MRI­based neoadjuvant therapy indication in middle and low rectal cancer.

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate the indication of neoadjuvant therapy in patients with middle and low rectal cancer based on MRI examination. BACKGROUND: In spite of noticeable advances in the diagnosis of rectal cancer, the optimal treatment remains highly debated. Current guidelines advise the use of neoadjuvant therapy in UICC stage II patients or higher. However, in clinical praxis, there is gradual implementation of new criterions and variables used in rectal cancer stage evaluation, the fact of which influences the treatment choice. The most important emerging variables taken currently into account are the distance from mesorectal fascia, circumferential resection margin, extramural venous invasion and intersphincteric plane, all of which can be evaluated using the MRI examination. METHODS: The accuracy of MRI staging was compared with definite histopathological results from resected tumors. Patient data were prospectively collected between the years 2013 and 2018 at 3rd Surgical Clinic, Faculty of Medicine, Comenius University in Bratislava, Slovakia. Data from 101 patients were gathered and divided into two groups, according to the localization of tumor within rectum, while 9 patients were excluded from the study because of benign lesion diagnosis based upon final histopathologic evaluation. RESULTS: In 92 evaluated patients, no significant change was noted between MRI and histopathological T-staging. However, in N-staging, significant differences were noted between preoperative MRI staging and postoperative histopathological staging. CONCLUSION: The results of this study demonstrate inefficient preoperative lymph node staging, suggesting overtreatment of rectal cancer patients. Although the use of neoadjuvant therapy has led to great advances in modern cancer treatment, it is connected with a number of side effects and therefore should be indicated only for patients who can benefit from this treatment (Tab. 1, Fig. 3, Ref. 16).