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.

No abstract

High-resolution magnetic resonance (MR) imaging plays a pivotal role in the pretreatment assessment of primary rectal cancer. The success of this technique depends on obtaining good-quality high-resolution T2-weighted images of the primary tumor; the mesorectal fascia, peritoneal reflection, and other pelvic viscera; and superior rectal and pelvic sidewall lymph nodes. Although orthogonal axial high-resolution T2-weighted MR images are the cornerstone for the staging of primary rectal cancer, high-resolution sagittal and coronal images provide additional value, particularly in tumors that arise in a redundant tortuous rectum. Coronal high-resolution T2-weighted MR images also improve the assessment of nodal morphology, particularly for superior rectal and pelvic sidewall nodes, and of the relationship between advanced-stage tumors and adjacent pelvic structures. Rectal gel should be used in MR imaging examinations conducted for the staging of polypoid tumors, previously treated lesions, and small rectal tumors. However, it should not be used in examinations performed to stage large or low rectal tumors. Diffusion-weighted imaging is useful for identifying nodes and, occasionally, the primary tumor when the tumor is difficult to visualize with other sequences. Three-dimensional T2-weighted imaging provides multiplanar capability with a superior signal-to-noise ratio compared with two-dimensional T2-weighted imaging.

Preoperative NLR influenced the disease-free survival in patients with stages I to III CRC. Elevated NLR (>3) was associated with worse outcome (5-year disease-free survival 66.3  % vs. 78.9  % in colon cancer, P < 0.001; 60. 5 % vs. 66.2  % in rectal cancer, P = 0.008). The difference was larger in colon cancer than in rectal cancer. NLR should be considered as a prognostic factor for stages I to III CRC patients after curative surgery.

An elevated NLR is an independent predictor of OS but not DFS in stage II colon cancer patients who did not receive adjuvant chemotherapy. Preoperative NLR measurement in stage II colon cancer patients may be a simple method for identifying patients with a poor prognosis who can be enrolled in further trials of adjuvant chemotherapy.