Exploring the pathophysiology, treatment options, and long-term outcomes of nasal polyps. A comprehensive review

Nº de DOI: 10.34896/RSI.2025.93.30.001

AUTHORS

1. Rigoberto Fabian Jaime Delgado. General Practitioner. Attached to the Center of Medical Specialties and Dentistry. Independent Researcher of the Research and Teaching Department Matilde Hidalgo of Procel. Graduate of the Eloy Alfaro Laica University. (Jipijapa-Ecuador). https://orcid.org/0009-0000-6123-4466
2. Jeniffer Johana Salguero Alarcón. General Practitioner. Attached to the Central Basic Hospital. Graduate of the Central University of Ecuador. (Quito-Ecuador). https://orcid.org/0000-0003-3849-749X
3. Kevin Horacio Illescas Ochoa. General Practitioner. Master in Health Management. Attached to the Teodoro Maldonado Carbo Hospital. Graduated from the University of Guayaquil. (Guayaquil-Ecuador). https://orcid.org/0000-0003-2272-6104
4. Nelson Daniel Gonzaga Yupangui. General Practitioner. Attached to the Santa Teresita Basic Hospital. Graduated from the University of Guayaquil. (Machala-Ecuador). https://orcid.org/0009-0008-6863-4647
5. Hans Michael Salinas Guaman. General Practitioner. Attached to María Lorena Serrano Hospital. Graduated from the Technical University of Machala. (Machala-Ecuador). https://orcid.org/0009-0001-7074-9979

ABSTRACT

This comprehensive review aims to explore the intricate pathophysiology of nasal polyps, evaluate the spectrum of treatment options available, and analyze the long-term implications for patients afflicted by this condition, thereby providing a holistic understanding of nasal polyps and their impact on health and well-being.

KEY WORDS

Nasal polyps, chronic rhinosinusitis with nasal polyps, pathophysiology of nasal polyps, treatment of nasal polyps and long-term outcomes of nasal polyp management.

RESUMEN

Esta revisión integral tiene como objetivo explorar la intrincada fisiopatología de los pólipos nasales, evaluar el espectro de opciones de tratamiento disponibles y analizar las implicaciones a largo plazo para los pacientes que padecen esta afección, proporcionando así una comprensión holística de los pólipos nasales y su impacto en la salud y el bienestar.

PALABRAS CLAVE

Pólipos nasales, rinosinusitis crónica con pólipos nasales, fisiopatología de los pólipos nasales, tratamiento de los pólipos nasales y resultados a largo plazo del manejo de los pólipos nasales.

INTRODUCTION

Nasal polyps are benign, soft tissue growths that develop in the nasal passages and sinuses, often resulting from chronic inflammation and allergic responses. Their pathophysiology is complex, involving a multifactorial interplay of inflammatory processes, genetic predispositions, and environmental triggers that lead to the proliferation of mucosal tissues. Understanding the underlying mechanisms that contribute to the formation of nasal polyps is crucial, as it not only sheds light on their etiology but also helps to identify potential therapeutic targets. Current treatment options range from pharmacological interventions, such as corticosteroids and antihistamines, to surgical procedures aimed at removing polyps and restoring normal nasal function. However, the effectiveness of these treatments can vary widely, and emerging biologic therapies hold promise for those with severe or recurrent cases. The long-term outcomes for individuals with nasal polyps can be significant, with untreated polyps leading to complications such as obstructive sleep apnea, chronic sinusitis, and diminished quality of life. Furthermore, recurrence rates post-treatment poses a considerable challenge for both patients and clinicians, necessitating ongoing research into effective management strategies. This comprehensive review aims to explore the intricate pathophysiology of nasal polyps, evaluate the spectrum of treatment options available, and analyze the long-term implications for patients afflicted by this condition, thereby providing a holistic understanding of nasal polyps and their impact on health and well-being.

OBJECTIVE

To explore the intricate pathophysiology of nasal polyps, evaluate the spectrum of treatment options available, and analyze the long-term implications for patients affected by this condition, thus providing a holistic understanding of nasal polyps and their impact on health and well-being.

METHODOLOGY

This scientific review aims to explore the pathophysiology, treatment options, and long-term outcomes associated with nasal polyps, providing a comprehensive understanding of the condition. A systematic literature search is conducted using databases such as PubMed, Scopus, and Web of Science to identify peer-reviewed articles, clinical studies, and meta-analyses. The search terms include “nasal polyps,” “chronic rhinosinusitis with nasal polyps (CRSwNP),” “pathophysiology of nasal polyps,” “treatment of nasal polyps,” and “long-term outcomes of nasal polyp management.” Articles published within the last 20 years are prioritized to capture the most recent advances in understanding and treating this condition.

