Risk of Stroke in Nasopharyngeal Cancer Survivors: A National Registry-Based Population Cohort Study

Pembrolizumab with or without bevacizumab in platinum-resistant recurrent or metastatic nasopharyngeal carcinoma: a randomised, open-label, phase 2 trial

BACKGROUND

Vascular endothelial growth factor (VEGF) is overexpressed in nasopharyngeal carcinoma and suppresses the anti-tumour immune response. Previous studies have shown that adding anti-VEGF treatment to PD-1 inhibition treatment strategies improves tumour response. We aimed to compare the efficacy of pembrolizumab, a PD-1 inhibitor, with or without bevacizumab, a VEGF inhibitor, in nasopharyngeal carcinoma.

METHODS

In this randomised, open-label, phase 2 trial done at two hospitals (National University Cancer Institute and Tan Tock Seng Hospital) in Singapore, patients with platinum-resistant recurrent or metastatic nasophayngeal carcinoma were eligible if they were aged 21 years or older and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. Patients were assigned (1:1; using random permuted blocks with varying sizes of 4 and 6) to receive either intravenous pembrolizumab (200 mg) every 21 days or a combination of pembrolizumab with intravenous bevacizumab (7·5 mg/kg) administered 1 week prior to each dose, until radiographic disease progression, unacceptable toxicity, completion of 32 cycles, or withdrawal of consent. The study was open label, therefore no masking of treatment assignment was implemented. The primary endpoint was objective response rate, assessed using RECIST (version 1.1) by independent radiologists and analysed in the intention-to-treat population (ie, all randomly assigned patients). This trial is registered with ClinicalTrials.gov, NCT03813394, and enrolment has closed.

FINDINGS

Between May 13, 2019, and Dec 6, 2023, we assessed 60 individuals for eligibility, 12 were excluded, and 48 were randomly allocated to pembrolizumab alone (n=24) or a combination of bevacizumab and pembrolizumab (n=24). The median age was 56 years (IQR 48-65), and 40 (83%) of 48 patients were male and eight (17%) were female. The median follow-up was 28·3 months (IQR 15·1-55·9). The objective response rate was significantly higher in the bevacizumab and pembrolizumab group (58·3% [95% CI 36·6-77·9] than in the pembrolizumab group (12·5% [2·7-32·4]; unadjusted RR 4·67 [95% CI 1·54-14·18]; p=0·0010). Grade 3 treatment-related adverse events occurred in two (8%) of 24 patients in the pembrolizumab group and in seven (29%) of 24 patients in the bevacizumab and pembrolizumab group; the most common severe or grade 3-4 treatment-related adverse events were thrombosis or bleeding (four [17%] of 24 patients in the bevacizumab and pembrolizumab group vs none of 24 patients in the pembrolizumab group), and others were transaminitis (none vs 1 [4%]), colitis (1 [4%] vs none]), cytopenias (none vs 1 [4%]), dermatological toxicities (1 [4%] vs none]), hypertension (1 [4%] vs none]), and proteinuria (1 [4%] vs none]). There were no grade 4 treatment-related adverse events or treatment-related deaths in either group.

INTERPRETATION

Pembrolizumab in combination with bevacizumab was more efficacious than pembrolizumab monotherapy, with manageable toxicities in platinum-resistant nasopharyngeal carcinoma. If validated in a phase 3 trial, the combination therapy could be a new standard of care in this population of patients.

FUNDING

National Medical Research Council of Singapore, National Research Foundation Singapore, Singapore Ministry of Education under its Research Centres of Excellence initiatives, and Merck Sharp & Dohme.

Carotid Artery Stenosis and Ischemic Stroke in Patients With Head and Neck Cancer Treated With Radiation Therapy: A Critical Review

The purpose of this review is to summarize the literature on carotid artery stenosis (CAS) and ischemic stroke (IS) in patients with head and neck cancer (HNC) treated with radiation therapy (RT) to guide assessment, screening, and management strategies. Patients treated with RT for HNC are at an elevated risk of developing CAS, with published meta-analyses demonstrating that CAS >50% occurs in approximately 25% of patients. Previous research suggests a 10-year cumulative incidence of stroke between 5.7% and 12.5%. Cardiovascular disease (CVD) risk prediction tools such as Qstroke, QRISK-2, and Framingham risk score perform poorly for predicting IS for patients with HNC who received RT. Duplex ultrasound is the most common imaging modality to assess CAS, but controversy remains as to the utility of screening asymptomatic individuals. Only 3 of the 5 major HNC survivorship guidelines acknowledge RT as a risk factor for CAS or IS, while only 1 makes a specific recommendation on screening for CAS (American Head and Neck Society). Within the general population, only 1 CVD guideline discusses RT as a risk factor for CAS (Society for Vascular Surgery). Clinicians involved in the care of patients with HNC treated with RT should be aware of the increased risk of CAS and IS and the challenges in risk prediction. Although there is a lack of evidence to make firm recommendations, HNC survivorship recommendations should ensure HNC survivors and primary care providers are informed of these risks and the importance of assessment and management of CVD risk factors. Future studies are required to refine risk prediction models in patients with HNC and to determine those most likely to benefit from targeted screening and initiation of early preventative strategies.

Embracing Personalized Strategies in Radiotherapy for Nasopharyngeal Carcinoma: Beyond the Conventional Bounds of Fields and Borders

Radiotherapy is the primary treatment modality for non-metastatic nasopharyngeal carcinoma (NPC) across all TN-stages. Locoregional control rates have been impressive even from the 2D radiotherapy (RT) era, except when the ability to deliver optimal dose coverage to the tumor is compromised. However, short- and long-term complications following head and neck RT are potentially debilitating, and thus, there has been much research investigating technological advances in RT delivery over the past decades, with the primary goal of limiting normal tissue damage. On this note, with a plateau in gains of therapeutic ratio by modern RT techniques, future advances have to be focused on individualization of RT, both in terms of dose prescription and the delineation of target volumes. In this review, we analyzed the guidelines and evidence related to contouring methods, and dose prescription for early and locoregionally advanced (LA-) NPC. Next, with the preference for induction chemotherapy (IC) in patients with LA-NPC, we assessed the evidence concerning radiotherapy adaptations guided by IC response, as well as functional imaging and contour changes during treatment. Finally, we discussed on RT individualization that is guided by EBV DNA assessment, and its importance in the era of combinatorial immune checkpoint blockade therapy with RT.