P53 adapted neoadjuvant therapy for esophageal cancer: Pilot study

Abstract

4535 Background: Randomized trials could not yet prove clinical efficacy of neoadjuvant chemotherapy for esophageal cancer. A survival benefit could be shown for treatment responders only. Using platinum based regimen, yet about 20 % of patients can achieve pathological complete remission which translates in reported 3-year survival rates of 64% in this group. Factors identifying this subgroup of responders and selecting optimal drugs for non responders could dramatically enhance treatment efficacy. Several studies suggest that mutations in the p53 gene may induce drug resistance especially for agents whose effect is based on apoptosis induction, like Cisplatin. Methods: In order to test the hypothesis that the p53 genotype is predictive for chemotherapy response, a prospective study was conducted. Thirty-eight patients with potentially respectable esophageal cancer were evaluated for the relation between p53 genotype and response to two different neoadjuvant treatments. P53 gene mutations were assessed by complete direct sequencing of DNA extracted from diagnostic biopsies. Response to neoadjuvant chemotherapy was assessed pathohistologically in the surgical specimen. Results: 20 squamous cell carcinoma and 18 adenocarcinoma were included. Overall the p53 mutation rate was 58% (22/38), with 66 % for squamous cell and 53% for adenocarcinomas, respectively. 30 patients received CIS/5FU (cisplatin 80mg/m2 d1 5-FU 1,000mg/m2 d 1–5, q21,2 cycles), 8 received docetaxel (75mg/m2, q21,2 cycles). The overall response rate was 48% (18/38). Patients with p53 mutation did not respond to CIS/5-FU (0/16), while all mutant patients responded to docetaxel (6/6). The overall response to p53 adapted neoadjuvant therapy was 94%. P53 adapted treatment was associated with a significant survival advantage (p=0,042) after a median follow up of 15,4 months. Conclusions: A prospective randomized trial was initiated to test the interaction between the predictive marker p53 and response to CIS/5-FU and Docetaxel, respectively. [Table: see text] No significant financial relationships to disclose.