Chemotherapy stimulates cancer-associated fibroblasts to secrete interleukin-17A to provide maintenance cues to support the growth of colorectal cancer-initiating cells.

This is the first study to delineate American Joint Committee on Cancer/College of American Pathologists regression grade as an independent oncologic prognostic factor. This information can be used in discussions with patients who have rectal cancer.

The majority of patients attaining ypT0 status do not display mucosal features of complete response. When present, a mucosal complete response is statistically associated with ypT0 status, but is poorly sensitive. If rectal conservation after chemoradiation is to be pursued, alternative means of restaging are required to maximize the number who might benefit from this approach.

Statin therapy is associated with an improved response of rectal cancer to neoadjuvant chemoradiation. These data provide the foundation for a prospective clinical trial.

AJCC response score after nCRT is a novel prognostic factor in pathologic stage III rectal cancer and may guide surveillance and adjuvant therapy decisions.