Secondary Acquired Nasolacrimal Duct Obstruction as a Specific Complication of Treatment With Radioactive Iodine (Morphological Study)

Update on lacrimal apparatus dysfunction associated with differentiated thyroid cancer after I-131 therapy

PURPOSE

The most prevalent lacrimal apparatus dysfunctions associated with differentiated thyroid cancer(DTC) after I-131 therapy are dry eye and nasolacrimal duct obstruction(NLDO), leading to ocular discomfort and lower quality of life for patients. It is crucial to diagnose and manage lacrimal apparatus dysfunction associated with I-131 therapy for DTC. Therefore, this review aims to comprehensively summarize and analyze the advances in mechanisms and therapeutic options underlying lacrimal apparatus dysfunction induced by I-131 therapy for DTC.

METHODS

A comprehensive search of CNKI, PubMed, and Wed of Science was performed from the database to December of 2023. Key search terms were "Thyroid cancer", "I-131", "Complications", "Dry eye", "Epiphora", "Tear", "Nasolacrimal duct" and "NLDO".

RESULTS

The research indicates that I-131 therapy for DTC causes damage to the lacrimal glands and nasolacrimal duct system, resulting in symptoms such as dry eye, epiphora, and mucoid secretions. Moreover, recent research has focused on exploring relevant risk factors of the condition and experimental and clinical treatments. However, there is some controversy regarding the mechanisms involved, whether it is due to the passive flow of I-131 in tears, active uptake of I-131 by the sodium-iodide symporter (NIS) in the lacrimal sac and nasolacrimal duct, or secondary metabolic and hormonal disturbances caused by I-131.

CONCLUSION

It is crucial for early detection and preventive measures by ophthalmologists and the need for further studies to elucidate the mechanisms underlying the disease.

Dynamic viscosity of the wall of the lacrimal sac in disorders of the patency of the lacrimal ducts

PURPOSE

To assess the dynamic viscosity of the lacrimal sac wall in patients with various origins of lacrimal duct obstruction.

METHODS

The study was performed in 35 cases: 21 cases with primary nasolacrimal duct obstruction (PANDO) and 14 cases with secondary nasolacrimal duct obstruction after radioiodine therapy (SALDO). The study of biomechanical properties of the lacrimal sac was carried out using a test bench. The principle of the study was to indent the sample at a given speed and record the data obtained from the sensor of the force transmitted to the sample. The area under the curve (AUC) and the peak viscosity were calculated. A qualitative characteristic of the obtained curve was given.

RESULTS

Median AUC in patients with PANDO was 17 × 106 [6 × 106; 19 × 106] N/m2 × s, in patients with SALDO 21 × 106 [13 × 106; 25 × 106] N/m2 × s. Intergroup differences were statistically significant (p = 0,048). The median peak viscosity in PANDO patients was 29 × 106 [25 × 106; 35 × 106] N/m2, in patients with SALDO 32 × 106 [21 × 106; 41 × 106] N/m2. The qualitative characteristics of the obtained curves differed.

CONCLUSION

Biomechanical properties of the lacrimal sac may vary depending on the cause of obliteration of the lacrimal ducts. The integrated dynamic viscosity is significantly higher in SALDO patients due to exposure to radioiodine compared to that in PANDO patients.

Topical Application of Perchlorate: A Toxicity Study in Rats

PURPOSE

To investigate the ocular safety profile of topical perchlorate as a potential preventive treatment for nasolacrimal obstruction associated with excessive use of radioactive iodine therapy.

METHODS

Nine Wistar male rats (18 eyes) were randomly assigned to receive an ocular application (topical eye drop on the OD, 3 times a day for 5 days) consisting of either: 1) sterile saline solution, 2) 30 mg/ml NaClO4 or 3) 30 mg/ml KClO4. The rat eyes were examined daily for corneal cloudiness/clarity, discharge, mucous secretions, conjunctival injection, eyelid erythema, and/or changes in behavior. Seven days after the first dose, the rats were euthanized and OU were harvested, fixed, embedded in paraffin, and stained with H&E and Masson's trichrome using standard techniques.

RESULTS

The data collected over the 7 days revealed no behavior changes or ocular complications in any of the 3 study groups. Pathologic analysis of the corneas revealed normal findings on all groups without signs of inflammation, fibrosis, or any other abnormality, and no difference between the treated and control eyes.

CONCLUSIONS

The findings of this study suggest that the use of topical perchlorate is safe to use on eyes in high concentrations. The efficacy of this compound in minimizing fibrosis of the nasolacrimal sac and duct warrants further study.

