How common are lung nodules? The total number of lung nodules in the country is about 120 million. In all the people who do chest CT, the detection rate of pulmonary nodules is close to 40%, the detection rate of lung nodules in people who smoke is more than 50%, and the detection rate of lung nodules in people over 50 years old who smoke for a long time or have a poor working environment can even reach about 80%.
Why are lung nodules so common?
On the one hand, it is closely related to the environment, and the rapid development of China's economy in the past few decades has brought serious environmental pollution; pulmonary nodules are also related to smoking and second-hand smoke, coupled with the impact of modern people's life pressure, anxiety, staying up late, bad habits and other factors.
On the other hand, the improvement of health awareness and the popularity of chest CT examination, the resolution of chest CT is unattainable on chest x-ray, and high-resolution thin-layer CT can even show 1 mm of tiny nodules.
How far are lung nodules from lung cancer?
In fact, more than 90% of the small nodules in the lungs found on physical examination are not lung cancer, so there is no need to panic. The vast majority of lung nodules are benign, and the probability of malignant nodules is actually only about 5%.
Benign nodules may be:
1. Scars left by bleeding from previous injuries in the lungs;
2. Chronic inflammatory proliferative foci;
3. Normal lymph nodes in the lungs;
4. Leiomyomas in the lungs;
5. Inflammatory pseudotumor;
6. Tuberculosis balls;
7. Cryptococcal infection;
…
In terms of nodule morphological density:
Pure ground glass knots save 18% for malignancy;
Solid knots save 7% for malignancy;
Calcified nodules are almost 100% benign;
The probability of malignancy of mixed ground glass nodules is up to about 63%.
In terms of nodule size:
The probability of nodule cancer under 3 mm is only 0.2%;
The probability of malignancy < diameter of 6 mm is less than 1%;
The malignancy rate of 5-10 mm in diameter is 6%-28%;
The malignancy rate of > 20 mm in diameter is 64% to 82%.
In terms of the number of nodules: the probability of malignancy of single nodules is higher than that of multiple nodules.
Which groups and which nodules have a high probability of malignancy?
1. Long-term smoking history, family history of lung cancer, history of previous malignant tumors, long-term exposure to risk factors such as dust or chemical substances in the working environment, previous history of pulmonary interstitial fibrosis or COPD.
2. Nodules with tumor diameter ≥ 1.5 cm or diameter between 0.8-1.5 cm but showing malignant CT signs such as lobes, burrs, pleural traction, vascular puncture, bronchiollar and vacuole signs, eccentric thick-walled cavities.
3. Mixed ground glass nodules with a diameter greater than 0.8 cm.
4. Pure ground glass nodules that have not changed or gradually enlarged after anti-inflammatory treatment should be alert to adenomatous hyperplasia or carcinoma in situ. If there is a realistic component in the follow-up of pure ground glass nodules, it is necessary to be wary of the possibility of malignant nodules.
Therefore, the most important thing for lung nodules is to look at the diameter and change, the diameter is small, the density and morphology have not changed, it generally does not matter, the diameter of larger or gradually growing usually needs surgery, less than 3cm of the nodule even if it is malignant, most of it can still be surgically cured.
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