Epidermal growth factor receptor as a predictor of tumor downstaging in locally advanced rectal cancer patients treated with preoperative chemoradiotherapy

Methylation of p16 and p14 genes is a common event in colorectal cancers; however, their exact role in the prediction of patients? outcome is unclear. We conducted this retrospective study to evaluate their potential predictive and/or prognostic roles. Methylation-specific PCR was used to examine the methylation status of p16 and p14 in pretherapeutic and preoperative biopsy specimens of 60 patients with locally advanced rectal cancer. The methylation status of the examined genes did not affect the response to preoperative chemoradiotherapy (CRT), recurrence rate and overall survival. However, patients with a simultaneous presence of either p16 or p14 methylation and high vascular endothelial growth factor (VEGF) expression showed a significantly worse response to CRT (p=0.005 and p=0.038, respectively). Moreover, patients with both p16 methylation and high VEGF expression had significantly shorter overall survival (p=0.010), while no such association was found in patients with p14 methylation and high VEGF expression. On the other hand, a subgroup of patients with p16 methylation and low VEGF and high epidermal growth factor receptor (EGFR) expression showed a significantly better response to CRT (p=0.024). The obtained results point to the importance of p16 and p14 methylation analyses in combination with VEGF and EGFR expression, aimed at better predicting treatment response and patient outcome.

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Treatment related changes of the serum epidermal growth factor receptor in advanced colorectal cancer

Journal of Clinical Oncology ◽

10.1200/jco.2009.27.15_suppl.e22096 ◽

2009 ◽

Vol 27 (15_suppl) ◽

pp. e22096-e22096

Author(s):

K. G. Spindler ◽

D. Olsen ◽

I. Brandslund ◽

A. Jakobsen

Keyword(s):

Colorectal Cancer ◽

Rectal Cancer ◽

Epidermal Growth Factor Receptor ◽

Growth Factor ◽

Prognostic Value ◽

Locally Advanced ◽

Growth Factor Receptor ◽

Skin Toxicity ◽

Epidermal Growth ◽

Pre Treatment

e22096 Background: The epidermal growth factor receptor (EGFR) is an established target for therapy in colorectal cancer. The extracellular domain of the receptor is shed into circulation and detectable by ELISA. We investigated the changes in sEGFR levels during preoperative chemoradiation (CRT) in rectal cancer patients and third-line treatment with cetuximab and irinotecan (CETIRI) in advanced disease, to elucidate the predictive or prognostic value in these settings. Methods: We included 126 healthy controls and 118 patients with chemorefractory mCRC treated with cetuximab (initial 400/m2 mg followed by weekly 250mg/m2) and irinotecan (350 mg/m2 q3w). Response was evaluated according to RECIST. Furthermore, 114 patients with locally advanced rectal tumours were treated with CRT (60 Gy/30 fractions and concomitant uftoral (300 mg/m2)/leukovorin (22.5 mg) on treatment days, followed by surgery 8 weeks post-treatment and pathological tumour regression evaluation. Pre-treatment and consecutive samples were drawn at each visit. sEGFR was measured by ELISA. Median statistics and Kaplain-Mayer curves with log-rank testing for comparison of survival rates were performed. Results: There were significant differences between the median pre-treatment sEGFR levels in controls, rectal cancer and mCRC (58 ng/ml(56–59 95% C-I), 53 ng/ml(51–55 95% C-I) and 51 ng/ml(49–53 95% C-I), respectively, p<0.000). We detected a rapid increase in sEGFR by the first on- treatment values during CETIRI (p<0.001), and a correlation between the magnitude of increase and a higher degree of skin toxicity, a well known indicator of clinical benefit to EGFR inhibitors. sEGFR in rectal cancer patients displayed a decreasing tendency during CRT (p<0.001), but no correlation to local tumour response. Patients with baseline pre-treatment level > 43.4 ng/ml (mean sEGFR of control group-2xSD) had a significantly higher OS rate than patients with low baseline levels (93% and 59% respectively, HR 0.15, P=0.002). Conclusions: We report a rapid increase in sEGFR by the onset of CETIRI, which may indicate development of skin toxicity and thereby a better change of response. Furthermore, we suggest a potential prognostic value of sEGFR measurement during CRT in locally advanced rectal cancer. No significant financial relationships to disclose.

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