In prostate cancer staging, the first echelon lymph node is?

In the context of prostate cancer staging, the first echelon lymph node refers to the first group of lymph nodes that drain lymphatic fluid from the prostate. The obturator lymph nodes are considered the first echelon node for prostate cancer because they are located in close proximity to the prostate and receive direct lymphatic drainage from it.

When cancer spreads, it typically does so through the lymphatic system to the nearest lymph nodes first, and in the case of prostate cancer, the obturator nodes are typically the initial site of metastasis. Recognizing these lymph nodes is paramount in both staging the disease and planning treatment approaches.

The other lymph nodes listed, including the external iliac, common iliac, and hypogastric nodes, while important in the overall lymphatic drainage of the pelvic region, are not the first encountered nodes in the drainage pathway from the prostate. Understanding this lymphatic pathway is crucial for clinicians when assessing cancer progression and determining appropriate intervention strategies.