Decreased tumor cell proliferation as an indicator of the effect of preoperative radiotherapy of rectal cancer.
BACKGROUND
Rectal cancer is a common malignancy, with significant local recurrence and death rates. Preoperative radiotherapy and refined surgical technique can improve local control rates and disease-free survival.


OBJECTIVE
To investigate the relationship between the tumor growth fraction in rectal cancer measured with Ki-67 and the outcome, with and without short-term preoperative radiotherapy.


METHODS
Ki-67 (MIB-1) immunohistochemistry was used to measure tumor cell proliferation in the preoperative biopsy and the surgical specimen.


METHODS
Specimens from 152 patients from the Southeast Swedish Health Care region were included in the Swedish rectal cancer trial 1987-1990.


RESULTS
Tumors with low proliferation treated with preoperative radiotherapy had a significantly reduced recurrence rate. The influence on death from rectal cancer was shown only in the univariate analysis. Preoperative radiotherapy of tumors with high proliferation did not significantly improve local control and disease-free survival. The interaction between Ki-67 status and the benefit of radiotherapy was significant for the reduced recurrence rate (p = 0.03), with a trend toward improved disease-free survival (p = 0.08). In the surgery-alone group, Ki-67 staining did not significantly correlate with local recurrence or survival rates.


CONCLUSIONS
Many Ki-67 stained tumor cells in the preoperative biopsy predicts an increased treatment failure rate after preoperative radiotherapy of rectal cancer.
Adell
G
G
Division of Oncology, Department of Biomedicine and Surgery, University Hospital, Linköping, Sweden. Gunnar.Adell@lio.se
Zhang
H
H
Jansson
A
A
Sun
X F
XF
Stål
O
O
Nordenskjöld
B
B
D000230:Adenocarcinoma / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002455:Cell Division / Q000528:radiation effects; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D009367:Neoplasm Staging; D011300:Preoperative Care; D012004:Rectal Neoplasms / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D016896:Treatment Outcome
D019394:Ki-67 Antigen