With the enhancement of people's health awareness, the improvement of awareness of pulmonary nodules, and the wide application of low-dose spiral CT in clinical practice, the detection rate of pulmonary nodules is also increasing year by year. Clinically, GGN that disappears after 3 months of follow-up is called transient GGN, and those that do not disappear are called persistent GGN.
For persistent GGN, many patients face the problem of requiring long-term follow-up of pulmonary nodules. But many patients face such problems:
This doctor said that the six-month re-examination, and the other doctor said that the re-examination should be done in one year, who should be listened to?
In fact, the question of the follow-up interval for pulmonary nodules is a problem that confuses many patients and even doctors. Among them, the differences in clinical individualization factors and compliance with guidelines are important reasons affecting the judgment of different doctors.
Differences in guidelines
At present, there are many follow-up guidelines and consensus on pulmonary nodules, but the guidelines and consensus issued at different times and in different regions are often not completely consistent.
This is mainly due to the fact that the guidelines are constantly being updated as the understanding of nodules continues to deepen. On the other hand, there are also differences in the behavioral characteristics of tumors in different ethnic groups, leading to different tendencies in guidelines: in general, guidelines in Europe and the United States are more lenient, while those in Asia are more cautious.
For example, for pure ground-glass nodules < 6 mm, European and American guidelines often do not require follow-up, and Asian guidelines often recommend annual follow-up, which may be related to higher malignancy and indolence of pulmonary nodules in Asian populations.
Although guidelines vary, most develop follow-up strategies based primarily on nodule diameter, solid composition, and growth rate. Here are two guidelines briefly.
1
U.S. NCCN Guidelines:
The 2024 NCCN guidelines classify nodules into solid nodules and subsolid nodules.
Among them, solid nodules were followed up at different intervals according to the degree of risk and the diameter of the nodules (the cut-off line was 6 mm and 8 mm).
Subsolid nodules were divided into single pure ground-glass nodules, single partial solid nodules and multiple solid nodules, and different follow-up intervals were taken according to the diameter of the nodules (the dividing line was 6 mm).
Click image to enlarge the guide for more information
2
Among the domestic guidelines, the commonly used CSCO guidelines have not yet made clear recommendations for follow-up intervals
Here is a copy of the expert consensus "Chinese Expert Consensus on Multidisciplinary Minimally Invasive Diagnosis and Treatment of Pulmonary Nodules" released in 2023 for reference.
Click image to enlarge the guide for more information
Individualized factors
In fact, most clinicians tend to manage these detected nodules based on their own experience interpreting CT images and the clinical characteristics of different patients, as the risk varies from patient to patient and from nodule to nodule.
Factors that are currently high risk for the growth of nodules with high recognition include:
1
Older age
2
Has a history of malignancy, particularly prior lung cancer
3
Smoking (debatable)
Many studies have shown that lung nodules in Chinese and even East Asian populations do not grow more easily in smokers than in nonsmokers
4
CT factors
It mainly includes size, solid composition, morphological irregularity, lobulation, vacuolar sign, vascular sign, etc
In addition, the cost of processing varies from location to location. For example, if a deep nodule is to be completely removed, a lot of normal lung tissue needs to be removed. As a result, when the risk of malignant nodules is low, surgeons often prefer follow-up rather than surgery.
Trivia – Tumor growth patterns
Outpatients often ask a question: Does the tumor grow at a uniform rate? Will the growth suddenly accelerate after a follow-up visit every six months?
In fact, tumors are formed by indefinite cell division, i.e., from 1 to 2, 2 to 4, and 4 to 8...... As a result, the tumor neither grows at a uniform rate nor "accelerates suddenly", but grows exponentially.
Recent studies have shown that for pathologically confirmed AAH (dysplasia)/AIS (carcinoma in situ)/MIA (minimally invasive adenocarcinoma) nodules, the volume remains almost constant for the first 2 years, and then there is a significant increase in volume, with most malignant small nodules doubling in volume for more than 400 days, especially in East Asian populations.
Therefore, many scholars advocate that long-term follow-up is still required even in low-risk populations where the nodule is stable and < 6 mm.
summary
There is a lack of global consensus on the follow-up interval for persistent pulmonary nodules, and a combination of guideline recommendations and patient-specific factors needs to be considered. In general, the larger the nodule, the more solid components, and the more high-risk factors, the shorter the follow-up interval.
For patients, it is recommended to follow the individualized follow-up plan formulated by the attending doctor, and avoid prolonging the follow-up interval or even not following up without permission because of fear of trouble, because early detection and timely treatment of lung cancer are the key to improving the prognosis.
[1] Zhang Z, Zhou L, Yang F, Li X. The natural growth history of persistent pulmonary subsolid nodules: Radiology, genetics, and clinical management. Front Oncol. 2022;12:1011712. Published 2022 Dec 8. doi:10.3389/fonc.2022.1011712
[2] Chinese Expert Consensus on Multidisciplinary Minimally Invasive Diagnosis and Treatment of Pulmonary Nodules, 2023
[3] NCCN非小细胞肺癌指南，2024 v1
[4] Kakinuma R, Noguchi M, Ashizawa K, et al. Natural History of Pulmonary Subsolid Nodules: A Prospective Multicenter Study. J Thorac Oncol. 2016; 11(7):1012-1028. doi:10.1016/j.jtho.2016.04.006）
[5] Lee JH, Lim WH, Hong JH, Nam JG, Hwang EJ, Kim H, et al.. Growth and clinical impact of 6-mm or larger subsolid nodules after 5 years of stability at chest CT. Radiology (2020) 295(issue):448–55. doi: 10.1148/radiol.2020191921
Author: Xu Yuan, Department of Thoracic Surgery, Peking Union Medical College Hospital
Edit: Angelica does not return
This article was jointly published by Xiehe Eighth × Shanghai United Institute of Health Management