Introduction: Colorectal cancer is a major cause of morbidity and mortality throughout the world. The widespread implementation of neoadjuvant radiotherapy and chemotherapy (CRT) has reduced local recurrence rates from 25% to 40% to less than 10%. However, many patients undergo radiotherapy and chemotherapy for resistant cancers, thus incurring side-effects without benefit. Expression of particular genes at molecular level can be related to response or resistance to systemic therapies. In this study we have assessed the predictive value of VEGF, EGFR and p53 in predicting the response to neoadjuvant CRT in locally advanced rectal cancers. Material and Methods: Patients with locally advanced carcinoma rectum (stage II and III) were included in the study. Following completion of neoadjuvant CRT patients were evaluated to assess the response of CRT. The response of CRT was assessed using RECIST criteria. The response to CRT was correlated with the level of molecular markers. Results: Total 35 patients were included in the study. Over expression of VEGF, EGFR and p53 was associated with poor response to neo-adjuvant chemo-radiotherapy. The findings were statistically significant in case of VEGF and EGFR. Conclusion: We conclude that molecular markers (VEGF, EGFR and p53) may become tools for selection of patients suitable for chemoradiation in carcinoma rectum. However, more studies are needed with larger sample size and longer follow up for establishing molecular markers as predictors of  response to chemoradiation and overall outcome in patients of carcinoma rectum.

Keywords: Rectal Carcinoma; Neoadjuvant Chemoradiotherapy.