Defining early recurrence of locally recurrent rectal cancer

Despite advances in rectal cancer treatments, its local recurrence rate is still 4-10 percent. And an evidence-based definition of early recurrence is lacking. Our study hopes to establish a clear threshold to distinguish early and late recurrence, and analyze risk and prognostic factors for them. Rectal cancer patients who underwent proctectomy from 2009 to 2019 were included. Patients who received neoadjuvant treatment and with incomplete records were excluded. The optimal interval was obtained using the minimum P value approach. Risk factors for early recurrence were analyzed by logistic regression models, and prognostic factors associated with additional surgery were assessed by Cox proportional hazards models. The optimal interval for the definition of early recurrence was 26 months based on the subsequent prognosis (P < 0.001). The 5-year survival rate of early and late recurrence cohort was 32.5% and 57.1%, respectively (P < 0.001). Adjuvant radiotherapy was the independent protective factor for early recurrence. And the presence of lymphovascular invasion, positive surgical margin, and no re-neoadjuvant radiotherapy were independent prognostic factors for the survival of LRRC patients under additional surgery.