Both primary and restaging MRIs can help define the risk of lateral local recurrence and the need for lateral lymph node dissection after chemoradiotherapy or radiotherapy in patients with low rectal cancer, according to a multinational study.

In the Dutch-led study, carried out at 12 centres in seven countries, data on 741 patients with low rectal cancer were reviewed.

While most patients (651) had undergone chemoradiotherapy or radiotherapy with total mesorectal excision for stage cT3 or cT4 low rectal cancer, 90 also underwent lateral lymph node dissection.

The aim of the study was to see whether the appearance of lymph nodes on MRI imaging — whether primary or restaging — could predict which patients were likely to have local recurrence.