The Value of Restaging With Chest and Abdominal CT/MRI Scan After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

Abstract

Little was known with regard to the value of preoperative systemic restaging for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). This study was designed to evaluate the role of chest and abdominal computed tomography (CT) scan or magnetic resonance imaging (MRI) on preoperative restaging in LARC after neoadjuvant CRT and to assess the impact on treatment strategy.Between January 2007 and April 2013, 386 newly diagnosed consecutive patients with LARC who underwent neoadjuvant CRT and received restaging with chest and abdominal CT/MRI scan were included. Imaging results before and after CRT were analyzed.Twelve patients (3.1%) (6 liver lesions, 2 peritoneal lesions, 2 distant lymph node lesions, 1 lung lesions, 1 liver and lung lesions) were diagnosed as suspicious metastases on the restaging scan after radiotherapy. Seven patients (1.8%) were confirmed as metastases by pathology or long-term follow-up. The treatment strategy was changed in 5 of the 12 patients as a result of restaging CT/MRI findings. Another 10 patients (2.6%) who present with normal restaging imaging findings were diagnosed as metastases intra-operatively. The sensitivity, specificity accuracy, negative predictive value, and positive predictive values of restaging CT/MRI was 41.4%, 98.6%, 58.3%, and 97.3%, respectively.The low incidence of metastases and minimal consequences for the treatment plan question the clinical value of routine restaging of chest and abdomen after neoadjuvant CRT. Based on this study, a routine restaging CT/MRI of chest and abdomen in patients with rectal cancer after neoadjuvant CRT is not advocated, carcino-embryonic antigen (CEA) -guided CT/MRI restaging might be an alternative.

What Is the Utility of Restaging Imaging for Patients With Clinical Stage II/III Rectal Cancer After Completion of Neoadjuvant Chemoradiation and Prior to Proctectomy?

“…For instance, in a multi-institutional retrospective study from 5 centers, Hanley et al reported newly detected distant metastases in 18/267 (6.7%) of patients using CT CAP. 7 In 2 other single-institution studies, Davids et al 8 and Liu et al 9 found new metastatic disease in 5% and 3.1%, respectively. Moreover, in the study by Liu et al, cost-benefit analysis of restaging imaging did not have a favorable cost-benefit ratio.…”

“…Moreover, in the study by Liu et al, costbenefit analysis of restaging imaging did not have a favorable cost-benefit ratio. 9 Finally, Jaffe et al found that among 76 patients with no metastatic disease on initial clinical staging, preoperative reimaging did not detect disease progression in any patients. 10 Alternatively, others have reported higher rates of detecting disease progression following completion of neoadjuvant chemo/XRT.…”

“…Only the study by Liu et al evaluated carcinoembryonic antigen (CEA) levels before and after neoadjuvant chemo/XRT and found that an increase in CEA was more sensitive but less specific than CT and MRI in detecting disease progression. 9 However, not all tumors produce CEA and therefore utilization of this tumor marker to determine who should or should not have preoperative restaging is of limited value. Moving forward, molecular profiling of the primary tumor 16 as well as evaluation for circulating cancer cells, 17 may be beneficial in predicting patients at high risk for early systemic progression.…”

Ability of Delta Radiomics to Predict a Complete Pathological Response in Patients with Loco-Regional Rectal Cancer Addressed to Neoadjuvant Chemo-Radiation and Surgery

“…Several works in the last few decades suggest the feasibility of a wait-and-see approach in patients with very high surgical risk or trans-anal rectal excision approach if a significant response to CRT is assessed [ 1 , 10 , 12 , 13 ]. In this regard, magnetic Resonance Imaging (MRI) seems to be helpful to provide morphological and functional pieces of information that can be used to predict prognosis in pre-treatment patients [ 14 , 15 , 16 , 17 , 18 , 19 ], but its value in the pre- and post-CRT response assessment is still debated [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ].…”