[The lacrimal apparatus as an organ at risk during radionuclide therapy]

Within the framework of the article, the authors analyzed the available information about the damage to the lacrimal apparatus during radionuclide therapy. In focus of article lesions of the lacrimal production system, the main and accessory lacrimal glands, as well as lacrimal drainage are considered. It was found that damage to the lacrimal apparatus is characteristic of 131I therapy for thyroid cancer, as well as for radioligand therapy using anti-PSMA antibodies labeled with 177Lu and 225Ac. 177Lu-PSMA and 225Ac-PSMA may damage the lacrimal gland with the formation of a clinically pronounced "dry eye syndrome". The pathogenesis of such lesions is associated with the accumulation of a radioisotope in the tissues of the lacrimal apparatus, while during therapy with 131I, accumulation is realized due to the expression of the sodium-iodine symporter in the nasolacrimal duct, and during therapy with 177Lu-PSMA and 225Ac-PSMA, the radiobiological effect is realized in connection with the expression PSMA by lacrimal tissue. An analysis of the available sources showed that to date there are no results of systematic studies on the problem, there is a lack of knowledge regarding the individual risks of developing these complications, methods for their prevention that have proven effectiveness have not been developed, and the treatment methods used, having relatively low efficiency, are not specialized. The authors concluded that the strengthening of interdisciplinary interaction, as well as the organization verification methodology and correct studies, can contribute to solving problems related to the study of the complications under consideration.

[Dacryocystorhinostomy with a counteropening in the treatment of secondary nasolacrimal duct obstruction after radioiodine therapy]

Among secondary forms of nasolacrimal duct obstruction caused by radioactive iodine therapy, its distal forms localized in the area of the Hasner's valve are predominant. In this regard, during dacryocystorhinostomy (DCR) there is a high probability of developing the sump syndrome, for which the anatomical prerequisite is that the lower edge of the DCR ostium is above the level of obstruction. In such cases, we propose to supplement DCR with a counteropening in the area of the Hasner's valve.

PURPOSE

This study analyzes the clinical effectiveness of dacryocystorinostomy with a counteropening.

MATERIAL AND METHODS

The outcomes of 49 surgeries (49 patients) with secondary acquired nasolacrimal duct obstruction due to radioactive iodine therapy were analyzed, including 34 DCR and 15 DCR with a counteropening. The clinical outcomes were analyzed over the longest possible period after surgery. The analysis included the severity of tearing on the Munk scale, the characteristic of the formed ostium on the M. Ali scale and the height of the tear meniscus. Differences were considered significant at a confidence level of 95% (p≤0.05).

RESULTS

Analysis of the results of the performed surgeries showed that DCR was clinically effective in 30 (88%) cases, DCR with a counteropening - in 15 (100%) cases. The differences were not statistically significant in the total sample, but were statistically significant when comparing the results of surgeries in patients with distal obliteration.

CONCLUSION

The developed and clinically tested method of DCR with a counteropening in the area of the Hasner's valve was completely effective in 15 patients with secondary nasolacrimal duct obstruction caused by radioiodine therapy.

Topographic and anatomical features of the nasolacrimal duct obstruction due to radioiodine treatment

PURPOSE

To investigate the topographic and anatomical features of secondary acquired nasolacrimal duct obstruction (SALDO) due to radioiodine therapy.

METHODS

Dacryocystography-computed tomography (DCG-CT) scans of the nasolacrimal ducts in 64 cases with SALDO due to radioiodine therapy and in 69 cases with primary acquired nasolacrimal duct obstruction (PANDO) were studied. The anatomical site of obstruction was located, and morphometric characteristics of the nasolacrimal ducts were calculated: volume, length, and average sectional area. The statistical analysis was performed using the t-criterion, ROC analysis, and the odds ratio (OR).

RESULTS

The mean nasolacrimal section area was 10.7 ± 0.8 mm² in patients with PANDO and 13.2 ± 0.9 mm² in patients with SALDO due to radioiodine therapy (p = 0.039); the AUC value in ROC analysis for this parameter was 0.607 (p = 0.037). The development of "proximal" obstruction including lacrimal canaliculi obstruction and obstruction at the site of the lacrimal sac was 4.076 times more likely (CI: 1.967-8.443) in patients with PANDO than in patients with SALDO due to radioactive iodine exposure.

CONCLUSIONS

By comparing CT scans of the nasolacrimal ducts, we observed that in SALDO obstruction due to radioactive iodine therapy is predominantly "distal," while in PANDO it is more often "proximal." The development of obstruction within SALDO is followed by more pronounced suprastenotic ectasia.

