Incidence of Metachronous Distant Metastasis and ypN Classification Influence Patient Survival in Endosonographically Confirmed uT3 Rectal Cancer after Neoadjuvant Therapy and R0 Resection: A Historical Cohort Analysis

Background: Tumor response after neoadjuvant radiochemotherapy (NRC) prior to surgery and other parameters are likely to have an influence on the survival rate of patients suffering from T3 rectal cancer.

Methods: 51 patients (17 female, 34 male; 59.0 years; Apache < 9 points: 95.1%; ASA I-II 88.3% and ASA III 11.8%) were treated with NRC (50.4 Gy; 5-fluorouracil/folinic acid) 4-6 weeks prior to surgery because of uT3 rectal cancer (G2: 96%; adenocarcinoma 86.3%; cUICC II 62.7%). NRC led to a tumor response (TR) (ypT0-ypT2) in 45.1% (ypT0N0M0 7.8%).

Results: Neither the age of patients nor Apache/ASA score, histology, UICC staging, ypTNM, Dukes staging, infiltration of vessels, surgical procedure, local recurrence nor TR had a significant influence on the patients' survival time. Patients with metachronous distant metastasis (MDM) during the follow-up period (mean: 8.2 years; 1 month to 14.5 years) and patients with ypN1-ypN2 had a significantly shorter survival time.

Conclusions: NRC prior to surgery leads to a remarkable TR rate but has no significant impact of TR on the patients' survival time. Occurrence of MDM during the follow-up period and ypN1/N2 status do have a greater influence. It is necessary to investigate larger cohorts of patients in the future to obtain more conclusive results and to define factors with influence on survival.