Updates in the Eighth Edition of the Tumor-Node-Metastasis Staging Classification for Urologic Cancers

The Tumor-Node-Metastasis (TNM) classification on cancer staging, jointly developed by the American Joint Commission on Cancer (AJCC) and the Union for International Cancer Control (UICC), has been updated to its 8th edition with two contemporaneous versions published by the AJCC and UICC. While the goal of the AJCC and UICC is to have identical TNM staging systems, differences exist between these two publications including in the staging of urologic cancers. Among several new facets in the AJCC staging manual, a select few of greater import include an expanded section on imaging, presentation of levels of evidence for significant changes, and endorsement of risk assessment models that pass the AJCC quality criteria such as in prostate cancer. The updates for urologic cancers in the AJCC stage categories can be grouped into: (1) newly defined TNM categories and prognostic stage groupings, (2) clarifications and refinements of previously defined categories, and (3) more systematic and expanded presentation of prognostic factors. Changes are harmonized with the current reporting and treatment guidelines. Contributions from genitourinary pathology are evident in the AJCC classification from many of the International Society of Urological Pathology (ISUP) consensus conferences on prostate, kidney, testicular, and penile neoplasms that addressed staging issues and the timely publication of the 4th edition of the World Health Organization (WHO) classification of urinary and male genital organ tumors. New grading approaches for penile (WHO/ISUP grade), prostate (Grade group), and kidney (WHO/ISUP nucleolar grade) cancers were adopted in the AJCC system. Many of these updates in the AJCC staging manual are also included in the 8th UICC TNM edition. In an effort to achieve the optimal staging recommendations for urologic cancers, updates in the 8th TNM edition were generated through the acquisition of best evidences, tapping interdisciplinary resources including consensus recommendations, and enhanced data analysis. Patient summary: In this report, we explain the seminal changes in the 8th edition of the Tumor-Node-Metastasis staging system for urologic cancers. Major stage category definitional changes are in Tumor-Node-Metastasis classifications of testicular, penile, and prostate cancer which improve patient stratification for prognosis and management. Refining the standards that provide the best possible staging system is a never-ending process. The 8th edition continues in that tradition with a more focused attempt to incorporate nonanatomic factors into staging. This approach is most evident in staging of prostate cancers where nonanatomic factors including grade of tumor and serum prostate specific antigen levels significantly impact American Joint Committee on Cancer prognostic stage group assignment whereby which even some organ-confined cancers may be classified as stage III cancer.