598P - Influence of the early stoma closure after low rectal cancer resection on completeness of adjuvant chemotherapy (CoCStom): A randomized, controlled multicentre trial of the AIO (AIO KRK 0113)

Background

There is uncertainty whether early closure (EC) of a defunctioning stoma influences the complete administration of the adjuvant chemotherapy (CoC) after low anterior rectal resection (LAR) for rectal cancer. CoC was previously shown in retrospective analyses to improve the five-year OS and DFS.

Methods

CoCStom trial was a prospective randomized multicenter investigator-initiated study. Patients undergoing neoadjuvant therapy (chemoradiation or 5x5 Gy radiotherapy) followed by LAR for locally advanced rectal cancer were randomized in two arms. Experimental - EC, 8 to 10 days after LAR; and control - late closure of the stoma (LC), after completion of the adjuvant chemotherapy (26 weeks) which included both 5-FU- and oxaliplatin-based regimens according to local practice and tumor stage. The primary endpoint was CoC. The study was designed to show an CoC improvement of 20 % (power 80%, alpha-value 0.05). Secondary endpoints: oncological and surgical outcomes as well as quality of life.

Results

A total of 257 patients with comparable baseline characteristics and pathohistological (UICC) stages were randomized between 2013 and 2018. Of these, 233 (EC: 116 vs. LC: 117) were eligible for analysis. Median follow up was 24 months. Surgical morbidity after stoma closure was comparable (Clavien Dindo III-IV: EC vs. LC: 15.8 vs. 18.9%). The median hospitalization after LAR was 17 days in both groups. CoC was similar EC [62.9% (95% CI: 53.5 - 71.7%] and LC [65.8% (56.5 -74.3%]. Patients in the EC group started adjuvant chemotherapy (median 38 vs. 27 days after randomization) significantly later and received less oxaliplatin-based regimens (8.5 vs. 15%). DFS was numerically better in the EC group (HR 1.6; 95% CI: 0.83 – 3.06).

Conclusions

EC of the stoma was feasible and did not lead to increased surgical morbidity. CoC was not improved, however, a trend towards better DFS was observed within the EC group despite similar CoC, a later start of adjuvant therapy as well as less use of oxaliplatin-based regimens. Thus, EC of the stoma appears to be a valid option for patients undergoing LAR.

Clinical trial identification

DRKS00005113.

Editorial acknowledgement

Legal entity responsible for the study

Flavius Sandra-Petrescu, MD, on behalf of the CoCStom Study Group.

Funding

German Research Foundation (DFG) - KI1315/2-1 and SA 3642/1-2.

Disclosure

All authors have declared no conflicts of interest.