A patient is diagnosed with cancer. Size of the lesion is found to be 5 cm in diameter and metastasis is found with single ipsilateral lymph node. The stage according to TNM staging is:
**Core Concept**
The TNM staging system is a widely used classification system for cancers, which takes into account the size and extent of the primary tumor (T), the degree of lymph node involvement (N), and the presence of metastasis (M). The correct staging of a cancer is crucial for determining the prognosis and guiding treatment.
**Why the Correct Answer is Right**
In the TNM staging system, the T category is determined by the size of the primary tumor. A tumor size of 5 cm or more in greatest dimension corresponds to T3. The N category is determined by the number of involved lymph nodes. A single ipsilateral lymph node corresponds to N1. Since there is no mention of distant metastasis (M), it is assumed to be M0. Therefore, the correct staging is T3N1M0.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the T category based on the tumor size.
**Option B:** This option is incorrect because it does not match the N category based on the number of involved lymph nodes.
**Option C:** This option is incorrect because it implies the presence of distant metastasis (M1), which is not mentioned in the question.
**Clinical Pearl / High-Yield Fact**
When using the TNM staging system, it's essential to remember that the T category is determined by the size of the primary tumor, the N category by the number of involved lymph nodes, and the M category by the presence of distant metastasis.
**Correct Answer:** C. T3N1M0