Prognostic importance of Mandard tumour regression grade following pre-operative chemo/radiotherapy for locally advanced rectal cancer.

Purpose: To assess the prognostic value of the Mandard tumour regression score (TRG) following pre-operative chemo/radiotherapy in patients with locally advanced rectal cancer.

Methods And Materials: The study involved 158 patients with locally advanced rectal cancer treated with pre-operative long course chemo/radiotherapy at Nottingham University Hospital between April 2001 and December 2008. Patients were treated with radiotherapy to a dose of 50 Gy in 25 fractions over 5 weeks with or without concurrent capecitabine chemotherapy at a dose of 1650 mg/m(2)/day. Surgery was normally performed after an interval of 6-10 weeks. The response to pre-operative treatment was carefully graded by a single pathologist using the five point Mandard score. The median follow-up was 40 months (range 3-90 months).

Results: Of the 158 patients 14% were TRG1, 41% were TRG2, 31% were TRG3, 13% were TRG4 and 1% were TRG5. The groups were combined into TRG1, TRG2 and TRG3-5 to simplify further analysis. The Mandard score was clearly related to both disease-free (p < 0.001) and overall survival (p = 0.012). On multivariate analysis perineural invasion, nodal status, TRG and circumferential resection margin status were the most powerful predictors of disease-free survival.

Conclusions: The Mandard tumour regression score is an independent prognostic factor and predicts for long-term outcome following pre-operative chemo/radiotherapy in rectal cancer.