV-negative but not HPV-positive disease (P interaction = .02). CONCLUSION: The ficlatuzumab-cetuximab arm met significance criteria for PFS and warrants phase III development. HPV-negative HNSCC merits consideration as a selection criterion.

Real-world progression-free survival (rwPFS) and the impact of PD-L1 and smoking in driver-mutated non-small cell lung cancer (NSCLC) treated with immunotherapy.

PURPOSE: Prior data suggest driver-mutated NSCLC, especially EGFR and ALK tumors, poorly respond to immunotherapy. However, little research using real-world cohorts have been performed, nor is it clear whether PD-L1 and smoking history are predictive of outcomes in such tumors. This study assessed rwPFS in a large cohort with driver-mutated advanced NSCLC treated with single-agent PD-1/PDL-1 inhibitors. METHODS: Real-world data from 1746 patients were analyzed and rwPFS with immunotherapy was determined for EGFR, ALK, BRAF, and KRAS tumors. Kaplan-Meier curves characterized rwPFS and correlated with PD-L1 and smoking history. Comparisons were tested using log-rank. RESULTS: Median rwPFS and the percent progression-free at 12 months were greater among KRAS (3.3 months, 21.1%) and BRAF (3.6 months, 20.6%) as compared to EGFR (2.5 months, 8.1%) and ALK tumors (2.3 months, 11.2%). KRAS tumors with PD-L1 ≥ 1% had longer rwPFS than PD-L1 < 1% tumors (4.1 versus 3.2 months, p = 0.001). PD-L1 positivity did not predict rwPFS in EGFR, ALK, or BRAF tumors. However, a smoking history was associated with longer rwPFS in EGFR (2.6 versus 2.3 months, p = 0.048) and ALK tumors (3.0 versus 2.1 months, p = 0.049) as compared to no smoking history. CONCLUSION: Real-world PFS with immunotherapy was greater in KRAS and BRAF as compared to EGFR and ALK tumors. PD-L1 positivity was predictive in KRAS and not associated with rwPFS in other mutation types. While median rwPFS was short for EGFR and ALK tumors, small subsets were progression-free at 12 months. Better characterizing these subsets that benefit, along with developing strategies to overcome immunotherapy resistance in EGFR/ALK tumors are needed.

Pembrolizumab as monotherapy in locally advanced cutaneous squamous cell carcinoma.

INTRODUCTION: Outcomes for patients with advanced cutaneous squamous cell carcinoma (cSCC) are poor, however recent approvals in programmed death-1 (PD-1) checkpoint inhibition have shown promise. Prior systemic treatments in this patient population included chemotherapy and anti-EGFR directed therapies, with limited long-term benefit. Studies investigating cemiplimab and pembrolizumab have recently revealed significant responses with many cases of sustained benefit in both locally advanced and recurrent and/or metastatic disease. While these treatments have shown improvement in outcomes, there are continued areas of need. AREAS COVERED: This review focuses on clinical evidence for PD-1 directed checkpoint inhibition in advanced cSCC. Excluded populations and new approaches involving immunotherapy are discussed. EXPERT OPINION: Immune checkpoint inhibition in advanced cSCC has shown impressive benefit. The clinical trials for both cemiplimab and pembrolizumab demonstrate similar responses and outcomes. Biomarkers for predicting response are an area of need. In addition, these trials excluded immunosuppressed patients due to hematological malignancies or prior organ transplant, which are populations with significantly increased risk of cSCC. Finally, a variety of novel approaches using checkpoint inhibition in cSCC are being investigated, with some encouraging preliminary results.

Assessing plasma circulating tumor human papillomavirus (HPV) DNA in determining treatment response in HPV-associated oropharyngeal cancer.

BACKGROUND: Human papillomavirus (HPV)-mediated oropharyngeal squamous cell carcinoma is a subset of head and neck cancer with a unique mechanism of carcinogenesis. Local disease is treated definitively with a multimodal approach. Navigating recurrences can be challenging, as they are sometimes indiscernible from de novo primary malignancies. Identification of dynamic biomarkers that are specific to HPV-mediated disease may assist in disease monitoring. We present a 78-year-old man who developed a squamous cell carcinoma in the lung 7 years after completing definitive chemoradiation for his p16+ head and neck squamous cell carcinoma. METHODS: A novel assay for plasma circulating tumor HPV DNA was employed and provided a tool for longitudinal disease monitoring during therapy. CONCLUSION: We bring attention to a novel assay and highlight its potential for use in the treatment paradigm of HPV-mediated oropharyngeal carcinoma.

