AFRS is a subset of polypoid chronic rhinosinusitis. Fokkens et al. in 2020 concluded that type I hypersensitivity and fungi on staining were the two key factors in Bent and Kuhn criteria for AFRS to be distinguished from other forms of chronic rhinosinusitis with nasal polyps (CRSwNP).10 Ideally all five of the major criteria in the original Bent-Kuhn diagnostic criteria should be met to make the diagnosis.9 The type 2 T-cell response to fungi caused an intense local allergic inflammatory reaction resulting in accumulating eosinophilic mucin.4,5,10 The typical peanut-buttery allergic mucins and nasal polyps block the drainage of the paranasal sinuses, which persist and aggravate the disease.
In this study, the incidence of AFRS out of CRS was 7.0%, which was relatively lower compared with some reports from Western countries, maybe the difference in culture species. In the hot and humid climate of the southern United States including the lower portion of the Mississippi River region, the rate of AFRS ranged from 10% to 23%.11 In the same East Asian origin, the incidence of Japanese was 1.4%. The possible reason may be regional and ethnic differences. Patients with AFRS have a distinct clinical pattern of recurrent nasal polyposis and accumulation of fungal mucins. It has been reported in the literature that the recurrence rate of this kind of non-invasive fungal rhinosinusitis is 10 %~100%.1-3 In this present small limitable sample, the recurrence rate was 26.3%. Available studies on the recurrence of AFRS tend to focus on the medical treatments, surgical techniques, degrees of allergy, and inadequate follow-up as relapse risk factors.5,9 However, at present there are few reports on the use of certain predictors to identify the AFRS patients at a high risk of relapse, especially on the basis of AFRS’ clinical manifestations. The focus of this study was to identify the key clinical manifestations needed to predict relapse of ARFS, which will provide more effective, personalized postoperative disease management to patients at a high risk of recurrence. The results from this study showed that AFRS patients with young age of onset, long duration of symptoms, and high Lund-MacKay scores were at a high risk of relapse.
Younger age of onset of AFRS patients was significantly associated with postoperative recurrence. A lot of the literature suggested that AFRS patients were young with a mean age from 20 to 40 years.3-5 In this study, the mean age was 40.5 years (SD: 14.2). Further analysis revealed that the mean age of relapsing group was 28.0 years (SD: 12.2) and the non-relapsing group was 45.0 years (SD:12.4). There was a statistically significant difference in age between the relapsing group and the non-relapsing group (p = 0.017), which indicated that AFRS patients with young age were more likely to relapse. Patro et al. also reported that AFRS was more aggressive in children compared with adults having increased recurrence rates because of responding less well to treatments.12 These findings suggested that early intervention was needed to prevent the development of CRSwNP or AFRS in young patients with allergic rhinitis. Rational postoperative follow-up protocols and medical treatments were adopted for young patients with AFRS to avoid recurrence.
Longer preoperative duration of symptoms in AFRS patients was significantly associated with postoperative recurrence. In this study, the preoperative duration of symptoms in AFRS patients was 48.0 months (14~120 months) in the relapsing group and 5.5 months (3~6 months) in the non-relapsing group. There was a statistically significant difference in duration of symptoms (p = 0.027) between the relapsing group and the non-relapsing group. Further statistical analysis showed that the duration of symptoms (p = 0.033, AUC=0.829) has significant value for predicting the recurrence of AFRS. The best cut-off value was 15 months, and the sensitivity and specificity were 80.0% and 85.7%, respectively. It may indicate that AFRS patients with a long duration of symptoms (≥15 months) are more likely to relapse.
The longer the duration of symptoms, the more severe the allergic inflammation in the paranasal sinuses. Type I hypersensitivity to a fungal antigen results in a chronic eosinophilic inflammatory process, accumulation of allergic mucin, the formation of nasal polyps and mucosal edema.5,6 Some studies suggested that postoperative systemic and topical nasal steroids could be recommended in the medical treatments of AFRS in order to eliminate the inflammatory response and have an immunomodulatory effect.4-6 A study also found that nebulized budesonide (topical steroids) treatment could reduce the recurrence rate for patients with AFRS after ESS.13 Therefore, in order to reduce the chance of recurrence by eliminating inflammation, it is suggested to adopt postoperative systemic and topical nasal steroid treatments for AFRS patients with a long duration of symptoms (≥15 months).
