Adjuvant therapy sparing in rectal cancer achieving complete response after chemoradiation

Abstract

Aim: To evaluate the long-term results of conventional chemoradiotherapy and laparoscopic mesorectal excision in rectal adenocarcinoma patients without adjuvant therapy.

Methods: Patients with biopsy-proven adenocarcinoma of the rectum staged cT3-T4 by endoscopic ultrasound or magnetic resonance imaging received neoadjuvant continuous infusion of 5-fluorouracil for five weeks and concomitant radiotherapy. Laparoscopic surgery was planned after 5-8 wk. Patients diagnosed with ypT0N0 stage cancer were not treated with adjuvant therapy according to the protocol. Patients with ypT1-2N0 or ypT3-4 or N+ were offered 5-fluorouracil-based adjuvant treatment on an individual basis. An external cohort was used as a reference for the findings.

Results: One hundred and seventy six patients were treated with induction chemoradiotherapy and 170 underwent total mesorectal excision. Cancer staging of ypT0N0 was achieved in 26/170 (15.3%) patients. After a median follow-up of 58.3 mo, patients with ypT0N0 had five-year disease-free and overall survival rates of 96% (95%CI: 77-99) and 100%, respectively. We provide evidence about the natural history of patients with localized rectal cancer achieving a complete response after preoperative chemoradiation. The inherent good prognosis of these patients will have implications for clinical trial design and care of patients.

Conclusion: Withholding adjuvant chemotherapy after complete response following standard neoadjuvant chemoradiotherapy and laparoscopic mesorectal excision might be safe within an experienced multidisciplinary team.

Trial registration: ClinicalTrials.gov NCT01500993.

Keywords: Exercise; Follow-up; Gastrointestinal diseases; Irritable bowel syndrome; Physical activity.

Figures

Figure 1

Patient flow chart of the main cohort. CRT: Chemoradiotherapy; CT: Chemotherapy; PE: Pulmonary embolism; RT: Radiotherapy; TEM: Transanal endoscopic microsurgery.

Figure 2

Cumulative hazards estimates. A: Local relapse in the main cohort; B: Distant relapse in the main cohort; C: Local relapse in the external reference cohort (note: complete- and intermediate-responders overlap); D: Distant relapse in the external reference cohort.

Figure 3

Kaplan-Meier estimates. A: Disease-free survival in the main cohort; B: Overall survival in the main cohort; C: Disease-free survival in the external reference cohort; D: Overall survival in the external reference cohort.