Epidermal growth factor receptor as a predictor of tumor downstaging in locally advanced rectal cancer patients treated with preoperative chemoradiotherapy.
OBJECTIVE
To examine retrospectively whether levels of epidermal growth factor receptor (EGFR) expression can predict tumor downstaging after preoperative chemoradiotherapy in patients with locally advanced rectal cancer.


METHODS
A total of 183 patients with rectal cancer (cT3-T4 or N+) were enrolled in this study. Preoperative chemoradiotherapy consisted of 50.4 Gy of pelvic radiation with concurrent 5-fluorouracil and leucovorin bolus intravenous chemotherapy in 94 patients or oral capecitabine and leucovorin in 89 patients. EGFR expression in pretreatment paraffin-embedded tumor biopsy specimens was assessed by immunohistochemistry. EGFR expression was determined from the intensity and extent of staining. Tumor downstaging was defined as a reduction of at least one T-stage level.


RESULTS
Tumor downstaging occurred in 97 patients (53%), and the tumors showed a pathologic complete response in 27 patients (15%). Positive EGFR expression was observed in 140 (76%) of 183 patients. EGFR expression levels were low in 113 patients (62%) and high in 70 patients (38%). On logistic regression analysis, the significant predictive factor for increased tumor downstaging was a low level of EGFR expression and preoperative chemotherapy using oral capecitabine (odds ratio, 0.437; p = 0.012 vs. odds ratio, 3.235; p < 0.001, respectively).


CONCLUSIONS
A high level of EGFR expression may be a significant predictive molecular marker for decreased tumor downstaging after preoperative chemoradiotherapy in locally advanced rectal cancer.
Kim
Jun-Sang
JS
Department of Radiation Oncology, Chungnam National University College of Medicine, Daejeon, Republic of Korea. k423j@cnu.ac.kr
Kim
Jin-Man
JM
Li
Shengjin
S
Yoon
Wan-Hee
WH
Song
Kyu-Sang
KS
Kim
Ki-Hwan
KH
Yeo
Seung-Gu
SG
Nam
Ji Sook
JS
Cho
Moon-June
MJ
D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism*; D000069287:Capecitabine; D003131:Combined Modality Therapy / Q000379:methods; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D002955:Leucovorin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology* / Q000532:radiotherapy; D012189:Retrospective Studies
D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D003841:Deoxycytidine; D000069287:Capecitabine; D066246:ErbB Receptors; D002955:Leucovorin; D005472:Fluorouracil