Dependence of radioactive iodine-131 capture by the lacrimal ducts on the tear production level

Purpose

Secondary acquired lacrimal duct obstruction (SALDO) is one of the complications of radioiodine therapy. SALDO is formed a few months after therapy if there is a sufficient uptake of radioactive iodine by the nasolacrimal duct. To date, risk factors leading to SALDO are unclear. The objective was to determine the correlation between the tear production level and radioactive iodine-131 uptake in the lacrimal ducts.

Methods

Basal and reflex tear production was studied in 64 eyes prior to the therapy with radioactive iodine-131 after drug-induced hypothyroidism. The condition of the ocular surface was assessed using the Ocular Surface Disease Index (OSDI) questionnaire. Seventy-two hours after the radioactive iodine therapy, scintigraphy was performed, which determined the presence or absence of iodine-131 in the lacrimal ducts. T-statistics and the Mann-Whitney criterion were used to identify the differences between the groups. The differences were considered significant at P ≤ 0.05. The current tear production level in patients receiving radioiodine therapy was determined using a mathematical model.

Results

A statistically significant difference between the basal (p = 0.044) and reflex (p = 0.015) tear production levels was found in cases with and without iodine-131 uptake by the lacrimal ducts. The probable current tear production level corresponds to the sum of basal and 10-20% of reflex tear production. The uptake of iodine-131 was found regardless of the OSDI results.

Conclusion

The probability of iodine-131 uptake by the lacrimal ducts rises as the tear production level increases.

Morphological Characteristics of the Lacrimal Apparatus in its Obstruction of Various Genesis

Secondary acquired lacrimal duct obstruction (SALDO) is one of the complications of radioiodine therapy. The material was obtained during endoscopic dacryocystorhinostomy with revision of Hasner's valve in patients with PANDO (n = 7) in the distal segments of the nasolacrimal duct and in patients with SALDO (n = 7) after radioactive iodine therapy. The material was stained with hemotoxylin and eosin, alcyan blue, and by Masson method. Morphological and morphometric analyses were performed in semi-automatic mode. The results of histochemical staining of sections were translated into points taking into account the area and optical density (chromogenicity). The differences were considered significant at p < 0.05. It was shown that the nasolacrimal duct sclerosis is significantly lower (p = 0.029) in patients with SALDO than in patients with PANDO while fibrosis in the lacrimal sac is the same in patients of the compared groups.

[Disorders of lacrimal drainage: the way from theory to practice]

The article summarizes the results of research conducted over the past decade concerning the current problems of dacryology, analyzes the improvements made to the methods of diagnostics used in disorders of lacrimal passages on the basis of modern imaging and functional studies, describes the techniques aimed at improving the clinical effectiveness of the intervention, as well as drug and non-drug methods of intraoperative prevention of excessive scarring in the area of the artificial ostium. The article also analyzes the experience of using balloon dacryoplasty in relapses of tear duct obstruction after dacryocystorhinostomy, and presents the modern minimally invasive surgical techniques, including nasolacrimal duct intubation, as well as balloon dacryoplasty and endoscopic plastic surgery of the ostium of the nasolacrimal duct. Additionally, the work lists the fundamental and applied tasks of dacryology and outlines promising directions of its development.

Clinical and Demographic Characteristics of Tearing in Patients after Radioiodine Ablation for Differentiated Thyroid Cancer

Background: Radioiodine ablation is a frequent procedure for the management of thyroid cancer. In several cases, this treatment is followed by secondary acquired nasolacrimal duct obstruction (SALDO). Risk factors for the development of SALDO are not defined yet.Aim - to provide clinical and demographic characteristics of tearing in patients after radioiodine treatment.Materials and methods: Material was obtained by a phone survey of 588 patients who underwent radioiodine treatment. Age and gender of the respondent, strength of administered medication, and time since the end of treatment were taken into account. Patients were asked if they had dry mouth and/or tearing at the time of the survey. Differences in values were found using parametric and nonparametric criteria, Pearson's χ² test. Differences were considered statistically significant at p ≤ 0.05.Results: Severe tearing was reported by 8.8% of patients after single-dose radioiodine treatment and 23.9% of patients after repeated one. The age of patients with severe tearing and without it showed statistically significant difference in patients after single-dose radioiodine treatment and no statistically significant difference in patients after repeated radioiodine treatment. Administration of 4 GBq or more in patients aged 61-71 years results in 4-fold increase of the risk of severe tearing. Dry mouth causes 3.6-fold increase of the risk of developing severe tearing.Conclusion: Finding risk factors for SALDO development after radioiodine therapy in the future will contribute to an individualized approach to the prevention of this complication. Development of preventive measures is one of the tasks facing researchers.