Non-Small Cell Lung Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) provide recommended management for patients with NSCLC, including diagnosis, primary treatment, surveillance for relapse, and subsequent treatment. Patients with metastatic lung cancer who are eligible for targeted therapies or immunotherapies are now surviving longer. This selection from the NCCN Guidelines for NSCLC focuses on targeted therapies for patients with metastatic NSCLC and actionable mutations.

Health-Related Quality of Life of Patients with Recurrent or Metastatic Cutaneous Squamous Cell Carcinoma Treated with Pembrolizumab in KEYNOTE-629.

INTRODUCTION: Pembrolizumab provided durable responses and acceptable safety in recurrent or metastatic (R/M) cutaneous squamous cell carcinoma (cSCC) in the KEYNOTE-629 study. In this elderly, fragile population with disfiguring tumours, preservation of health-related quality of life (HRQoL) is critical. Here, we present pre-specified exploratory HRQoL analyses from the first interim analysis of KEYNOTE-629. METHODS: Patients with R/M cSCC not amenable to surgery or radiation therapy received pembrolizumab 200 mg every 3 weeks for ≤ 24 months. HRQoL end points included change from baseline to week 12 in European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) global health status (GHS)/QoL, functioning, symptom and European Quality of Life 5-Dimension 5-Level (EQ-5D-5L) scores and change from baseline through week 48 in EORTC QLQ-C30 GHS/QoL and physical functioning scores. Improvement (≥ 10-point increase post-baseline with confirmation) was assessed using the exact binomial method. RESULTS: Analyses included 99 patients for EORTC QLQ-C30 and 100 for EQ-5D-5L. Compliance was > 80% at week 12. Mean scores were stable from baseline to week 12 for GHS/QoL (4.95 points; 95% confidence interval, -1.00 to 10.90) and physical functioning (-3.38 points; 95% confidence interval, -8.80 to 2.04). EORTC-QLQ-C30 functioning, symptom, and EQ-5D-5L scores remained stable at week 12. Post-baseline scores were improved in 29.3% of patients for GHS/QoL, 17.2% for physical functioning, and in a numerically higher proportion of responders versus non-responders (GHS/QoL, 55.6% versus 16.1%; physical functioning, 36.1% versus 7.1%). CONCLUSIONS: In elderly patients with R/M cSCC, the clinical efficacy of pembrolizumab translates into a benefit validated by HRQoL preservation or improvement during treatment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03284424.

Cutaneous squamous cell carcinoma (cSCC) is the second most common type of non-melanoma skin cancer. cSCC is usually caused by cumulative exposure to sunlight and often occurs in exposed parts of the body such as the head and neck. cSCC is most often seen in older people. If cSCC is detected early, it can be removed by surgery; however, if left untreated, the cancer can spread throughout the body and cause death. The disease itself and its treatment can be painful, cause scarring, or change the patient's physical appearance. Hence, people with cSCC often have poor quality of life. It is therefore important to develop new drugs to help patients with cSCC live longer without worsening their quality of life. The phase 2 KEYNOTE-629 study investigated how well the drug pembrolizumab treated cSCC and whether it was safe. KEYNOTE-629 included patients who were mostly older and had advanced cSCC. The results showed that pembrolizumab was effective and safe. Here, we investigated how pembrolizumab affected the quality of life of these patients. To do this, we asked patients to answer questionnaires on important aspects of their experience, such as their general health status, physical functioning, emotional wellbeing, and symptoms. We found that patients who were treated with pembrolizumab had stable quality of life during treatment. Furthermore, patients whose cancer responded well to pembrolizumab were more likely to have an improved quality of life. These results support the use of pembrolizumab in patients with advanced cSCC.

NCCN Guidelines® Insights: Palliative Care, Version 2.2021.

Palliative care has evolved to be an integral part of comprehensive cancer care with the goal of early intervention to improve quality of life and patient outcomes. The NCCN Guidelines for Palliative Care provide recommendations to help the primary oncology team promote the best quality of life possible throughout the illness trajectory for each patient with cancer. The NCCN Palliative Care Panel meets annually to evaluate and update recommendations based on panel members' clinical expertise and emerging scientific data. These NCCN Guidelines Insights summarize the panel's recent discussions and highlights updates on the importance of fostering adaptive coping strategies for patients and families, and on the role of pharmacologic and nonpharmacologic interventions to optimize symptom management.

A Pilot Study of a Collaborative Palliative and Oncology Care Intervention for Patients with Head and Neck Cancer.