A higher total Lund-MacKay CT score was significantly associated with postoperative recurrence. A typical AFRS patient’s paranasal sinus CT image has high density shadows and a ground-glass feature evenly distributed throughout the sinus cavity (Figure 1). In other studies, the lesions in these images are predominantly unilateral.9,14 In this study, there were 11 cases of unilateral lesions (57.9%) and 8 cases of bilateral lesions (42.1%). The mean of the Lund-MacKay CT scores of the AFRS patients in this series was 7.53 to the left, 7.05 to the right, and the total was 14.58. The statistical analysis found a significant difference in total Lund-MacKay CT scores (p = 0.045) between the relapsing group and the non-relapsing group. The mean total Lund-MacKay CT score was 22 (14~23.5) for the relapsing group and 10 (8~20) for the non-relapsing group. It may reveal that AFRS patients with higher total Lund-MacKay CT scores are more likely to relapse. The total Lund-MacKay CT score (p = 0.047, AUC=0.807) has important value for predicting the recurrence of AFRS. The best cut-off value was 11, and the sensitivity and specificity were 100.0% and 64.3%, respectively.
Higher Lund-MacKay CT scores mean a wide range of lesions, more accumulation of inflammatory mucins, and a strong type I hypersensitivity to fungi. A lot of studies have suggested that the higher the Lund-MacKay CT scores are in AFRS patients, the higher their grade of polyposis, and the more extensive their surgery will be.15,16 Adequate ESS is universally accepted and the first important step in the treatment of patients with AFRS.1,5 The results of this study suggest that a more thorough ESS be adopted for AFRS patients with high Lund-MacKay CT scores (≥11) to reduce the chance of recurrence, including complete removal of the nasal polyps, total debridement of the mucin, complete opening and drainage of the paranasal sinus ostia, and so on.
Surgery as a first stage intervention for AFRS is near unquestionable recommendation. In this study, ESS requires surgical debridement and enlargement of the involved sinuses, removing the antigenic stimulation while retaining the normal mucosa. Postoperative nasal irrigation with isotonic saline and nasal corticosteroids and oral corticosteroids, and regular and careful debridement should be added to the regular follow-up appointment. Based on the evidence, postoperative treatment of AFRS is different due to different treatments having been adopted to deal with disease recurrence.5,8 Allergen immunotherapy is a lack of trials in AFRS, which has not become a conventional treatment. The studies about immunotherapy from Greenhaw et al. and Gan EC et al. have further evidence that immunotherapy can reduce surgical revision in atopic individuals with AFRS like AR and asthma in AFRS patients.17,18 Limited data exists to support regular use of topical or systemic antifungal agents in AFRS. One study by Seiberling recognized that itraconzole has anti-inflammatory effects in recalcitrant fungal sinusitis.19 The potential of biologics can be considered as a novel upcoming therapy for the recurrent AFRS patients. One study by Gan EC et al.20 has already been published on Omalizumab therapy (anti-IgE) for refractory AFRS with moderate or severe asthma.
In this study, two patients experienced recurrence again during follow-up. Their duration of symptoms was more than 15 months, and their total Lund-MacKay CT scores were over 11, which is consistent with the conclusion of this study that AFRS patients with a long duration of symptoms (≥15 months) and high Lund-MacKay CT scores (≥11) were at a high risk of AFRS relapse.
In conclusion, it is important to analyze the distinguishing clinical manifestations of AFRS patients and identify early the high-risk factors of postoperative recurrence. These preliminary results supported the conclusion that AFRS patients with young age of onset, long duration of symptoms (≥15 months) and high Lund-MacKay CT scores (≥11) were at a high risk of relapse. Our very preliminary data support that age of onset, duration of disease, and total Lund-MacKay CT scores of AFRS patients should be tested in further prospective and larger investigations as part of the preoperative work-up in order to develop a reasonable treatment plan and provide these patients with precise prognostic information.
Currently, there have been not a recognized and comprehensive prognostic evaluation system to manage AFRS patients after operating. We have been conducting a preliminary analysis of the postoperative AFRS patients and their recurrence requiring surgical revision in our study for the past 8 years, so as to find out the clinical characteristics of the patients to predict and judge the postoperative recurrence of AFRS requiring surgery in advance, such as what the Lund-MacKay scores is greater than can be listed as a risk factor. The highlight of this study is that it is the first idea to construct such an evaluation system. However, at present, we only analyzed the clinical characteristics of AFRS patients. In the follow-up studies, we will gradually improve the laboratory evaluation to look at other inflammatory mediators in the tissue and in the blood. Because AFRS is less prevalent in Asian populations, the size of sample of this study is small, we will take longer time and more patience to collect cases in our department. If possible, we hope to conduct this study in multiple regions and multiple centers for a larger number of clinical data and further collection in the future work.