P21 is not a prognostic marker for rectal cancer - five-year follow up study of rectal cancer in stages I-IV

Five-year follow-up study of stage I-IV rectal cancer including EGFR immunoexpression and p21 immunoactivity

Introduction

Both environmental and genetic factors increase the likelihood of developing rectal cancer.

Aim

To assess the EGFR and p21 immunoreactivity in rectal cancer and to assess its relationship with the clinical outcome.

Material and methods

Applying exclusion criteria, 102 patients with stage I–IV rectal cancer, who had undergone scheduled surgery during the period 2005–2011, were included in the study. There was a follow-up study with a span of 5 years from the date of the surgery. Immunohistochemistry using epidermal growth factor receptor (EGFR Ab10, Clone111.6) and antibodies against p21 (p21^WAF1 (Clone H252)) was performed to detect overexpression of the targeted receptor. Digital analysis of positive reactions of membranes and nuclei was performed utilizing Visiopharm.

Results

The degree of EGFR intensity (log OR = 0.854, OR = 2.35, 95% CI: 1.14–4.85, p = 0.021) is a significant factor in the prognosis of death within 2 years after surgery. The OS curve showed a significant decrease after 40 months from the date of surgery in the cases where EGFR had high expression. The ROC curve for cancer stage, according to the UICC classification and EGFR expression, in order to predict 2-year RFS, reached a high specificity value (ROC = 0.81, p = 0.0408). The analysis showed no statistically significant differences in the survival curves of patients in groups with immunoreactivity of p21 protein at 0, 1, 2, 3 (p = 0.6453 in the log-rank test). Also, it is not a significant risk factor for death (HR = 0.915, p = 0.7842) or for tumor dissemination (HR = 0.94, p = 0.9426).

Conclusions

The determination of EGFR immunoreactivity is important in the monitoring and treatment of patients with rectal cancer, as opposed to p21.