Preoperative management of locally advanced rectal cancer and the role of restaging MRI: An australasian perspective

Abstract

Background: Major advances in the management of locally advanced rectal cancer has led to controversies and varying clinical practices among colorectal surgeons, such as patient selection for neoadjuvant therapy and preferred regimen for neoadjuvant therapy. In addition, the role of restaging scans post-neoadjuvant therapy is still poorly established. Objectives: To examine current practice in the preoperative management of locally advanced rectal cancer in Australasia and determine the value of restaging magnetic resonance imaging (MRI). Design: Cross-sectional study (survey). Setting: Specialist colorectal surgeons in Australia and New Zealand. Participants and Methods: A web-based survey was distributed to the Colorectal Surgical Society of Australia and New Zealand (CSSANZ) members between December 2016 and February 2017. Information on demographics, imaging modalities used for staging, indications and choice of neoadjuvant therapy, as well as utility and perceived value of restaging MRI after neoadjuvant therapy was collected. Respondents were given hypothetical scenarios to assess their management decisions based on the findings of restaging MRI scans. Sample Size: 225. Main Outcome Measures: Preferred imaging modalities for staging and restaging of rectal cancer post-neoadjuvant therapy; indications and preferred regimen for neoadjuvant therapy; and utility and perceived value of restaging scans, particularly MRI, Results: Sixty-two (27.6%) CSSANZ members responded. Main neoadjuvant therapy indications included advanced T3 tumors (80.7% for T3c; 83.9% for T3d), T4 tumors (87.1%), nodal metastases (69.4% for N1; 77.4% for N2), and an involved circumferential resection margin (CRM) (95.2%). Long-course chemoradiotherapy was preferred for neoadjuvant therapy (80.6%). The preferred initial-stage imaging modalities were MRI (100%) and computed tomography of chest, abdomen, and pelvis (CT-CAP) (100%). Fifty-six (90.3%) respondents would perform restaging scans post neoadjuvant therapy in selected patients. An involved CRM was frequently identified as a feature on restaging MRI which may affect management (78.6%), with extramural venous invasion (EMVI) (7.1%) or tumor regression grading (TRG) (26.8%) rated less significant. Conclusion: Preoperative management of locally advanced rectal cancer in Australasia is generally consistent with current guidelines. Restaging MRI after neoadjuvant therapy undoubtedly has a role for guiding patient management, but larger prospective studies are warranted to firmly establish their place in daily clinical practice. Limitations: Poor response rate, leading to a small sample size; study population limited to colorectal surgeons in Australasia; and difficult to assess how restaging scans may change management plan. Conflict of Interest: None.