1.Status of pediatric malignant solid tumors The spectrum of pediatric diseases in China has long undergone obvious changes, the incidence of infectious diseases and malnutrition has significantly decreased, and pediatric tumors have become the most important cause of death from diseases. According to statistics, there are about 26,000 cases of pediatric malignant tumors under 14 years old in China every year, and the incidence of pediatric tumors has increased at a rate of 5% every 5 years in recent years. 55%-60% of pediatric tumor patients are malignant tumors, and 70% of pediatric malignant tumors develop within 3 years old. The occurrence of pediatric malignant solid tumors is related to abnormal embryonic development, which can exist at birth, and some of them are malignant at birth, mainly embryonic tumors and sarcomas. Examples include malignant teratoma, neuroblastoma, nephroblastoma, hepatoblastoma, rhabdomyosarcoma, and retinoblastoma. These tumors are often associated with congenital malformations, such as nephroblastoma combined with unilateral limb hypertrophy, iris agenesis, and hypospadias. Some tumors are similar to adult tumors in that they begin as benign and later certain physical factors, chemical biological factors, chronic inflammation, immune deficiency, etc. may become predisposing factors for pediatric malignancy. Once the tumor deteriorates, the course of the disease progresses rapidly. The growth mode of pediatric malignant solid tumor is mainly expansive growth, the tumor expands and expands in multiple directions in a balanced manner, and as the tumor grows and expands, the tumor cells can form direct spread. Like adult tumors, pediatric tumors also metastasize distantly through blood and lymphatic system, and the metastasis appears early and progresses fast. The early symptoms of pediatric malignant tumor are mostly non-specific: low fever, anorexia, emaciation, weight loss, anemia, etc. Parents lack medical knowledge and vigilance, and primary care physicians lack corresponding knowledge and experience, so that the lumps are only discovered by chance when they grow rapidly, and most of them are diagnosed at late stage, which brings difficulties to treatment. (1) Unexplained bleeding, including bleeding gums, skin bleeding spots or petechiae; (2) Gradually worsening anemia and pallor not due to malnutrition or parasites; (3) Long-term unexplained fever, especially when antiviral or antimicrobial treatment is ineffective; (4) Longer persistent or intermittent pain (headache, abdominal pain, bone and (5) certain neurological symptoms, such as headache, vomiting, unsteady walking, facial nerve palsy, convulsions, etc.; (6) palpable masses, such as neck, axilla, groin, abdomen, posterior lumbar region, etc.; (7) enlarged liver and spleen; sudden enlargement of abdomen with pain, anemia; (8) visual impairment (squinting eyes, protruding eyes, etc.); (9) high or low white blood cells in routine blood tests or accompanied by red blood cells and thrombocytopenia, etc. The basic principle of treatment for pediatric malignant solid tumors is a comprehensive treatment that reflects individualized characteristics. In the past 20 years, pediatric tumor treatment has made remarkable progress, and the overall 5-year disease-free survival rate has reached about 70% on average, with the highest being 96%, except for very few diseases with less than 50%. The good treatment effect is attributed to the sound health network, good medical conditions, and innovative clinical treatment methods. The standardization and improvement of the level of comprehensive treatment ensure the improvement of clinical cure rate and survival quality. We recommend that pediatricians should have annual medical checkups and tumors should be included in the child health care routine.