Final answer:
Cancer staging involves classifying cancer according to tumor size, lymph node involvement, and the presence of metastasis, which helps in determining the prognosis and treatment strategy.
Step-by-step explanation:
The process of cancer staging is vital for classifying cancer based on factors like how large a tumor is and to what extent the cancer has spread. It is done to determine the prognosis and to establish the most effective treatment plan. For a 57-year-old woman diagnosed with infiltrating ductal carcinoma, staging would likely involve additional imaging such as MRI, CT scans, or bone scans, and possibly further biopsies to assess the extent of the cancer. There are various systems in place for cancer staging, but commonly, the TNM system is used, which considers the size of the tumor (T), whether the cancer has spread to the lymph nodes (N), and whether there is metastasis to distant organs (M).