12th May 2024

A 68-year-old man presents with difficulty urinating, nocturia, and a dull pain in the pelvic area.

A 68-year-old man presents with difficulty urinating, nocturia, and a dull pain in the pelvic area. He has a history of elevated prostate-specific antigen (PSA) levels. A digital rectal examination reveals a hard, nodular prostate. A biopsy confirms adenocarcinoma of the prostate. Bone scan shows increased uptake in the lumbar spine and pelvis.

Which is the most likely route by which this tumour spread to the lumbar spine?