Left rib pain is not always an early sign of cancer. Left rib pain may be caused by a variety of diseases, such as fracture, costochondritis, fasciitis, pleurisy, shingles, herniated disc, osteophyte, gastroesophageal reflux, pneumothorax, and angina, and is not necessarily an early sign of cancer. However, bone metastasis occurs in the advanced stage of lung cancer, for example, tumor cells metastasize to the ribs, which may cause left rib pain. Therefore, left rib pain does not completely exclude the possibility of cancer, and it is recommended to go to regular hospitals as soon as possible to improve relevant examinations, such as chest radiographs, CT, etc., to clarify the specific triggering causes. If it is a disease factor or a manifestation of advanced lung cancer, one should cooperate with professional doctors to carry out standardized treatment in time to control the condition as early as possible and avoid further development.