Neoadjuvant radiotherapy for rectal cancer management

Abstract

Thirty per cent of all colorectal tumours develop in the rectum. The location of the rectum within the bony pelvis and its proximity to vital structures presents significant therapeutic challenges when considering neoadjuvant options and surgical interventions. Most patients with early rectal cancer can be adequately managed by surgery alone. However, a significant proportion of patients with rectal cancer present with locally advanced disease and will potentially benefit from down staging prior to surgery. Neoadjuvant therapy involves a variety of options including radiotherapy, chemotherapy used alone or in combination. Neoadjuvant radiotherapy in rectal cancer has been shown to be effective in reducing tumour burden in advance of curative surgery. The gold standard surgical rectal cancer management aims to achieve surgical removal of the tumour and all draining lymph nodes, within an intact mesorectal package, in order to minimise local recurrence. It is critically important that all rectal cancer cases are discussed at a multidisciplinary meeting represented by all relevant specialties. Pre-operative staging including CT thorax, abdomen, pelvis to assess for distal disease and magnetic resonance imaging to assess local involvement is essential. Staging radiology and MDT discussion are integral in identifying patients who require neoadjuvant radiotherapy. While Neoadjuvant radiotherapy is potentially beneficial it may also result in morbidity and thus should be reserved for those patients who are at a high risk of local failure, which includes patients with nodal involvement, extramural venous invasion and threatened circumferential margin. The aim of this review is to discuss the role of neoadjuvant radiotherapy in the management of rectal cancer.

Keywords: Rectal cancer; Neoadjuvant therapy; Low anterior resection syndrome; Stoma; Transanal endoscopic microsurgery; Trans-anal total mesorectal excision; Robotic surgery; Watch and wait

Core tip: Neoadjuvant radiotherapy aims to downstage tumours for a more effective oncological resection. Studies have shown that both long and short course pre-operative radiotherapy confers benefits to local recurrence. Some patients completely respond to radiotherapy and have been enrolled in surveillance programmes without undergoing surgery. It is essential to be aware of the disadvantages associated with radiotherapy. Radiation therapy increases the risk of anorectal and genitourinary dysfunction which have a deleterious impact on quality of life. Thus it is imperative to accurately identify patients who are likely to benefit from neoadjuvant radiotherapy in order to minimise morbidity and improve patient outcomes.