Significance of lung nodules detected on chest CT among adult Aboriginal Australians - a retrospective descriptive study.

INTRODUCTION: There are limited data on chest computed tomography (CT) findings in the assessment of lung nodules among adult Aboriginal Australians. In this retrospective study, we assessed lung nodules among a group of adult Aboriginal Australians in the Northern Territory of Australia. METHODS: Patients who underwent at least two chest CT scans between 2012 and 2020 among those referred to undergo lung function testing (spirometry) were included. Chest CT scans were assessed for the number, location, size and morphological characteristics of lung nodules. RESULTS: Of the 402 chest CTs assessed, 75 patients (18.7%) had lung nodules, and 57 patients were included in the final analysis with at least two CT scans available for assessment over a median follow-up of 87 weeks. Most patients (68%) were women, with a median age of 58 years and smoking history in 83%. The majority recorded only a single nodule 43 (74%). Six patients (10%) were diagnosed with malignancy, five with primary lung cancer and one with metastatic thyroid cancer. Of the 51 (90%) patients assessed to be benign, 64 nodules were identified, of which 25 (39%) resolved, 38 (59%) remained stable and one (1.8%) enlarged on follow-up. Nodules among patients with malignancy were typically initially larger and enlarged over time, had spiculated margins and were solid, showing no specific lobar predilection. CONCLUSIONS: Most lung nodules in Aboriginal Australians are likely to be benign. However, a proportion could be malignant. Further prospective studies are required for prognostication and monitoring of lung nodules in this population.

Cystic lung disease in adult Indigenous Australians in the Northern Territory of Australia.

INTRODUCTION: Indigenous Australians have a high prevalence of chronic lung diseases. However, no previous studies have reported on cystic lung disease in an Indigenous patient cohort. METHODS: This report describes 20 adult Indigenous patients noted to have incidental lung cysts on chest computed tomography (CT) while being referred to undergo lung function tests in the Northern Territory of Australia. RESULTS: Of the total 20 Indigenous patients demonstrating presence of pulmonary cysts on chest CT scan, 13/20 (65%) were males with a mean age of 49.9 years (range 24-74 years), with no significant difference in age between males and females. The majority reported a smoking history and spirometry demonstrated moderate reduction in lung function parameters. While there was no pattern in the size or location of cysts, most demonstrated multiple cysts (55% had ≥5 cysts) with bilateral involvement (65%), alongside a range of concurrent pulmonary radiological abnormalities. The aetiology for lung cysts was largely unknown. CONCLUSION: This is the first report to illustrate cystic lung disease within an Indigenous population. Further radiology studies are required to investigate the causes and prognostications of cystic lung disease in Indigenous patients.

Significance and prognostication of mediastinal lymph node enlargement on chest computed tomography among adult Indigenous Australians.

INTRODUCTION: There is a lack of data on chest computed tomography (CT) findings on mediastinal lymph node enlargement (MLE), including normal size threshold of less than 10 or 15 mm for MLE among Indigenous Australians. In this study, we assessed the significance and the applicability of the current guidelines for the threshold for abnormal MLE among adult Indigenous Australians. METHODS: Patients who underwent chest CT between 2012 and 2020 among those referred to undergo lung function test (spirometry) were assessed for the presence of MLE which were classified as Group A (no measurable nodes), Group B (<10 mm), Group C (≥10 to 14.99 mm) and Group D (≥15 mm). RESULTS: Of the total 67 patients identified to have MLE, 49 patients had at least two CT scans available for assessment over a median follow-up period of 101.3 weeks (IQR: 62.4, 235.6) and were included in the analysis. Evidence of chronic lung disease was common, with a significant proportion demonstrating either COPD or bronchiectasis and a high proportion with smoking history (93%). During the first CT scan, 34/49 (69%) had >10 mm nodes, of which 12/34 (35%) reduced in size, 22/34 (65%) remained stable, and 3/34 (9%) had malignancy on follow-up. CONCLUSION: Despite most patients demonstrating the presence of significant MLE with varying size and in most >10 mm, the majority remain stable or benign in nature and only a minor proportion showed evidence of lung malignancy. Further prospective studies are needed in the characterisation of MLE among Indigenous patients.