Can we Save the rectum by watchful waiting or transanal surgery following short- or long-course radioTherapy and Additional local oR systemic Treatment for early-stage REctal Cancer?

Prior treatment

• Tumour located in the proximal rectum for which PME-surgery will be sufficient
• Any form of (endoscopic/surgical) local excision of the primary tumour prior to study-entry
• Prior pelvic radiotherapy

Age

• Concomitant or previous malignancies within 3 years prior to trial entry, except those that in the opinion of the MDT are unlikely to relapse < 3 years or lead to death < 5 years

Other

• Definite evidence of regional or distant metastases (M1) in opinion of MDT
• Pregnant or lactating women.
• Pre-existing faecal incontinence, leading to an expected impaired quality of life post-treatment
• MRI suspicious lymph nodes cN1 (1-3 lymph nodes > 8mm) or cN2
• MRI extramural vascular invasion (mriEMVI) present (defined by protocol guidelines)
• MRI defined mucinous tumour
• Mesorectal fascia threatened by tumour (≤ 1mm on MRI)

• Biopsy proven adenocarcinoma of the rectum
• Early- or early-intermediate stage rectal cancer, defined as Magnetic Resonance Imaging (MRI)-T1-3ab, N0/N1 (≤3 mesorectal lymph nodes ≤8mm), MX/M0 rectal tumour
• Tumour located in the distal or mid-rectum for which TME-surgery is required
• Eastern Cooperative Oncology Group (ECOG) performance status 0-1
• Age 18 years or older
• Patient able and willing to provide written informed consent for the study