12th May 2024

A 52-year-old woman presents with post-coital bleeding, vaginal discharge, and lower back pain.

A 52-year-old woman presents with post-coital bleeding, vaginal discharge, and lower back pain. She reports a history of multiple sexual partners and infrequent use of barrier contraception. A cervical biopsy reveals squamous cell carcinoma. Subsequent imaging demonstrates involvement of the parametrial tissue but no distant metastasis.

Which is the most likely mechanism for the local spread of this tumour to the parametrial tissue?