Abstract
Treatment of locoregionally advanced head and neck squamous cell carcinoma involves a multidisciplinary approach that combines surgery, radiotherapy, and systemic therapy. These curative strategies are associated with significant acute and long-term toxicities. With the emergence of human papillomavirus (HPV) as an etiologic factor associated primarily with oropharyngeal squamous cell carcinoma, higher cure rates juxtaposed with substantial treatment-related morbidity and mortality has led to interest in de-escalated therapeutic strategies, with the goal of optimizing oncologic outcomes while reducing treatment-related toxicity. Currently explored strategies include replacing, reducing, or omitting cytotoxic chemotherapy; reducing dose or volume of radiotherapy; and incorporation of less-invasive surgical approaches. Potential biomarkers to select patients for treatment de-escalation include clinical risk stratification, adjuvant de-escalation based on pathologic features, response to induction therapy, and molecular markers. The optimal patient selection and de-escalation strategy is critically important in the evolving treatment of locoregional head and neck cancer. Recently, two large phase III trials, RTOG 1016 and De-ESCALaTE, failed to de-escalate treatment in HPV-associated head and neck cancer by demonstrating inferior outcomes by replacing cisplatin with cetuximab in combination with radiation. This serves as a cautionary tale in the future design of de-escalation trials in this patient population, which will need to leverage toxicity and efficacy endpoints. Our review summarizes completed and ongoing de-escalation trials in head and neck cancer, with particular emphasis on biomarkers for patient selection and clinical trial design. IMPLICATIONS FOR PRACTICE: The toxicity associated with standard multimodality treatment for head and neck cancer underscores the need to seek less-intensive therapies with a reduced long-term symptom burden through de-escalated treatment paradigms that minimize toxicity while maintaining oncologic control in appropriately selected patients. Controversy regarding the optimal de-escalation strategy and criteria for patient selection for de-escalated therapy has led to multiple parallel strategies undergoing clinical investigation. Well-designed trials that optimize multimodal strategies are needed. Given the absence of positive randomized trials testing de-escalated therapy to date, practicing oncologists should exercise caution and administer established standard-of-care therapy outside the context of a clinical trial.