Management of Pulmonary Nodules in Non-High-Risk Population: Initial Evidence from a Real-World Prospective Cohort Study in China
Lung cancer remains the leading cause of cancer-related deaths worldwide. Low-dose computed tomography (CT) screening has been proven to significantly reduce lung cancer mortality. However, current screening guidelines primarily focus on high-risk populations, typically elderly smokers. This approach overlooks a substantial group of lung cancer patients who are young and non-smokers. Non-smoking lung cancer is now considered an independent disease and the seventh leading cause of cancer mortality. The question of whether non-high-risk individuals should be included in screening and management protocols remains unanswered. This study aims to provide initial evidence on the incidence and characteristics of lung cancer in non-high-risk populations through a real-world prospective cohort study conducted in China.
Study Design and Methodology
The study was initiated by West China Hospital of Sichuan University and enrolled participants who underwent CT scanning for routine physical examinations or other clinical reasons. Ethical approval was obtained, and informed consent was secured from all participants. The study included individuals with non-calcified nodules of 4 mm or larger in diameter or suspicious lesions in the trachea or bronchus. Participants were categorized into non-high-risk and high-risk groups based on the Chinese Expert Consensus on Diagnosis and Treatment of Pulmonary Nodules (2018 Edition). The high-risk population was defined as individuals over 40 years old with specific risk factors such as smoking history, occupational exposure, chronic pulmonary diseases, or a family history of lung cancer.
Participant Characteristics
Between April 2018 and September 2020, 2173 subjects with positive CT findings were invited to participate. After excluding four volunteers who failed to complete the questionnaires, 2169 participants were included in the analysis. Of these, 1368 (63.07%) were classified as non-high-risk, and 801 (36.93%) as high-risk. A total of 2196 positive lung nodules were detected in the non-high-risk group, compared to 1374 in the high-risk group.
Lung Cancer Detection and Characteristics
During the follow-up period, 449 cases were confirmed by pathological examinations, including 303 in the non-high-risk group and 146 in the high-risk group. Among these, 390 were diagnosed with lung cancer (86.86%), and 59 had benign diseases (13.14%). The lung cancer detection rate in the non-high-risk group was 19.30% (264/1368), significantly higher than the 15.73% (126/801) in the high-risk group. This finding challenges the conventional focus on high-risk populations for lung cancer screening.
The mean age of lung cancer patients in the non-high-risk group was 51.89 ± 11.48 years, significantly younger than the 57.28 ± 9.34 years in the high-risk group. Notably, 44 lung cancer patients (16.67%) in the non-high-risk group were under 40 years old, accounting for 11.28% of all detected lung cancers. Additionally, the proportion of female lung cancer patients was higher in the non-high-risk group (77.27% vs. 50.00%).
Nodule Characteristics and Clinical Stages
The majority of cancerous nodules in both groups were subsolid, with pure ground glass nodules accounting for over 50% of cases. The clinical stages of detected lung cancers were predominantly stage I, with 92.05% in the non-high-risk group and 94.44% in the high-risk group. The pathological types were predominantly lung adenocarcinoma, with no significant difference between the two groups.
Implications for Screening and Management
The study revealed that 61.51% of positive pulmonary nodules and 67.69% of lung cancer cases were found in the non-high-risk group. This suggests that focusing solely on high-risk populations would result in missing a significant proportion of lung cancer cases. The high detection rate of early-stage lung cancer in the non-high-risk group underscores the importance of including this population in screening protocols.
Limitations and Future Directions
The study has several limitations, including its single-center, real-world design and the relatively short follow-up period. Additionally, the participants may not be representative of the general Chinese population due to the hospital’s high socioeconomic status. Despite these limitations, the findings highlight the need for further exploration of lung cancer screening in non-high-risk populations.
Conclusion
This study provides compelling evidence that lung cancer screening and pulmonary nodule management should not be limited to high-risk populations. The significant proportion of lung cancer cases detected in non-high-risk individuals, particularly younger patients and women, calls for a reevaluation of current screening guidelines. Future research should aim to establish appropriate screening intervals and protocols for non-high-risk populations to ensure early detection and effective management of lung cancer.
doi.org/10.1097/CM9.0000000000001848
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