Abstract 868
Background
NCCN guidelines recommend local excision (LE) as a standard treatment for selected patients with cT1/T2,N0,M0 rectal cancer. However, the rates of local recurrence after LE alone were 12.5% in cT1 disease and 22.1% in cT2 disease and those after total mesorectal excision (TME) were 6.9% and 15.1%, respectively. In pathological T1 disease, adding (chemo)radiotherapy (CRT) to LE decreased the rate of local recurrence to 5%, which was comparable to the rate after TME (4%). In pT2 disease who underwent LE, the local recurrence rate decreased slightly but remained high (14%) even after CRT.
Methods
In our institution, patients with cT1, N0 disease with a tumor diameter of less than 30 mm underwent transanal full thickness LE and additionally receive CRT (40/45Gy plus UFT or S-1). Patients with poorly differentiated adenocarcinoma or mucinous carcinoma should additionally undergo TME. Patients with cT2, N0 disease underwent transanal LE after CRT. Patients whose tumors include poorly differentiated adenocarcinoma or mucinous carcinoma should receive TME.
Results
In accordance with these treatment policy, LE was performed in 65 patients with cT1, N0 disease, 50 of whom additionally received CRT. The median follow-up was 71 months. Local recurrence occurred in 1 patient (2%), and distant metastasis occurred in 3 patients (6%). The 5-year disease-free survival rate (5y DFS) was 86%, and the 5-year overall survival rate (5y OS) was 92%. Patients with pT1 disease who had local nodal recurrence underwent abdominoperineal resection and are still alive with no recurrence. In 53 patients with cT2, N0 disease, LE was performed after CRT. Four patients had pT3 disease and additionally underwent TME. In the other 49 patients, six patients (12%) had local recurrence at the anastomotic site, and 7 (14%) had distant metastasis. The 5y DFS was 70%, and the 5y OS was 87%.
Conclusions
These results suggested that multidisciplinary treatment combining chemoradiotherapy with local excision is a treatment option in some patients with a preoperative diagnosis of clinical T1, N0 or T2, N0 rectal cancer. However, further studies are needed to determine the optimal treatment for patients with clinical T2, N0 rectal cancer.
Clinical trial identification
Legal entity responsible for the study
Sotaro Sadahiro.
Funding
Has not received any funding.
Editorial Acknowledgement
Disclosure
All authors have declared no conflicts of interest.
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