Pathological response following long-course neoadjuvant chemoradiotherapy for locally advanced rectal cancer.
OBJECTIVE
To standardize the pathological analysis of total mesorectal excision specimens of rectal cancer following neoadjuvant chemoradiotherapy for locally advanced disease (T3/T4), including tumour regression.


RESULTS
Standardized dissection and reporting was used for 60 patients who underwent total mesorectal excision following long-course chemoradiotherapy. Tumour regression was scored by two pathologists (K.S., D.G.) using both an established 5-point tumour regression grade (TRG), and a novel 3-point grade. Both scores were evaluated for interobserver variability. A complete or near-complete pathological response (3-point TRG 1) was found in 10 patients (17%). Using the 5-point TRG, there was good agreement between both pathologists (kappa = 0.64). Using the 3-point grade, agreement was excellent (kappa = 0.84). No disease recurrence has been reported in patients with a complete, or near complete pathological response (3-point TRG 1), after a mean follow-up of 22 months.


CONCLUSIONS
Tumour regression grade is a useful method of scoring tumour response to chemoradiotherapy in rectal cancer. TRG 1 and 2 can be regarded as a complete pathological response (ypT0). A modified 3-point grade has the advantage of better reproducibility, with similar prognostic significance.
Ryan
R
R
Centre for Colorectal Disease, St Vincent's University Hospital, Dublin, Ireland.
Gibbons
D
D
Hyland
J M P
JM
Treanor
D
D
White
A
A
Mulcahy
H E
HE
O'Donoghue
D P
DP
Moriarty
M
M
Fennelly
D
D
Sheahan
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging / Q000379:methods*; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D015203:Reproducibility of Results; D016896:Treatment Outcome