Background: Palliative care improves symptoms and coping in patients with advanced cancers, but has not been evaluated for patients with curable solid malignancies. Because of the tremendous symptom burden and high rates of psychological distress in head and neck cancer (HNC), we evaluated feasibility and acceptability of a palliative care intervention in patients with HNC receiving curative-intent chemoradiation therapy (CRT). Methods: This was a prospective single-arm study in HNC patients receiving CRT at a single center in the United States. The intervention entailed weekly palliative care visits integrated with oncology care with a focus on symptoms and coping. The primary outcome was feasibility, defined as a >50% enrollment rate with >70% of patients attending at least half of the visits. To assess acceptability, we collected satisfaction ratings post-intervention. We also explored symptom burden, mood, and quality of life (QOL). Results: We enrolled 91% (20/22) of eligible patients. Patients attended 133 of 138 palliative care visits (96%); all 20 attended >85% of visits. Eighteen of 19 (95%) found the intervention "very helpful" and would "definitely recommend" it. QOL and symptom burden worsened from baseline to week 5, but subsequently improved at one-month post-CRT. Overall, patients valued the one-on-one format of the intervention and receipt of additional care. Conclusions: Our palliative care intervention during highly morbid CRT was feasible and acceptable with high enrollment, excellent intervention compliance, and high patient satisfaction. Future randomized studies will further explore the impact on patient-reported outcomes and health care utilization.

NCCN Guidelines Insights: Non-Small Cell Lung Cancer, Version 2.2021.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) address all aspects of management for NSCLC. These NCCN Guidelines Insights focus on recent updates to the NCCN Guidelines regarding targeted therapies, immunotherapies, and their respective biomarkers.

Rapid recurrence in head and neck cancer: Underappreciated problem with poor outcome.

BACKGROUND: Rapid recurrence, defined as gross tumor recurrence after primary operation but prior to initiating postoperative radiation therapy (PORT), is underappreciated in head and neck cancer (HNC). METHODS: CT simulation images in patients with HNC managed surgically with adjuvant therapy at a single center between 2010 and 2017 were retrospectively reviewed. RESULTS: A total of 194 patients with HNC were included. Rapid recurrence occurred in 39 patients (20%) with a median time from operation to CT simulation of 37 days. On multivariable analysis (MVA), extranodal extension (ENE) was the only predictor of rapid recurrence (P = .03). While rapid recurrence, ENE, and perineural invasion were all associated with poor overall survival (OS) on MVA, rapid recurrence was the strongest predictor (hazard ratio [HR] 5.47). CONCLUSION: Rapid recurrence occurs at an underappreciated rate and is associated with poor survival outcomes. Patients with ENE are at highest risk and may benefit from diagnostic imaging evaluations immediately prior to PORT.

Patterns of Multidisciplinary Care of Head and Neck Squamous Cell Carcinoma in Medicare Patients.

Importance: Multidisciplinary care (MDC) yields proven benefits for patients with cancer, although it may be underused in the complex management of head and neck squamous cell carcinoma (HNSCC). Objective: To characterize the patterns of MDC in the treatment of HNSCC among elderly patients in the US. Design, Setting, and Participants: This nationwide, population-based, retrospective cohort study used Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data from January 1, 1991, to December 31, 2011, to identify patients 66 years or older diagnosed with head and neck cancer and determine the dates of diagnosis, oncology consultations, treatment initiation, and speech therapy evaluation in addition to MDC completion. Multidisciplinary care was defined in a stage-dependent manner: localized disease necessitated consultations with radiation and surgical oncologists, and advanced-stage disease also included a medical oncology consultation, all before definitive treatment. Data were analyzed between December 2016 and September 2020. Main Outcomes and Measures: Rates of MDC across all subsites of head and neck cancer as measured by the presence of an evaluation for each oncologist on the MDC team and its effect on treatment initiation. Results: This cohort study assessed 28 293 patients with HNSCC (mean [SD] age, 75.1 [6.6] years; 67% male; 87% White) from the SEER-Medicare linked database. The HNSCC subsites included larynx (40%), oral cavity (30%), oropharynx (21%), hypopharynx (7%), and nasopharynx (2%). Overall, the practice of MDC significantly increased over time, from 24% in 1991 to 52% in 2011 (P < .001). For patients with localized (stage 0-II) tumors, 60% received care in the multidisciplinary setting, whereas 28% of those with advanced-stage disease did. A total of 18 181 patients (64%) were treated with initial definitive nonsurgical therapy across all stages. Regardless of stage and subsite, few patients (2%) underwent evaluation by a speech-language pathologist before definitive therapy. Multidisciplinary care prolonged the time to initiation of definitive treatment by 11 days for localized disease and 10 days for advanced disease. Conclusions and Relevance: This cohort study found that most elderly patients with localized HNSCC received MDC, whereas few patients with advanced-stage disease received such care, although a significant proportion received adjuvant therapy. Multidisciplinary care may prolong time to initiation of definitive treatment with an uncertain impact. Consultation with a speech-language pathologist before definitive therapy was rare.

