Head and neck cancer (HNC) treatments have been based on single or multimodal therapies with surgery, radiotherapy (RT), chemotherapy, and immunotherapy. However, treatment recommendations among countries may differ due to technological/human resources and usual local practices. This scoping review aims to identify, compare, and map the clinical practice guidelines (CPGs) for treating squamous cell carcinoma (SCC) of the oral cavity, oropharynx, and larynx worldwide. A search strategy on global CPGs for HNC was performed by using five electronic databases and grey literature. CPGs were selected for inclusion using EndNote-20 and Rayyan online software. No language or publication date restrictions were applied. The results were analyzed descriptively considering the most updated CPG version. In total, 25 CPGs covering the head and neck region (10), the larynx (7), the oral cavity (5), and the oropharynx (3), were found in 13 geographical regions, and 19 were developed by medical societies from 1996 to 2023. Surgery and RT remain the main modalities for early-stage HNC, with surgery preferred in low-resource countries, and RT in selected cases, especially in the larynx/oropharynx aiming to achieve a cure with organ preservation. Human papillomavirus infection for oropharyngeal SCC is not tested in some Asian countries and there is still no consensus to treat p16-positive cases differently from p16-negative. Recommendations for larynx preservation vary according to facilities in each country, however, individualized choice is emphasized. Inequality across countries/continents is evident, with a similar pattern of recommendations among developed as well as developing ones. No CPGs were found in Latin America as well as Oceania countries, where the incidence of HNC is high and limitations of access to treatment may be encountered.

The National Comprehensive Cancer Network (NCCN) describes the presence of extracapsular spread and/or positive margins in oropharynx cancer (OPC) as an indication for the addition of chemotherapy to postoperative radiation. The guideline\'s category 1 consensus is based on what they term high-level evidence. For this study, the authors performed a critical appraisal of the research upon which the NCCN guideline is based and assessed its relevance in the era of human papillomavirus (HPV)/p16-positive OPC. Multiple shortcomings were identified, including patient exclusion after randomization and the use of unplanned subgroup analyses without multivariate adjustment, which undermined internal validity. Indeterminate HPV/p16 status limited external validity. Given the unique biology of HPV/p16-positive tumors and the problems of internal and external validity, the authors concluded that the literature upon which the recommendation for the addition of chemotherapy to adjuvant radiation was based does not generate high-level evidence, and its relevance for the postoperative management of patients with HPV/p16-positive OPC remains unknown.