Distal intramural spread of rectal cancer after preoperative radiotherapy: the results of a multicenter randomized clinical study.
OBJECTIVE
To evaluate the extent of distal intramural spread (DIS) after preoperative radiotherapy for rectal cancer.


METHODS
A total of 316 patients with T(3-4) primary resectable rectal cancer were randomized to receive either preoperative 5x5 Gy radiation with immediate surgery or chemoradiation (50.4 Gy, 1.8 Gy per fraction plus boluses of 5-fluorouracil and leucovorin) with delayed surgery. The slides of the 106 patients who received short-course radiation and of the 86 who received chemoradiation were available for central microscopic evaluation of DIS.


RESULTS
The length of DIS did not differ significantly (p = 0.64) between the short-course group and the chemoradiation group and was 0 in 47% vs. 49%; 1 to 5 mm in 41% vs. 42%; 6 to 10 mm in 8% vs. 9%, and greater than 10 mm in 4% vs. 0, respectively. Among the 11 clinically complete responders, DIS was found 1 to 5 mm from the microscopically detected ulceration of the mucosa in 5 patients. The discontinuous DIS was more frequent in the chemoradiation group as compared with the short-course group (i.e., 57% vs. 16% of cases, p < 0.001).


CONCLUSIONS
Approximately 1 out of 10 advanced rectal cancers after preoperative radiotherapy or radiochemotherapy was characterized by DIS of over 5 mm. No significant difference was seen in the length of DIS between the 2 groups.
Chmielik
Ewa
E
Department of Pathology, Maria Sklodowska-Curie Memorial Cancer Center, Gliwice, Poland.
Bujko
Krzysztof
K
Nasierowska-Guttmejer
Anna
A
Nowacki
Marek P
MP
Kepka
Lucyna
L
Sopylo
Rafal
R
Wojnar
Andrzej
A
Majewski
Przemyslaw
P
Sygut
Jacek
J
Karmolinski
Andrzej
A
Huzarski
Tomasz
T
Wandzel
Piotr
P
D000328:Adult; D000368:Aged; D001003:Anal Canal; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D018709:Statistics, Nonparametric
D000964:Antimetabolites, Antineoplastic; D002955:Leucovorin; D005472:Fluorouracil