Pembrolizumab Monotherapy for Recurrent or Metastatic Cutaneous Squamous Cell Carcinoma: A Single-Arm Phase II Trial (KEYNOTE-629).

PURPOSE: Treatment options are limited for patients with recurrent and/or metastatic (R/M) cutaneous squamous cell carcinoma (cSCC); mortality rates exceed 70% in patients with distant metastases. Here, we present the first interim analysis of the R/M cSCC cohort from the 2-cohort-locally advanced and R/M-phase II KEYNOTE-629 study. PATIENTS AND METHODS: Patients with R/M cSCC not amenable to surgery or radiation received pembrolizumab 200 mg every 3 weeks. The primary end point was objective response rate per RECIST v1.1. Secondary end points were duration of response, disease control rate, progression-free survival, overall survival, and safety. RESULTS: At data cutoff (April 8, 2019), median follow-up of 105 enrolled patients in the R/M cohort was 11.4 months (range, 0.4 to 16.3 months). Objective response rate was 34.3% (95% CI, 25.3% to 44.2%; 4 complete responses, 32 partial responses), and disease control rate was 52.4% (95% CI, 42.4% to 62.2%). Median duration of response was not reached (range, 2.7 to 13.1+ months; '+' refers to ongoing response at data cutoff). Median progression-free survival was 6.9 months (95% CI, 3.1 months to 8.5 months). Median overall survival was not reached (95% CI, 10.7 months to not reached). Treatment-related adverse events occurred in 66.7% of patients (n = 70), the most common of which were pruritus (n = 15; 14.3%), asthenia (n = 14; 13.3%), and fatigue (n = 13; 12.4%). Grade 3 to 5 treatment-related adverse events occurred in 5.7% (n = 6) of patients. One patient died of treatment-related cranial nerve neuropathy. CONCLUSION: Pembrolizumab demonstrated effective antitumor activity; clinically meaningful, durable responses; and acceptable safety in primarily elderly patients with R/M cSCC, supporting its use in clinical practice. Pembrolizumab adverse events in this study were consistent with its established safety profile.

Concurrent Definitive Immunoradiotherapy for Patients with Stage III-IV Head and Neck Cancer and Cisplatin Contraindication.

PURPOSE: Although cisplatin plus radiotherapy is a standard treatment of locally advanced head and neck squamous cell carcinoma (LA-HNSCC), cisplatin contraindication is common. Radiation elicits and promotes tumor-directed immune stimulation, which may potentiate anti-PD-1 therapy. We provide the first efficacy report of combined pembrolizumab and definitive radiotherapy in LA-HNSCC. PATIENTS AND METHODS: This single-arm, multi-institution, phase II study (NCT02609503) enrolled 29 cisplatin-ineligible patients. Patients received radiotherapy concurrently with three cycles of pembrolizumab 200 mg every 3 weeks followed by three adjuvant cycles. The primary endpoint was a progression-free survival (PFS) of ≥16 months. Correlative studies included peripheral blood flow cytometry and Luminex cytokine profiling. RESULTS: Reasons for cisplatin ineligibility included otopathy (69.0%), nephropathy (20.7%), and neuropathy (6.9%). With median follow-up of 21 months, estimated 24-month PFS and overall survival rates were 71% (95% confidence interval, 49%-84%) and 75% (51%-88%). The primary PFS endpoint has exceeded the hypothesis and its median has not been reached. Toxicities were typical of radiotherapy; however, high rates of grade 3/4 lymphopenia (58.6%) were observed. Flow cytometry revealed a relative decline in CD4 T cells and B cells, but not CD8 T cells. Upon treatment, frequencies of transitional B cells and tissue-like memory B cells increased, while resting memory B cells decreased. Patients with progression had greater percentages of baseline naïve B cells and fewer marginal zone B cells. CONCLUSIONS: Pembrolizumab and radiotherapy is efficacious in LA-HNSCC and should be evaluated in a randomized trial. The observed changes in B-cell markers deserve further study both as potential biomarkers and as therapeutic targets.