"Since the publication of the 8th edition of the UICC TNM Classification of Malignant Tumours, continued advances in medicine have resulted in a need to update some of the chapters. In addition, there have been updates in affiliated organizations' staging systems such as AJCC, FIGO and IASLSC that require changes to be made to ensure compatibility and agreement in staging globally. It is also proposed to introduce some new tumour entities and anatomic sites (CNS, Cutaneous Lymphoma, Paraganglioma and Parathyroid Tumours). Revisions follow the basic philosophy of maintaining stability of the classification over time. Some of the tumour sites such as oesophagus, stomach and liver and genitourinary malignancies are unchanged from the eighth edition. The modifications and additions reflect new data on prognosis as well as new methods for assessing prognosis"--