| Abstract |
BACKGROUND: Tailored neoadjuvant treatment of locally advanced rectal cancer (LARC) may improve outcomes. The aim of this study was to determine early MRI prognostic parameters with which to stratify neoadjuvant treatment in patients with LARC.
METHODS: All patients from a prospective, phase II, multicentre randomized study (GRECCAR4; NCT01333709) were included, and underwent rectal MRI before treatment, 4?weeks after induction chemotherapy and after completion of chemoradiotherapy (CRT). Tumour volumetry, MRI tumour regression grade (mrTRG), T and N categories, circumferential resection margin (CRM) status and extramural vascular invasion identified by MRI (mrEMVI) were evaluated.
RESULTS: A total of 133 randomized patients were analysed. Median follow-up was 41ˇ4 (95 per cent c.i. 36ˇ6 to 45ˇ2) months. Thirty-one patients (23ˇ3 per cent) developed tumour recurrence. In univariable analysis, mrEMVI at baseline was the only prognostic factor associated with poorer outcome (P?= 0ˇ015). After induction chemotherapy, a larger tumour volume on MRI (P?= 0ˇ019), tumour volume regression of 60 per cent or less (P?= 0ˇ002), involvement of the CRM (P?= 0ˇ037), mrEMVI (P?= 0ˇ026) and a poor mrTRG (P?= 0ˇ023) were associated with poor outcome. After completion of CRT, the absence of complete response on MRI (P?= 0ˇ004), mrEMVI (P?= 0ˇ038) and a poor mrTRG (P?= 0ˇ005) were associated with shorter disease-free survival. A final multivariable model including all significant variables (baseline, after induction, after CRT) revealed that Eastern Cooperative Oncology Group performance status (P?= 0ˇ011), sphincter involvement (P?= 0ˇ009), mrEMVI at baseline (P?= 0ˇ002) and early tumour volume regression of 60 per cent or less after induction (P?= 0ˇ007) were associated with relapse.
CONCLUSION: Baseline and early post-treatment MRI parameters are associated with prognosis in LARC. Future preoperative treatment should stratify treatment according to baseline mrEMVI status and early tumour volume regression. |
Institut de Recherche en Cancérologie de
