This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Ca prostate commonly metastasises to the veebrae: 
Select and explain. 
A. Because valveless communication exist with Batson's periprostatic plexus., B. Via drainage to Sacral lymph node, C. Of direct Spread, D. None of the above
A: Because valveless communication exist with Batson's periprostatic plexus.
Answer: A: Because valveless communication exist with Batson's periprostatic plexus. 
Explanation: Prostate cancer homing to the lumbar spine mediated by the connection of the Batson's periprostatic venous vessel to the veebral venous plexus. Ref: The Biology of Skeletal Metastases: Volume 118, 2004, Page 292; bailey and Love's Sho Practice of Surgery, 23rd Edition, Page 1250; Clinical Surgery By S. Das, Page 196.