The inclusion criteria for the review focus on studies that address the molecular and cellular mechanisms underlying the development of nasal polyps, such as chronic inflammation, tissue remodeling, and immune dysregulation. Research on the role of key cytokines, such as interleukins (IL-4, IL-5, IL-13), and the involvement of eosinophils in the pathogenesis of nasal polyps is particularly emphasized. Additionally, articles that discuss genetic and environmental factors contributing to the development and persistence of nasal polyps are included to provide a holistic view of the condition’s etiology.

In terms of treatment, studies evaluating pharmacological options, including intranasal corticosteroids, biologics targeting inflammatory pathways, and systemic steroids, are analyzed to determine their efficacy, safety, and suitability for different patient populations. Surgical interventions, such as functional endoscopic sinus surgery (FESS), are also reviewed to assess their role in managing refractory cases and improving patient quality of life. Articles comparing medical and surgical approaches, as well as combination therapies, are included to identify optimal treatment strategies.

Long-term outcomes are assessed through studies that track recurrence rates, symptom control, and the impact of treatments on patient-reported quality of life. Special attention is given to research that explores the role of biologics in reducing recurrence and minimizing the need for repeated surgeries. Additionally, studies on the economic burden of nasal polyps and the cost-effectiveness of emerging therapies are reviewed to provide insights into the broader implications of disease management.

Each study is critically evaluated for its methodology, sample size, and clinical relevance. Articles lacking robust data, with small sample sizes, or with high potential for bias are excluded from the review. Data are organized into three main themes: the pathophysiology of nasal polyps, treatment modalities, and long-term outcomes. Emerging trends, such as personalized medicine approaches and novel biologic therapies, are highlighted to identify future directions in the field.

This methodology ensures a thorough synthesis of current evidence, offering insights into the complex mechanisms driving nasal polyps, the efficacy of existing treatments, and strategies to improve patient outcomes. By addressing gaps in the current literature and evaluating innovative approaches, this review aims to serve as a valuable resource for clinicians and researchers seeking to enhance the management of nasal polyps.

RESULTS

Pathophysiology of Nasal Polyps:

What are the underlying mechanisms leading to the formation of nasal polyps?

The formation of nasal polyps is a multifactorial process involving a complex interplay of immunological, inflammatory, and structural changes within the nasal mucosa. Nasal polyps originate from the lining of the sinuses and are characterized by hyperplastic edematous connective tissue, which indicates an increase in tissue volume due to the accumulation of extracellular fluid¹. This swelling, particularly prominent in the region of the middle meatus, is driven by the collection of extracellular fluid, leading to the protrusion of polyps into the nasal cavity or sinuses¹. Despite the noncancerous nature of these growths, their formation is closely associated with underlying conditions such as asthma and allergies, suggesting an immune-mediated component². The presence of inflammation, primarily characterized by infiltrating neutrophils and eosinophils, plays a crucial role in the development of nasal polyps¹. Furthermore, the impaired immunological mechanisms, evidenced by the altered expression of numerous genes involved in immunological response and cellular processes, highlight the complexity and heterogeneity of the etiopathogenesis of nasal polyps³. These insights point to the necessity for a comprehensive approach to understanding and managing nasal polyps, emphasizing the need for targeted interventions addressing the various contributing factors to effectively mitigate this chronic condition.

How do inflammatory processes contribute to nasal polyp development?

The inflammatory processes that contribute to the development of nasal polyps are multifaceted and involve a complex interplay between immune responses and cellular changes in the sinonasal environment. Chronic inflammation, often associated with conditions such as chronic rhinosinusitis and allergic rhinitis, is a significant driver of nasal polyp formation⁴. This chronic inflammation leads to the recruitment and activation of eosinophils, mast cells, and lymphoid cells, which produce type 2 cytokines, further exacerbating the inflammatory milieu⁴. This inflammatory response not only causes tissue edema and the formation of pseudocysts but also promotes the accumulation of plasma proteins like albumin, which contribute to the size and growth of polyps⁴. The persistence of these inflammatory processes is a key factor in the recurrence of nasal polyps, highlighting the need for targeted treatments that address the underlying inflammatory mechanisms⁵. Understanding these interconnections is crucial for developing effective therapeutic strategies that can mitigate the impact of chronic inflammation on nasal polyp development and prevent their recurrence.

