The CARTS study: Chemoradiation therapy for rectal cancer in the distal rectum followed by organ-sparing transanal endoscopic microsurgery

Patients with a clinical T1-3 N0 M0 rectal adenocarcinoma below 10 cm from the anal verge will receive neoadjuvant chemoradiation therapy (25 fractions of 2 Gy with concurrent capecitabine). Transanal Endoscopic Microsurgery (TEM) will be performed 8 - 10 weeks after the end of the preoperative treatment depending on the clinical response.Primary objective is to determine the number of patients with a (near) complete pathological response after chemoradiation therapy and TEM. Secondary objectives are the local recurrence rate and quality of life after this combined therapeutic modality. A three-step analysis will be performed after 20, 33 and 55 patients to ensure the feasibility of this treatment protocol.The CARTS-study is one of the first prospective multicentre trials to investigate the role of a rectum saving treatment modality using chemoradiation therapy and local excision. The CARTS study is registered at clinicaltrials.gov (NCT01273051)Colorectal cancer is the third most common malignancy in the Netherlands with more than 10.000 new patients of whom approximately one third have rectal cancer.Total Mesorectal Excision (TME) using sharp nerve-sparing dissection, instead of blunt resection, reduced the 5-year local recurrence rate from up to 45% to less than 10% in patients with rectal cancer [1,2]. The use of this nerve-sparing technique results in lower rates of sexual dysfunction and urinary incontinence, but these complications are still common after TME [3]. Addition of preoperative radiotherapy to surgery resulted in a significant better local control for resectable rectal cancer. Five-year local control rate using a short course (5 × 5 Gy) of pre-operative radiotherapy was 6% compared to 11% after TME surgery alone [4]. Based on these results, standard treatment in the Netherlands for T2-3 rectal cancer without threatened circumferential margin (CRM) or N2 stage is pre-operative short course radiotherapy followed by TME surgery. Long course chemoradiati