Screening Methods Population Selection for Screening: Utilizing a cluster sampling approach, one-fifth of the residents from six townships/districts were selected as the target population. Villages (communities) were organized and mobilized as units to central screening points. Work personnel were assigned to collaborate with local health institutions (community health service centers) to conduct a comprehensive survey of residents within their jurisdiction. The target population was registered and documented, and informed consent forms were obtained during this process.

Assessment of High-Risk Population: Utilizing a combination of questionnaire surveys and biological testing, the target population underwent risk assessment to identify individuals at high risk requiring clinical screening. Personnel administered the 'Cancer Risk Assessment Questionnaire (2022 edition)' and the 'Traditional Chinese Medicine Spleen Deficiency Questionnaire (TCM-SDQ)' to residents for a comprehensive assessment of multi-cancer disease risk. The questionnaire survey was conducted through face-to-face interviews by surveyors, with data entered into the 'Lanxi Multi-Cancer Joint Screening' data management platform. Ensuring residents fully understood the questionnaire content, maintaining the confidentiality of the survey, and ensuring the authenticity of the information were essential during the investigation. Additionally, on-site testing for Hepatitis B surface antigen (HBsAg), fecal occult blood test (FIT), and Helicobacter pylori (Hp) was carried out. Whole blood, feces, urine, and other samples were collected on the same day for biological testing.

Clinical Screening: For individuals identified as high-risk for cancer by the risk assessment system, they were informed of their cancer risk and organized to undergo specified clinical screenings at designated hospitals. The clinical screenings included low-dose CT (LDCT) for the lungs, upper gastrointestinal endoscopy with targeted indicated pathological biopsy, colonoscopy with targeted indicated pathological biopsy, AFP detection and liver ultrasound, molybdenum target, and ultrasound, among others. The screening protocols for the five common cancers (lung, upper gastrointestinal, colorectal, liver) followed the 'Urban Cancer Screening and Early Diagnosis and Treatment Project Technical Plan (2022 edition).' Results from clinical screenings were systematically recorded in the 'Lanxi City Multicancer Integrated Screening' data management platform.

Population Follow-up: For individuals identified as high-risk in the past and requiring follow-up, notifications were sent through the information platform. Project unit staff, following the screening tasks, collected information on the diagnosis and treatment of the follow-up subjects. Follow-up activities were conducted actively and passively, employing methods such as direct face-to-face visits, telephone interviews, self-administered questionnaires, regular physical examinations, environmental and disease monitoring, and collection of attendance records from hospitals and workplaces. The active follow-up targeted individuals with positive findings of various cancers detected through clinical examinations in the past (specific criteria outlined in the 'Urban Cancer Screening Early Diagnosis and Treatment Project Follow-up Plan'). Active follow-up involved undergoing clinical examinations again and collecting follow-up information. Among them, those undergoing clinical examinations were included in the annual completion volume. Follow-up information included detailed information on diagnosis and treatment. For de-ceased individuals, specific death information (including time and cause of death, etc.) needed to be obtained. Passive follow-up involved matching the project participants with the local cancer registry and cause-of-death monitoring database to supplement information on cancer incidence and death among project participants.