The relationship of histological tumor regression grade (TRG) and two different time intervals to surgery following radiation therapy for locally advanced rectal cancer.
BACKGROUND
The objective of this study was to assess the effect of two different time intervals between radiation therapy and surgery for rectal cancer on the histological tumor regression grade (TRG) in the resected specimen.


METHODS
Between 1995 and 2000, patients undergoing preoperative radiation therapy and TME for locally advanced (T3N0 and T3N1) mid and low rectal tumors treated in the VU University Medical Center or the Zaans Medical Center were entered into this study. All patients received identical radiation treatment (5 x 5 Gy) in the VU University medical center and were subsequently operated on within 2 weeks in the Zaans Medical Center (SI group) and after 6-8 weeks in the VU University Medical Center (LI group). All available histological material was reevaluated for TRG and correlated to survival.


RESULTS
Sixty-seven patients were included in the present study, 28 in the LI group and 39 in the SI group. Patient gender was comparable for both groups with 21 (75%) male patients in the LI group versus 26 (67%) male patients in the SI group (p = 0.46). A T3N0 preoperative tumor stage was found in 21 (75%) patients in the LI group and in 33 (85%) patients in the SI group (p = 0.36). All tumors were histologically proven adenocarcinoma. Patients in the SI group were significantly older (67 vs. 58 years). In the LI group, a significantly more pronounced histological tumor regression was found. A complete response (TRG1), combined with a near complete histological response (TRG 2), were present in 12 patients in the LI group and in four patients in the SI group (p = 0.002). Radicality of resection was comparable for both groups. With a follow-up of over 60 months, there were no statistically significant differences between the SI and LI groups regarding local control, overall, or disease-free survival.


CONCLUSIONS
Although histological tumor regression is significantly more pronounced following a long interval between radiation therapy and surgery, in the present study, this is not reflected in a better radical resection rate, local control or better overall and disease-free survival.
Department of Surgery, VU University Medical Center, Postbus 7057, de Boelelaan 1117, 1007 MB Amsterdam, The Netherlands. a.veenhof@vumc.nl
A A F A
AA
Veenhof
E
E
Bloemena
A F
AF
Engel
D L
DL
van der Peet
O W M
OW
Meijer
M A
MA
Cuesta
D000230:Adenocarcinoma; D000367:Age Factors; D000368:Aged; D013505:Digestive System Surgical Procedures; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome