Ongoing and emerging research is providing a fuller picture of chronic rhinosinusitis (CRS) as a spectrum of diseases that goes beyond the current clinical phenotyping, based largely on the presence or absence of nasal polyps, to a deeper recognition of distinct subtypes of the disease based on pathogenic mechanisms.
Explore This IssueJuly 2019
It is hoped that research into these subtypes will lead to the ability to use them as biomarkers to better predict how best to treat patients with CRS, particularly given the rapid development and availability of biologic agents aimed at targeting specific pathologic mechanisms of disease.
The need for improved tailored treatments for people with CRS is highlighted by the sheer number of people with sinusitis symptoms, a limited ability to adequately treat these patients based on symptoms, and the current reliance on the presence or absence of polyps. “The epidemiology of CRS is still a work in progress, but studies suggest that a huge number of people, probably 39 million in this country, have the symptoms of chronic rhinosinusitis,” said Robert Kern, MD, chair of the department of otolaryngology–head and neck surgery at Northwestern Feinberg School of Medicine in Chicago, “Of those, I would estimate that perhaps 26 million or so really have sinusitis, confirmed by computed tomography, of which only approximately six million have polyps.”
Although targeting patients with polyps for treatment with intranasal and oral corticosteroids is the standard treatment approach, its impact on outcomes is less than satisfactory, he said. “Phenotyping or clinical evaluation alone has made only a limited impact on clinical care, or even the ability to tell a patient if they will do well or not on a given treatment,” he said.
To improve clinical outcomes, researchers like Dr. Kern are looking beyond clinical patterns of sinusitis into the patterns of tissue inflammation as a guide to better improve their ability to identify the patient subsets who will benefit from specific treatments. Called endotyping, the research looks at the underlying pathogenic mechanisms of disease, an approach that is similar to research that has already been conducted in the study of asthma and other atopic diseases.
For clinicians, this research, combined with ongoing studies into more advanced phenotyping based on attributes such as age and geography, highlights the need to look at CRS not as a singular disease, but as one with distinct clinical presentations and disparate—probably related—pathogenic mechanisms. “It is important to understand that all CRS patients are different,” said Justin H. Turner, MD, PhD, associate professor of otolaryngology–head and neck surgery at Vanderbilt University in Nashville. “CRS is a clinical syndrome, and patients may present very differently and have variable responses to medical and surgical interventions.”