Professional and Linguistic Assessments Board (PLAB) Practice Exam

According to Dukes staging, which stage is classified as confined to the mucosa?

1. A

2. B

3. C

4. D

The correct answer is: A

In Dukes staging, Stage A is classified as the stage where cancer is confined to the mucosa of the bowel. This means that the malignant cells are present solely within the epithelial layer and have not invaded deeper structures or spread to nearby lymph nodes or distant sites. Stage A represents an early stage of colorectal cancer, indicating a better prognosis for patients, as treatment at this stage often involves surgical resection with a high likelihood of a successful outcome. The other stages in the Dukes classification indicate increasing levels of depth of invasion and potential spread. Stage B generally involves invasion beyond the mucosa into the muscularis propria but still does not show lymphatic involvement. Stage C indicates that cancer has spread to nearby lymph nodes, and Stage D encompasses metastatic disease, where the cancer has spread to distant organs. Understanding these distinctions aids in determining the appropriate treatment strategy and estimating the prognosis for the patient.