What genetic factors are associated with increased risk of nasal polyps?

Genetic predisposition plays a significant role in the development of nasal polyps, as evidenced by the heritability estimates ranging from 14% to 42%⁶. This genetic influence suggests that certain alleles may confer susceptibility to the inflammatory response that underpins the formation of these polyps. Such genetic factors could potentially affect the immune system’s regulation, leading to an inappropriate or exaggerated inflammatory response that facilitates the growth of nasal polyps⁶. Additionally, these genetic predispositions may interact with environmental factors, such as allergens or irritants, exacerbating the inflammatory processes involved in polyp formation. Understanding the genetic basis of nasal polyps is crucial, as it could lead to more targeted therapies that address the root cause of polyp development rather than solely managing symptoms⁶. This highlights the need for further genetic research to identify specific genes or genetic markers associated with an increased risk of nasal polyps, which could ultimately inform personalized treatment strategies and improve patient outcomes.

Treatment Options for Nasal Polyps

What are the current pharmacological treatments available for nasal polyps?

The current pharmacological treatments available for nasal polyps encompass a variety of strategies aimed at reducing inflammation and controlling symptoms. The first line of treatment often involves nasal corticosteroid sprays, which are effective in shrinking or even removing nasal polyps for many patients⁵. Intranasal corticosteroids are essential not only as an initial therapy but also for maintenance, as they improve nasal congestion and reduce polyp size, thereby contributing to the management of chronic rhinosinusitis with nasal polyposis⁷. For cases that do not respond to corticosteroids, biologics such as Dupilumab, which contains monoclonal antibodies, are available and have been FDA-approved for treating resistant nasal polyps and chronic sinusitis [8]. Dupilumab works by stimulating the immune system to target type 2 inflammation, which is a key factor in the development of nasal polyps^2,9. Despite its efficacy, the role of biologics in the treatment regimen, especially concerning their timing relative to surgical interventions, remains under investigation, indicating a need for further research into optimal treatment protocols⁹. Moreover, antifungal therapies, particularly Amphotericin B, present a promising alternative in managing nasal polyposis by reducing fungal load and inflammation in the sinonasal region¹⁰. These pharmacological interventions highlight the diverse approaches available for managing nasal polyps, though they also underscore the necessity for individualized treatment plans and continued investigation into long-term efficacy and safety.

How effective are surgical interventions in managing nasal polyps?

Surgical interventions play a pivotal role in managing nasal polyps, particularly when medical therapies fail to provide adequate relief or in cases where the polyps are notably large². The effectiveness of such interventions hinges on a comprehensive treatment approach that not only aims at the physical removal of the polyps but also addresses the underlying sinus issues contributing to their formation¹¹. Endoscopic surgery is frequently employed due to its minimally invasive nature and its capability to effectively excise polyps while correcting sinus problems^2,11. However, to ensure long-term success and prevent recurrence, surgical intervention should ideally be complemented with medical treatments, such as corticosteroid nasal sprays, which have been shown to help in keeping polyps from returning post-surgery¹¹. This integrated strategy underscores the importance of a tailored treatment plan that accommodates the unique characteristics of each patient’s condition¹². Therefore, while surgical interventions can be highly effective, they should be part of a broader, personalized management plan that includes both pre- and post-operative medical therapies to optimize patient outcomes.

What role do biologic therapies play in the treatment of nasal polyps?

Biologic therapies have emerged as a promising treatment option for chronic rhinosinusitis with nasal polyps (CRSwNP), particularly in cases where traditional therapies and surgical interventions have proven insufficient¹³]. While surgery remains the most effective means of reducing polyposis and improving quality of life, biologics such as dupilumab have been shown to significantly enhance patient outcomes by improving nasal polyp scores, reducing congestion, and enhancing overall quality of life¹⁴. The use of biologics is particularly recommended for patients who experience recurrence of nasal polyps post-surgery or those with severe polyp disease who have not responded to other medical management¹³. However, the long-term efficacy and cost utility of biologics in comparison to surgical options remain subjects of ongoing investigation, as the benefits can diminish after treatment cessation and the high cost poses a barrier to widespread accessibility¹⁴. Therefore, continued research and real-world evidence are needed to refine the treatment algorithms and ensure optimal patient selection and management¹³.

