Endotypes of chronic rhinosinusitis with nasal polyps: pathology and possible therapeutic implications

Today, chronic rhinosinusitis (CRS) is a symptomatic disease diagnosed by nasal endoscopy and eventually computed tomography scan, and is treated by pharmacotherapy or, when unsuccessful, by sinus surgery. With the advent of biologics, the diagnostic approach needs to be adjusted to appreciate CRS endotypes, introducing biomarkers, and the therapeutic options will be extended by the application of biologics. Specifically, type 2 immune reactions moved into the focus, similar to asthma, involving innate and adaptive immunity pathways to establish an often severe, persistent disease. The role for endotyping of CRS became evident for biologics, but also turned out to be meaningful for the decision on the selection of pharmacotherapy and the specific surgical approach to choose. Furthermore, considerations on the role of surgery and biologics needed to be elaborated to develop decision-making processes for patients with moderate-to-severe CRS with nasal polyps, with or without comorbid asthma, allowing us to adjust the treatment for patient groups based on endotyping (precision medicine). We here aim to guide the decisions in a rational way based on the current knowledge of the efficacy and complications or side effects of the recently enlarged therapeutic options. Personal experience has been added where knowledge was lacking in this fast moving field.