New aspects for staging and grading of tumor metastases

Modern therapeutic regimens have improved the prognosis of patients with metastatic tumours. This requires a subclassification of metastases with more categories than M0 versus M1/pM1. For some tumour entities UICC proposals exist for a subclassification of metastases: colorectal cancer, lung cancer, malignant bone tumours, malignant melanoma and Merkel cell carcinomas of skin, as well as uterine and prostate cancer. Metastases are graded according to the same principles as the corresponding primary tumours. Differences in the grade between primary tumour and metastases have been described without evident differences in prognosis. Recent reports showed a similar prognosis for colorectal carcinoma liver metastasis resected R0 or R1. In a certain percentage of R1 resections an inconsistent use of the R classification as to R1 may be responsible.