Long-term Outcomes of Nasal Polyps

What are the potential complications associated with untreated nasal polyps?

Untreated nasal polyps present several potential complications that can severely impact an individual’s health over time. One of the primary concerns is their capacity to grow large enough to block airways, leading to obstructive nasal symptoms that can impair sleep and contribute to chronic fatigue^7,15. This blockage not only disrupts normal breathing but can also cause long-term and severe damage to the body by facilitating other health conditions, such as infections and the formation of mucoceles due to obstructed paranasal sinuses drainage pathways^7,15. Additionally, the persistent presence of nasal polyps without treatment can result in the loss of the ability to smell, further diminishing the quality of life for affected individuals¹⁶. These complications underscore the importance of addressing nasal polyps promptly, as neglecting treatment can lead to serious health problems that may require more intensive medical interventions¹⁷. Therefore, it is crucial for individuals experiencing symptoms of nasal polyps to seek medical evaluation and management to prevent these adverse outcomes.

How do nasal polyps affect quality of life over time?

The presence and recurrence of nasal polyps significantly affect various aspects of an individual’s quality of life, often leading to a cyclical impact on both physical and emotional well-being. Despite surgical interventions aimed at alleviating symptoms, the recurrence of polyps is common and can exacerbate the frustration and distress experienced by patients, thereby diminishing their overall quality of life over time¹⁸. This recurrent nature of nasal polyps often necessitates additional surgical procedures, which, while potentially offering temporary relief, can contribute to the chronicity of the condition and its symptoms¹⁸. The physical manifestations of nasal polyps extend beyond nasal obstruction and can severely impact daily activities, such as exercise and sleep, with a significant portion of sufferers reporting difficulties in these areas¹⁹. Furthermore, the emotional toll is substantial, with many individuals experiencing mental health challenges, as the chronic and recurrent nature of the condition can contribute to a pervasive sense of anxiety and depression^18,19. Therefore, addressing nasal polyps requires a multifaceted approach that not only targets the physical symptoms but also considers the psychological and lifestyle impacts, necessitating comprehensive management strategies and potential interventions to enhance patients’ quality of life holistically.

What are the recurrence rates after treatment for nasal polyps?

The recurrence rates of nasal polyps following treatment can vary significantly based on the type of intervention used. Studies have shown that patients treated with intranasal fluticasone propionate after functional endoscopic sinus surgery (FESS) do not exhibit a significant reduction in recurrence rates compared to those receiving a placebo, indicating that this treatment may not effectively prevent recurrence in the long term²⁰. This finding aligns with the broader variability observed in the recurrence of chronic rhinosinusitis with nasal polyps (CRSwNP), which can reach as high as 55-60% in some cases²¹. Interestingly, furosemide treatment has demonstrated a potentially more favorable outcome, as initial trials reported a significant reduction in relapse rates, with only 4 cases of recurrence compared to 12 in the untreated group after six months²⁰. Furthermore, in comparison studies, the recurrence rate for furosemide was 17.5%, which was lower than the 24.2% observed with mometasone (MF), highlighting the potential efficacy of furosemide in reducing recurrence rates²⁰. These findings underscore the need for personalized treatment approaches that consider the variability in patient response and the potential benefits of alternative therapies like furosemide to more effectively manage and reduce the recurrence of nasal polyps.

DISCUSSION

The findings of this comprehensive review illuminate the multifaceted pathophysiology underlying nasal polyps and underscore the necessity for a nuanced understanding of their management. The intricate interplay between immunological and inflammatory responses, particularly the significant role of eosinophils and cytokines, reveals how chronic inflammation drives the development and recurrence of nasal polyps. This highlights the limitation of existing treatment modalities, such as intranasal corticosteroids, which may not sufficiently address the underlying inflammatory pathways, as evidenced by the lack of significant recurrence reduction in patients receiving fluticasone propionate post-functional endoscopic sinus surgery (FESS) compared to placebo. Furthermore, the differential recurrence rates observed between treatments, notably the lower recurrence rate associated with furosemide, suggest that alternative pharmacological strategies may warrant further investigation to optimize therapeutic outcomes. The genetic predisposition to nasal polyp formation, with heritability estimates ranging from 14% to 42%, presents a critical area for ongoing research, as identifying specific genetic markers could pave the way for personalized treatment approaches that directly target the mechanisms of polyp development. Additionally, the emerging role of biologic therapies and antifungal treatments, such as Amphotericin B, points to the potential for innovative strategies that not only alleviate symptoms but also address the underlying pathophysiological processes. It is essential to recognize that untreated nasal polyps can lead to significant health complications, which further emphasizes the importance of timely and effective intervention. However, the variability in patient responses to treatment remains a challenge, necessitating a tailored approach that considers individual genetic and environmental factors. Future research should focus on elucidating the precise genetic and molecular pathways involved in nasal polyp formation and exploring the efficacy of novel therapeutic agents in managing this chronic condition. By addressing these gaps in knowledge and enhancing our understanding of the interplay between environmental triggers and genetic susceptibility, we can develop more effective, personalized treatment strategies that not only manage symptoms but also reduce the burden of recurrence and improve long-term patient outcomes.

