Neoadjuvant Treatment Response As an Early Response Indicator for Patients With Rectal Cancer

Abstract

Treatment response to neoadjuvant chemoradiotherapy among patients with locally advanced rectal cancer undergoing radical resection is an early surrogate marker and correlate to oncologic outcomes. These data provide guidance with response-stratified oncologic benchmarks for comparisons of novel treatment strategies.

The current value of determining the mismatch repair status of colorectal cancer: A rationale for routine testing

“…With a reduced incidence of BRAF mutations one would expect dMMR rectal cancer to have an improved prognosis, however, initial prognostic studies were conflicting. One reported 5-year overall survival (OS) of 50% for 22 dMMR rectal cancers (Samowitz et al, 2009), and another reported 3-year disease free survival (DFS) of 90% for 20 dMMR rectal cancers (Hong et al, 2012), Nevertheless, in the largest, most recent clinical series dMMR rectal cancer was confirmed to have an outstanding prognosis compared with pMMR disease, with a 5-year OS and DFS of 90.6% (de Rosa et al, 2016) and 70% (Park et al, 2012) respectively for locally advanced rectal cancer and 5-year OS of 50% for metastatic CRC (Brouquet et al, 2010).…”

“…Early small series with little clinical detail and much heterogeneity reported rates of pathologic response between 0 and 60% (Bertolini et al, 2007;Cecchin et al, 2011;Charara et al, 2004;Lim et al, 2015;Shin et al, 2013). However, in the largest series to date pathologic response was found to be excellent, with a complete pathologic response (pCR) of 27.6% in locally advanced disease (de Rosa et al, 2016) compared to a pCR rate of 18% among patients without LS treated with neoadjuvant chemoradiation (Park et al, 2012). Importantly, dMMR rectal cancer's hypermutator phenotype, characterised by antigen formation and an enhanced immune response, may contribute to its favorable outcomes, highlighting the potential for emerging immunotherapeutic strategies .…”

The contribution of targeted therapy to the neoadjuvant chemoradiation of rectal cancer

“…An increasing number of studies performed with functional imaging techniques, including contrastenhanced dynamic MRI/computed tomography and 18F-fluorodeoxyglucose (18FDG) positron emission tomography in patients treated with standard CRT, shows the capability to obtain an early prediction of response by comparing basal versus intermediate evaluations of response to therapy [74][75][76][77][78][79][80][81].…”

Neoadjuvant Conformal Chemoradiation with Induction Chemotherapy for Rectal Adenocarcinoma. A Prospective Observational Study

“…Radiotherapy doses of 45 to 50 Gy with concomitant chemotherapy yield a clinical complete response (CCR) rate between 10.4% [3] and 27% [4]. e pathological complete response (PCR) can be higher, up to 35.1% [4][5][6][7]. Brachytherapy or orthovoltage boost approaches can yield a CCR of about 81% in selected patients [8,9].…”