ESTRO 2024 - Abstract Book

S1552

Clinical - Lower GI

ESTRO 2024

In recent years, therapeutic options in the management of rectal cancer have expanded the use of less aggressive surgical techniques, including local excision, instead of most standard radical surgery based on TME (total mesorectal excision) with anterior rectal resection (RAR) or abdominoperineal amputation (AAP).

Although RAR and AAP are among the main surgical modalities in the treatment of these tumours, both are associated with significant morbidity, which may limit the treatment of certain patients.

Recently, local excision has been established in selected cases as an alternative to radical surgery in early stages. Technical developments have made it possible to achieve better local excision techniques, such as TEM (transanal endoscopic microsurgery), TAMIS (minimally invasive transanal surgery) or TEO (transanal endoscopic operation). These techniques could imply a higher risk of local recurrence due to the unknown status of the lymph nodes. However, adjuvant treatment with radiotherapy or chemoradiotherapy (RT/QRT) can reduce this risk by sterilising the surgical bed and the mesorectum.

Hypothesis:

Local excision followed by adjuvant chemoradiotherapy or radiotherapy in early-stage rectal cancer may be an alternative for radical surgery based on AAP/RAR with TME in selected patients.

Objectives:

- To evaluate overall survival (OS), disease-free survival (DFS), local relapse-free survival (LRFS), nodal relapse-free survival (NRFS) and distant metastasis-free survival (DMFS) in patients treated with TAMIS and adjuvant radiotherapy versus radical surgery.

- Evaluation of prognostic factors and toxicity of both treatments.

Material/Methods:

In this retrospective study, we analyzed 58 patients with an anatomopathological diagnosis of rectal adenocarcinoma, clinical stage cT1-2cN0M0, treated at our institution between 2004 and 2022.

There were 37 males (64%) and 21 females (36%). The mean age at diagnosis was 67 years (39-88).

The clinical stage of our patients was cT1: 27 patients (47%), cT2: 31 patients (53%).

Twenty-three patients were treated with local resection and adjuvant pelvic irradiation (TAMIS-RT/RTQT) +/- boost to the surgical anastomosis, total mean dose: 50.7 Gy (45-61.20). Eighteen patients (78%) received concurrent capecitabine (825 mg/m2/12h/28 days).

Thirty-five patients were treated with radical surgery based on RAR and TME in 33 patients (57%) and APP with TME in 2 patients (3.4%). There were no differences in patients demographic characteristics between both groups.

Statistics: Student's t-test, chi-squared and Kaplan-Meier.

Results:

Median follow-up was 73 months (3-232).