Neoadjuvant Pelvic Radiotherapy in the Management of Rectal Cancer with Synchronous Liver Metastases: Is it Worth it?

Abstract

Introduction: The use of neoadjuvant pelvic radiotherapy was a major advance in oncologic care for locally-advanced rectal cancer (RC) in the 20th century. The extrapolation of the care of locally-advanced RC to the management of RC with treatable liver metastases is controversial. The aim of this systematic review is to examine the available data on the role of pelvic radiotherapy and chemoradiation in the setting of treatable metastatic liver disease. Methods: A systematic review of MEDLINE was performed to report the landmark randomized controlled trials between 1993-2021. Results: Attaining liver clearance and total mesorectal excision with negative margin remains the mainstay of cure. There is uncertainty regarding the sequencing of treatment. The literature lacks randomized clinical trials comparing the rectal first, liver first, interval strategy and simultaneous surgical approaches. A multidisciplinary discussion regarding the utility of radiotherapy is emphasized to achieve the goals of treatment. Short-course radiotherapy has proved comparable disease-control outcomes to long-course chemoradiation with a significantly improved cost-performance. The implementation of short-course radiotherapy in the interval strategy and simultaneous surgical approach is promising. Neoadjuvant pelvic radiotherapy can be omitted in patients with metastatic RC if adequate margin clearance is achievable. Conclusion: The use of pelvic radiotherapy in metastatic RC is popular, but can be omitted when R0 resection can be achieved. Treatment should be tailored to the local extent of RC and priority of liver metastasis management. The optimal treatment strategy in patients with synchronous rectal liver metastases needs to be studied in randomized trials.