Lung cancer remains one of the leading causes of cancer-related deaths in Hong Kong, with survival strongly linked to early-stage diagnosis.¹ Despite advances in imaging, many lung cancers go undetected or are diagnosed late, limiting treatment options and outcomes.^2,3 The widespread use of computed tomography (CT) has increased lung nodule detection and reduced lung cancer mortality, but adherence to management guidelines remains suboptimal.^1,2,4 A recent study led by the University of Hong Kong (HKU) found that implementation of a structured lung nodule surveillance program significantly increased the proportion of early-stage lung cancer diagnoses, highlighting its potential to improve patient survival.¹

International evidence supports that structured lung nodule surveillance can facilitate earlier diagnosis and improved outcomes; however, data on its implementation in Hong Kong have been lacking.^1,2 To address this gap, a single-center, prospective, population-based cohort study was conducted by HKU at Queen Mary Hospital to evaluate a structured lung nodule surveillance program and examine the clinical outcomes of patients recruited during its first year of implementation.¹ Between January and December 2022, 1,471 patients with lung nodules or masses attending the respiratory outpatient clinic were enrolled, after excluding those with lung cancer receiving active treatment.¹ Patients were referred mostly for incidental findings on imaging or symptomatic presentations.¹

Initial screening, risk stratification, investigations, follow-up, patient management, and education were conducted by the multidisciplinary clinical team in accordance with the 2017 Fleischner Society and Asian consensus guidelines.¹ Surveillance continued until a benign or malignant diagnosis was confirmed, or until participants declined follow-up or died.¹ Staging was assigned using the eighth edition of the International Association for the Study of Lung Cancer (IASLC) classification, with stage I-II defined as early and stage III-IV as late.¹

Among the patients enrolled, 19.8% underwent invasive diagnostic investigations, leading to the confirmation of lung cancer in 9.0% of patients.¹ Of these, 46.6% were diagnosed with stage I and 7.5% with stage II disease, resulting in 54.1% of cases being detected at an early stage.¹ This represents a 31.7% increase from the 22.4% reported by the Hong Kong Cancer Registry (HKCR) in 2021 (p<0.001), highlighting the programme’s effectiveness in identifying cancers when treatment options are most favorable.¹ Meanwhile, the proportion of stage IV cases was significantly lower at 33.8% vs. 56.9% reported by the HKCR in 2021, corresponding to a 23.1% reduction in late-stage diagnoses (p<0.001).¹ Notably, incidental nodules detected through CT accounted for 57.5% of all cases, underscoring the importance of a structured surveillance programme in complementing lung cancer screening and enabling timely diagnosis in individuals who would otherwise fall outside current screening criteria.¹

Survival analyses demonstrated that early-stage patients had markedly better outcomes than those with late-stage lung cancer (HR=12.664; 95% CI: 4.405-36.408 for progression-free survival [PFS]; HR=11.791; 95% CI: 4.132-33.651 for overall survival [OS]; both p<0.001).¹ Male patients demonstrated inferior survival compared with females (HR=2.831; 95% CI: 1.066-7.517, p=0.037 for PFS; HR=2.931, 95% CI: 1.107-7.756, p=0.030 for OS).¹ Age was also independently associated with poorer outcomes, with each additional year conferring an ~8% higher risk of progression and ~12% higher risk of death (HR=1.082; 95% CI: 1.040-1.136 for PFS; HR=1.117; 95% CI: 1.067-1.170 for OS; both p<0.001).¹ While physical attributes of lung nodules such as density or location remain important for diagnosis, they were not associated with significant survival differences in the study.¹ Taken together, these findings demonstrate the value of the programme in enabling early detection, while also identifying sex, age and disease stage as key determinants of lung cancer survival.¹

In conclusion, the lung nodule surveillance programme not only provided clinical assessments, estimated cancer risk, but also helped to optimize guideline adherence.¹ The programme enhanced follow-up compliance, facilitated timely investigations, and resulted in over half of lung cancer cases being diagnosed at an early stage.¹ Such a stage shift enabled access to curative treatments and contributed to improved survival outcomes.¹ Further research, including randomized controlled trials or case-control studies comparing enrolled with eligible non-enrolled patients, together with local cost-effectiveness evaluations, is warranted to strengthen the evidence base for wider implementation.¹

In an interview with Omnihealth Practice, Dr. Lam, Chi-Leung David, shared his insights on advancing early detection and management of lung cancer through nodule surveillance.

Q1: What are the main challenges to early lung cancer detection?

Dr. Lam: The primary challenge is that early-stage lung cancer is often asymptomatic. Because patients feel healthy, they may miss crucial follow-up appointments, leading to a delayed diagnosis. Modern screening and lung nodule surveillance programs aim to overcome this by achieving a ”stage shift,” which means finding more cancers at an early, treatable stage when curative surgery is an option, rather than at a late, symptomatic one.

Q2: What factors are prioritized when following up on a lung nodule?

Dr. Lam: When a lung nodule is detected, follow-up plans are prioritized based on the patient's age and specific nodule characteristics, such as its size and type. Part-solid nodules are considered the most concerning, followed by persistent ground-glass nodules. Ultimately, the most critical factor is any change over time, as growth or alterations in the nodule's appearance on subsequent scans may trigger immediate action like a biopsy or surgery.

Q3: How are lung cancer screening strategies evolving?

Dr. Lam: Screening is evolving beyond its traditional focus on high-risk smokers to address a rise in cases among non-smokers, particularly in Asia. A Taiwan’s large-scale study found that screening non-smokers was as effective as screening high-risk smokers in detecting early-stage cancers. It successfully achieved a ”stage shift,” demonstrating that screening non-smokers is effective for early detection. However, its broad approach is resource-intensive, highlighting the need to identify specific high-risk groups within this population for more targeted screening. A key approach now being implemented in places like Hong Kong and Singapore is performing targeted screening on individuals who have a family history of lung cancer, aiming to improve early detection in this growing patient group.