Inclusion Criteria:

1. Patients with biopsy verified adenocarcinoma in the rectum ≤ 10 cm from the anal
verge.

2. T3/4 tumor assessed by transrectal ultrasound and MR, and CRMMR < 5 mm.

3. Life expectancy of more than 3 months.

4. Age ≥18 years.

5. Performance status ≤ 2 according to WHO.

6. Patient able to observe protocol guidelines.

7. Signed informed consent.

Exclusion Criteria:

1. Previous radiation treatment for the pelvis.

2. Known distant metastases.

3. Serious disease contraindicating treatment, including cardiovascular disease.

4. Other malignant disease apart from curativly treated non-melanotic skin cancer and
previously treated carcinoma in situ cervicis uteri.

5. Pacemaker

6. other disease making the patient unfit for study participation as assessed by
investigator