Accuracy of MRI in early rectal cancer: national cohort study

Radiological staging of rectal cancer dictates subsequent patient
treatment. In early-stage disease, local excision is associated
with reduced morbidity, mortality, and costs, and maintains
bowel continuity compared with surgery, where the whole or
part of the rectum is resected1–3
. Nearly 90 per cent of patients
with T1 rectal cancer have N0 disease and are therefore potentially curable with local resection, yet the majority undergo major resection4–6
. MRI is the primary staging investigation used to predict
local stage in rectal cancer7, mainly owing to its ability to allocate
patients in need of neoadjuvant treatment8–10. There is potentially inaccuracy in MRI staging for nodal involvement and differentiation of T1 from T2 tumours6,7,11. Consequently, cT1 and cT2 are
often combined and comprice tumours considered for local resection. Apart from a recent study6 reporting 54 per cent accuracy for
MRI cT1–2 category, combined cT1–2 status has not been
investigated.
The aim of this large nationwide retrospective cohort study was
to investigate the staging accuracy of MRI, from a clinical perspective, in early rectal cancer when combining cT1 and cT2 categories.