Developing guidelines for the diagnosis and treatment of common cancers in China based on the evidence-based practice, the availability of diagnosis and treatment products, and the up-to-date advances in precision medicine is one of the basic tasks of the Chinese Society of Clinical Oncology (CSCO). In recent years, the availability of medical resources has become a major concern in clinical guidelines, which is particularly important for developing countries or socioeconomically diverse countries and territories. China is the world's largest developing country, with a large territory and uneven economic and academic developments. The CSCO guidelines must take into account the differences in regional development, the availability of medicines and diagnostic methods, and the social value of cancer treatment. Therefore, for each clinical problem and intervention in the CSCO guidelines, the levels of evidence should be graded according to the currently available evidences and expert consensuses, and the grades of recommendations should be based on the availability and cost- effectiveness of the products. Protocols with high evidence level and good availability are used as the Level I recommendations; protocols with relatively high evidence level but slightly lower expert consensus or with poor availability are used as the Level II recommendations; and protocols that are clinically applicable but with low evidence level are regarded as the Level III recommendations. Based on the findings of clinical research at home and abroad and the opinions of CSCO experts, the CSCO guidelines determine the levels of recommendations for clinical application. The CSCO Guidance Working Group firmly believes that evidence-based, availability-concerned, and consensus-based guidelines will be more feasible for clinical practice. Again, any comments from our readers are greatly appreciated and will be considered in updates of these guidelines, so as to maintain the accuracy, fairness, and timeliness of the CSCO guidelines.