Intensity-modulated Radiotherapy for Rectal Cancer in the UK in 2020

Mark Beavon ,Mark Harrison ,Rachel Adams ,M Hawkins ,C Arthur,A Duffton,Patrizia Pantano ,M Robinson,Ane L Appelt ,David Sebag‐Montefiore ,Alexandra Gilbert ,Séan M O’cathail ,Finbar Slevin ,Matthew Beasley ,Catherine Hanna ,Mark Teo ,S Teoh,Simon Gollins ,R Muirhead,Kirsten Laws

doi:10.1016/j.clon.2020.12.011

Abstract

AimsPreoperative (chemo)radiotherapy followed by total mesorectal excision is the current standard of care for patients with locally advanced rectal cancer. The use of intensity-modulated radiotherapy (IMRT) for rectal cancer is increasing in the UK. However, the extent of IMRT implementation and current practice was not previously known. A national survey was commissioned to investigate the landscape of IMRT use for rectal cancer and to inform the development of national rectal cancer IMRT guidance. Materials and methodsA web-based survey was developed by the National Rectal Cancer IMRT Guidance working group in collaboration with the Royal College of Radiologists and disseminated to all UK radiotherapy centres. The survey enquired about the implementation of IMRT with a focus on the following aspects of the workflow: dose fractionation schedules and use of a boost; pre-treatment preparation and simulation; target volume/organ at risk definition; treatment planning and treatment verification. A descriptive statistical analysis was carried out. ResultsIn total, 44 of 63 centres (70%) responded to the survey; 30/44 (68%) and 36/44 (82%) centres currently use IMRT to treat all patients and selected patients with rectal cancer, respectively. There was general agreement concerning several aspects of the IMRT workflow, including patient positioning, use of intravenous contrast and bladder protocols. Greater variation in practice was identified regarding rectal protocols; use of a boost to primary/nodal disease; target volume delineation; organ at risk delineation and dose constraints and treatment verification. Delineation of individual small bowel loops and daily volumetric treatment verification were considered potentially feasible by most centres. ConclusionThis survey identified that IMRT is already used to treat rectal cancer in many UK radiotherapy centres, but there is heterogeneity between centres in its implementation and practice. These results have been a valuable aid in framing the recommendations within the new National Rectal Cancer IMRT Guidance.

Highlights

In patients with locally advanced rectal cancer, radiotherapy has been shown to significantly reduce the risk of locoregional recurrence [1e6].Recently, preoperativeradiotherapy for rectal cancer has been increasingly delivered using intensitymodulated radiotherapy (IMRT)
Most respondents (36/44, 82%) indicated that they use IMRT to treat selected patients with rectal cancer and 68% (30/44) indicated that they use IMRT to treat all patients with rectal cancer
Recommendations concerning organ at risk (OAR) definition, treatment planning and image-guided radiotherapy were considered to be valuable. This survey has illustrated the current extent to which IMRT is used in the UK for rectal cancer treatment and the heterogeneity in its implementation and delivery

Summary

Introduction

In patients with locally advanced rectal cancer, radiotherapy has been shown to significantly reduce the risk of locoregional recurrence [1e6].Recently, preoperative (chemo)radiotherapy for rectal cancer has been increasingly delivered using intensitymodulated radiotherapy (IMRT). The extent of IMRT use in the UK for rectal cancer has been unclear and no consensus previously existed regarding its implementation. Given these uncertainties, the potential complexities of an IMRT workflow and the lack of a national strategy, a multidisciplinary working group was formed from radiotherapy centres across the UK to develop the National Rectal Cancer IMRT Guidance [7]. In order to inform guidance development and aid the framing of specific recommendations, the working group commissioned a national survey of radiotherapy centres. The objectives of the survey were to describe the current use and delivery of IMRT, to illustrate areas of consensus and heterogeneity in the IMRT pathway and to understand the feasibility of particular recommendations contained within the draft guidance document

Methods

Results

Conclusion