Pathological grading of regression: an International Study Group perspective

In this issue of the Journal of Clinical Pathology , MacGregor, Maughan and Sharma1 discuss the value and utility of pathological grading of regression from an oncologist's point of view. Neoadjuvant chemoradiotherapy is now a well-accepted treatment for locally advanced rectal cancer (cT3/T4 or lymph node-positive rectal cancers). However, neoadjuvant therapy affects the histopathological reporting of resected specimens by virtue of the host response to treatment, which occurs in the majority of patients. Pathological complete responses ranging from 9% to 29% have been reported,2 ,3 but the clinical significance of ‘incomplete’ regression and, more importantly, its role in determining postoperative treatment, is not clear. Pathological complete response has been associated with good patient outcomes.4–7 However, tumour regression grade (although having prognostic value for survival and recurrence by univariate analyses) has not been established to be an independent prognostic value that is superior to ypTNM in predicting clinical outcome.6 ,7–13 On the contrary, Min et al 11 demonstrated that regression grading is a good prognostic factor in patients with lymph node negative locally advanced rectal cancer. Therefore, regression grading may be a useful parameter for monitoring patient response and also as a potential prognostic factor. Several grading systems have been proposed and used, the most popular one being the Mandard and Dworak systems.14 ,15. We, an ‘International …