Lung Cancer Screening and Early Diagnosis/Treatment Protocol (2024 Edition)

Lung cancer is the most common cancer in China and a serious threat to residents' health. Studies show that low-dose computed tomography (LDCT) screening of high-risk populations can effectively improve early diagnosis and reduce mortality. To further standardize lung cancer screening and early diagnosis/treatment and improve prevention outcomes, this technical protocol is issued.

I. Epidemiology

Surveillance data show that in 2022 China had 1.0606 million new lung cancer cases, 22.0% of all malignant tumors; and 733,300 lung cancer deaths, 28.5% of all malignant tumor deaths. The incidence and mortality were 75.13/100,000 and 51.94/100,000, respectively, overall on the rise. Lung cancer has a poor prognosis; although 5-year survival has improved in recent years it remains low. Early detection and treatment can markedly improve 5-year survival.

Major risk factors include tobacco exposure, air pollution, occupational exposure (asbestos, radon, beryllium, chromium, cadmium, nickel, silica, soot and coal smoke), COPD, and family history of lung cancer in first-degree relatives.

II. High-Risk Population

Age ≥50 years and meeting any one of the following:

(1) Smoking pack-years ≥20, including former smokers with ≥20 pack-years who quit less than 15 years ago. Note: pack-years = packs per day (20 cigarettes per pack) × years smoked.

(2) Living or working in the same room with smokers for ≥20 years.

(3) Having chronic obstructive pulmonary disease.

(4) Occupational exposure history (asbestos, radon, beryllium, chromium, cadmium, nickel, silica, soot, coal smoke) for at least 1 year.

(5) A first-degree relative (parent, child, or sibling) diagnosed with lung cancer.

III. Screening

(1) Target population

High-risk populations without prior lung cancer history, generally aged 50-74.

(2) Screening method

LDCT is recommended. A 16-slice or greater multi-detector spiral CT is suggested. CT reading and diagnosis must be performed by at least 2 physicians with ≥2 years of imaging diagnosis experience. LDCT parameters and workflow are given in the appendix.

Chest X-ray, MRI, PET-CT, and biomarker testing are not recommended for lung cancer screening.

(3) Screening outcomes

By thin-section CT density, non-calcified nodules detected are classified as solid, part-solid, and non-solid (pure ground-glass density). Solid nodules completely obscure lung parenchyma; part-solid nodules obscure part of the parenchyma; non-solid nodules do not obscure parenchyma, with recognizable bronchi and vessels.

(4) Screening frequency

High-risk individuals should in principle undergo LDCT annually. Shorten the interval if any of the following:

1. Detected solid nodule, or solid component of a part-solid nodule, with mean diameter ≥6 mm and <15 mm; or non-solid nodule mean diameter ≥8 mm and <15 mm: repeat at 3 months, then decide the next interval by results.

2. Detected solid nodule, solid component of part-solid nodule, or non-solid nodule with mean diameter ≥15 mm: if malignancy cannot be excluded, repeat 1-3 months after standard anti-inflammatory therapy, then decide by results.

IV. Principles of Early Diagnosis and Treatment

Lung cancer should be diagnosed early and treated promptly with standardized care. Early diagnosis relies mainly on imaging, with pathology when necessary. Clinical staging should include (cervical) chest/abdominal (pelvic) contrast CT, bronchoscopy, MRI, PET-CT, and ultrasound. Staging follows the UICC TNM system (8th edition); histologic typing follows WHO 2021 lung cancer classification.

(1) Non-small cell lung cancer (NSCLC)

1. Stages I and II.

Radical surgery is preferred; postoperative adjuvant therapy (chemotherapy, targeted therapy, etc.) is decided by pathological stage. If surgery is infeasible or refused, chemotherapy, immunotherapy, targeted therapy, radiotherapy, or local ablation may be considered.

2. Stage III.

Divided into resectable and unresectable NSCLC. Resectable stage III uses surgery-based multimodal treatment. Unresectable or inoperable stage III uses radical concurrent chemoradiotherapy. See the latest National Health Commission lung cancer guidelines.

3. Stage IV.

Choose systemic therapy based on confirmed histology (squamous vs. non-squamous) and driver-gene mutation status.

(2) Small cell lung cancer (SCLC)

Divided into limited and extensive stages. Limited-stage SCLC may consider combined chemotherapy, radiotherapy, and surgery. Extensive-stage SCLC may choose chemotherapy, radiotherapy, immunotherapy, or palliative care.

V. Follow-up and Management

In principle, all screenees should be followed at least once a year to obtain final diagnosis and outcome. Negative screenees receive health education about their risk factors and are reminded to screen on schedule; screen-positive individuals are treated and followed per clinical standards.

Appendix: LDCT Parameter Settings and Workflow

1. Spiral scan mode; pitch ≤1; gantry rotation time ≤0.8 s; total whole-chest dose ≤2 mSv.

2. Use the device's shortest scan time. Scan matrix ≥512×512; without iterative reconstruction, use 120 kVp and 30-50 mAs; with newer iterative reconstruction, use 100-120 kVp and <30 mAs.

3. Reconstruct with lung and standard algorithms, or standard alone, with slice thickness 1.00-1.25 mm. If slice thickness ≤0.625 mm, recommend no gap; if 1.00-1.25 mm, reconstruction interval ≤80% of slice thickness.

4. Enable the "dose report" function during scanning.

5. Patient supine, arms raised, single breath-hold at end-inspiration.

6. Scan range from lung apex to the level of the posterior costophrenic angle tip (including both lungs and chest walls; for female subjects, include both breasts).