How does staging differ from grading in tumor pathology?

Staging and grading are two fundamental concepts in tumor pathology that serve different purposes in assessing cancer. Staging primarily focuses on the extent of disease, specifically assessing tumor size, local invasion, and the presence of metastasis to lymph nodes or distant sites. This helps in determining how advanced the cancer is and guides treatment options as well as prognosis.

In contrast, grading evaluates the cellular features of the tumor, particularly how the cancer cells look under a microscope compared to normal cells. It assesses factors such as the degree of differentiation and the overall appearance of the cells, which can indicate how aggressive the tumor may be.

The distinction between staging and grading is critical for proper clinical management of cancer because while staging informs us about the extent of spread, grading gives insight into the biological behavior of the tumor. Therefore, stating that staging assesses tumor size and spread while grading focuses on cell appearance encapsulates the core difference between the two concepts.