CONCLUSIONS

1. Nasal polyps represent a chronic inflammatory condition of the nasal and sinus mucosa, with significant implications for patients’ quality of life and long-term health. Advances in understanding their pathophysiology reveal that these lesions are driven by complex interactions between immune dysregulation, chronic inflammation, and tissue remodeling processes. Key molecular players, such as interleukins (IL-4, IL-5, IL-13) and eosinophilic infiltration, have been identified as central to disease development, providing potential therapeutic targets for more effective management. Additionally, genetic predisposition and environmental factors contribute to the variability in disease presentation and progression, highlighting the need for personalized approaches to treatment.
2. The management of nasal polyps has evolved considerably, with a range of pharmacological and surgical options now available. Intranasal corticosteroids remain the cornerstone of treatment, offering significant symptom relief for most patients. However, for individuals with severe or refractory disease, newer biologic therapies targeting specific inflammatory pathways, such as dupilumab and omalizumab, have shown promising results in reducing polyp size, alleviating symptoms, and lowering recurrence rates. Surgical interventions, such as functional endoscopic sinus surgery (FESS), continue to play a vital role in managing cases unresponsive to medical therapy, particularly when paired with ongoing postoperative pharmacological management to minimize recurrence.
3. Long-term outcomes in nasal polyp management have improved with these advancements, but challenges remain. Recurrence is common, particularly in patients with underlying comorbidities such as asthma or aspirin-exacerbated respiratory disease (AERD). Emerging biologic therapies offer hope for sustained control and reduced reliance on systemic corticosteroids, which carry the risk of significant side effects. Furthermore, the integration of personalized medicine into treatment planning holds promise for tailoring therapies to individual disease profiles, optimizing both efficacy and safety.

