Background: Preoperative radiochemotherapy (RCT) is recommended in France prior to total mesorectal excision in patients with mid or low locally advanced rectal cancer (LARC) (cT3/T4 and/or N+) because it has been shown to improve local control. Preoperative RCT has also disadvantages including the absence of proven impact on metastatic recurrence and the risk of late side effects on bowel and genitourinary function. In patients with primarily resectable LARC, preoperative systemic chemotherapy without pelvic irradiation could be used as an alternative to RCT.
Methods: This study is a multicenter, open-label randomized, 2-arm phase III non-inferiority trial. Patients with mid or low resectable LARC (cT3N0 or cT1-T3N+ with circumferential resection margin [CRM] > 2 mm on pretreatment MRI) will be randomized to either modified FOLFIRINOX for 3 months or RCT (Cap50 intensified-modulated radiotherapy). All patients have restaging MRI after preoperative treatment. The primary endpoint is 3-year progression-free survival (PFS) from the time to randomization including progression during preoperative treatment. Secondary endpoints are treatment related toxicity, treatment compliance, R0 resection rate, sphincter saving surgery rate, postoperative morbidity and mortality rates, loco-regional recurrence free survival, overall survival, bowel and sexual functions at diagnosis, quality of life, radiologic and pathologic response after preoperative treatment. The number of patients required is 574.
Discussion: The choice of modified FOLFIRINOX for preoperative chemotherapy is supported by recent and consistent data on safety and efficacy of this regimen on rectal cancer. The use of preoperative chemotherapy instead of RCT could be associated with pronounced advantages in terms of functional results and quality of life in cancer survivors. However and first of all, the non-inferiority of preoperative chemotherapy compared to RCT on oncologic outcome has to be validated. If this study demonstrates the non-inferiority of chemotherapy compared to RCT, this can lead to a crucial change in clinical practice in a large subset of rectal cancer patients.
Trial registration: ClinicalTrials.gov NCT03875781 (March 15, 2019). Version 1.1.
Keywords: Circumferential resection margin; Functional result; Locally advanced rectal cancer; Preoperative chemotherapy; Preoperative radiochemotherapy; Quality of life.