The role of MRI in the indication of the neoadjuvant chemo-radiotherapy for rectal cancer

Background: According to the current guidelines of rectal cancer treatment neoadjuvant radio- and/or chemotherapy is recommended if the staging confirms at least a T3 or N positive category. At the same time on the basis of more studies it is possible to perform a primary R0 resection if the perirectal fascia is not infiltrated. The omission of neoadjuvant treatment also reduces complications. The studies also debate whether the lymph nodes suspected to be positive with imaging, will be proven to be metastatic histologically. The effect of the neoadjuvant treatment on the metastatic lymphnodes is also questioned. According to the newest ESMO guideline T3 subgroups exist which can also influence treatment. Our aim was to examine whether an R0 resection is possible in patients with perirectal fat infiltration but without perirectal fascia involvement described by MRI. We compared the value of CT and MRI imaging regarding local propagation. We also investigated whether lymph nodes suspected to be positive by the imaging are really metastatic histologically.