BIBLIOGRAFÍA

1. Sánchez Chóez G, Castro Sánchez JM, Sánchez Castro ML, Caza Herrera S de los A. Pólipos nasales: diagnóstico y tratamiento. RECIAMUC [Internet]. 2020 Jan 31 [cited 2024 Nov 8];4(1):220–8. Available from: https://doi.org/10.26820/reciamuc/4.(1).enero.2020.220-228
2. Cleveland Clinic. Nasal Polyps: Symptoms, Causes, Treatment & Prevention [Internet]. Cleveland Clinic. 2024 [cited 2024 Nov 9]. Available from: https://my.clevelandclinic.org/health/diseases/15250-nasal-polyps
3. Chojnowska S, Kępka A, Waszkiewicz N, Kołodziejczyk Z, Konarzewska Duchnowska E, Ościłowicz K, et al. Etiopathogenesis nasal polyps. Progress in Health Sciences [Internet]. 2013 [cited 2024 Dec 9];3(2):2013–151. Available from: https://www.umb.edu.pl/photo/pliki/progress-file/phs/phs_2013_2/151-159_chojnowska.pdf
4. Stevens WW, Schleimer RP, Chandra RK, Peters AT. Biology of nasal polyposis. The Journal of allergy and clinical immunology [Internet]. 2014 May 1 [cited 2020 Oct 27];133(5):1503-1503.e4. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422376/
5. Kim J. Nasal Polyps [Internet]. www.hopkinsmedicine.org. 2022 [cited 2024 Dec 9]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/nasal-polyps
6. Huang J, Xu Y. Autoimmunity: A New Focus on Nasal Polyps. International Journal of Molecular Sciences [Internet]. 2023 May 8 [cited 2024 Dec 9];24(9):8444–4. Available from: https://doi.org/10.3390/ijms24098444
7. del Toro E, Portela J. Nasal Polyps [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2020 [cited 2024 Dec 9]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560746/
8. Harvard Health. First medication to treat uncontrolled nasal polyps [Internet]. Harvard Health. 2020 [cited 2024 Dec 9]. Available from: https://www.health.harvard.edu/diseases-and-conditions/first-medication-to-treat-uncontrolled-nasal-polyps
9. Lança Gomes P, Miglani A, Marino MJ, Lal D. Biologics for Chronic Rhinosinusitis with Nasal Polyps [Internet]. AAO-HNS Bulletin. 2023 [cited 2024 Dec 9]. Available from: https://bulletin.entnet.org/clinical-patient-care/article/22881642/biologics-for-chronic-rhinosinusitis-with-nasal-polyps
10. Rajguru R. Nasal Polyposis: Current Trends. Indian Journal of Otolaryngology and Head & Neck Surgery [Internet]. 2014 Jan 1 [cited 2022 Nov 1];66(Suppl 1):16–21. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918342/
11. Mayo Clinic. Nasal polyps – Diagnosis and treatment [Internet]. Mayoclinic.org. 2018 [cited 2024 Dec 9]. Available from: https://www.mayoclinic.org/diseases-conditions/nasal-polyps/diagnosis-treatment/drc-20351894
12. ENT Specialists Group. Nasal Polyps Treatment Melbourne – Nasal Polyp Removal [Internet]. ENT Specialists Group. 2024 [cited 2024 Dec 9]. Available from: https://entspecialistsgroup.com.au/nasal-polyps-treatment/
13. Patel G, Peters AT. The Role of Biologics in Chronic Rhinosinusitis With Nasal Polyps. National Library of Medicine [Internet]. 2021 Jan 1 [cited 2023 May 20];100(1):44–7. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980424/
14. Morse JC, Miller C, Senior B. Management of Chronic Rhinosinusitis with Nasal Polyposis in the Era of Biologics. Journal of Asthma and Allergy [Internet]. 2021 Jul [cited 2021 Dec 7]; Volume 14(1):873–82. Available from: https://www.dovepress.com/management-of-chronic-rhinosinusitis-with-nasal-polyposis-in-the-era-o-peer-reviewed-fulltext-article-JAA
15. Selter JH. Nasal Polyps Treatment Specialist in Suffern [Internet]. Allergist Located in Suffern NY and Monroe NY | Allergy and Asthma Care of Rockland. 2024 [cited 2024 Dec 10]. Available from: https://aacrockland.com/nasal-polyps
16. Mayo Clinic. Nasal polyps – Symptoms and causes [Internet]. Mayo Clinic. 2019 [cited 2024 Dec 9]. Available from: https://www.mayoclinic.org/diseases-conditions/nasal-polyps/symptoms-causes/syc-20351888
17. 17.Kumar K, Suyog Uttekar P. What Happens if Nasal Polyps Go Untreated? 7 Complications, Cure [Internet]. MedicineNet. 2022 [cited 2024 Dec 9]. Available from: https://www.medicinenet.com/what_happens_if_nasal_polyps_go_untreated/article.htm
18. Asthma and Allergy Foundation of America. Life with Nasal Polyps [Internet]. Asthma & Allergy Foundation of America. 2024 [cited 2024 Dec 10]. Available from: https://aafa.org/asthma-allergy-research/our-research/life-with-nasal-polyps-crswnp/
19. Asthma and Allergy Foundation of America. Life with Nasal Polyps: The Patient Experience and Opportunities to Improve Care in the U.S. [Internet]. aafa.org. 2024 [cited 2024 Dec 9]. Available from: https://aafa.org/wp-content/uploads/2024/04/life-with-nasal-polyps-report.pdf
20. Rizzi A, Gammeri L, Cordiano R, Valentini M, Centrone M, Marrone S, et al. Therapeutic Strategies to Prevent the Recurrence of Nasal Polyps after Surgical Treatment: An Update and In Vitro Study on Growth Inhibition of Fibroblasts. Journal of Clinical Medicine [Internet]. 2023 Apr 13 [cited 2024 Dec 9];12(8):2841–1. Available from: https://www.mdpi.com/2077-0383/12/8/2841
21. Riva G, Tavassoli M, Cravero E, Moresco M, Albera A, Canale A, et al. Long-term evaluation of nasal polyposis recurrence: A focus on multiple relapses and nasal cytology. American Journal of Otolaryngology [Internet]. 2022 Mar [cited 2023 Mar 21];43(2):103325. Available from: https://pubmed.ncbi.nlm.nih.gov/34933163/