Inclusion Criteria:

- 18 years of age or older

- Clinical (i.e. surgical determination) and/or diagnostic image findings consistent
with c/uT4 or CRM+ (note that CRM+ must be established by MRI), primary rectal
Adenocarcinoma (i.e. histology consistent with origin from rectal mucosa); these
constitute LARC for the purpose of this protocol

- Treatment will be directed at the primary cancer, being clinically appropriate and
given with an initial intent to cure the patient (this includes accepting up front
that radiation and surgery are feasible; for surgery, this means that the patient has
been determined fit for major surgery by an anaesthesiologist prior to the request
for randomization)

- Performance status is sufficient to undertake the treatment in either arm (KPS>50%)

- Patient is accessible for required follow-up and data collection

- Radiation oncologist expects survival to exceed 6 months from date of diagnosis

- Patient provides informed consent

Exclusion Criteria:

- Recurrent rectal cancer

- Primary wholly in the sigmoid colon

- Considered to be arising in the anal canal

- Metastatic disease beyond the pelvis (by clinical assessment and/or diagnostic
imaging)

- Contraindications to protocol RT or to protocol chemotherapy, such as one or more of
the following:

- any prior RT to the pelvis; a solitary pelvic kidney within the intended radiation
volume

- consideration by the most responsible radiation oncologist that the treatment volume
is too large, or the amount of small bowel or other critical organs within the
treatment volume is too much for safe treatment

- significantly abnormal laboratory tests such as impaired renal/liver function

- a haemoglobin that is < 8.0 (or 80, SI) and the patient is not transfused to exceed
8.0 (or 80, SI)

- on-going medications that are not compatible with protocol neo-adjuvant chemotherapy
as described in this protocol

- Significant development issues (such as with age < 18 yr)

- Co-morbidity

- Psychiatric diagnosis

- Physical impairment

- Pregnancy or continuing breast-feeding, that precludes administration of protocol
treatments, or that precludes data collection (such as likely to preclude follow-up
visits or completing questionnaires)