Inclusion Criteria:

Primary tumour characteristics:

1. Histological proof of newly diagnosed primary adenocarcinoma of the rectum

2. Locally advanced tumour fulfilling at least one of the following criteria on pelvic
MRI indicating high risk of failing locally and/or systemically (T4a, i.e. overgrowth
to an adjacent organ or structure like the prostate, urinary bladder, uterus, sacrum,
pelvic floor or side wall (according to TNM version 5), cT4b, i.e. peritoneal
involvement, extramural vascular invasion (EMVI+). N2, i.e. four or more lymph nodes
in the mesorectum showing morphological signs on MRI indicating metastatic disease.
Four or more nodes, whether enlarged or not, with a rounded, homogeneous appearance
is thus not sufficient. Positive MRF (previously named CRM), i.e. tumor or lymph node
< 1 mm from the mesorectal fascia. Enlarged lateral nodes, > 1 cm (lat LN+)

Exclusion Criteria:

1. Extensive growth into cranial part of the sacrum (above S3) or the lumbosacral nerve
roots indicating that surgery will never be possible even if substantial tumour
down-sizing is seen

2. Presence of metastatic disease or recurrent rectal tumour

3. Familial Adenomatosis Polyposis coli (FAP), Hereditary Non-Polyposis Colorectal
Cancer (HNPCC), active Crohn¡¦s disease or active ulcerative Colitis

4. Concomitant malignancies, except for adequately treated basocellular carcinoma of the
skin or in situ carcinoma of the cervix uteri. Subjects with prior malignancies must
be disease-free for at least 5 years

5. Known DPD deficiency

6. Any contraindications to MRI (e.g. patients with pacemakers)

7. Medical or psychiatric conditions that compromise the patient's ability to give
informed consent

8. Concurrent uncontrolled medical conditions

9. Any investigational treatment for rectal cancer within the past month

10. Pregnancy or breast feeding

11. Patients with known malabsorption syndromes or a lack of physical integrity of the
upper gastrointestinal tract

12. Clinically significant (i.e. active) cardiac disease (e.g. congestive heart failure,
symptomatic coronary artery disease and cardiac dysrhythmia, e.g. atrial
fibrillation, even if controlled with medication) or myocardial infarction within the
past 12 months

13. Patients with symptoms or history of peripheral neuropathy