Inclusion Criteria:

1. Histologically confirmed, non-metastatic adenocarcinoma of the prostate, previously
untreated (other than by neoadjuvant hormonal treatment)

2. National Collaborative Cancer Network locally advanced disease (T3b± or T4)43 or:

• Estimated risk of pelvic lymph node involvement ≥30% * and either:

- Gleason 9 or 10 or

- Gleason 8 and one other high risk feature (T3± disease or PSA >20) or

- Gleason 7 and 2 high risk features (T3± disease and PSA ≥30)

3. WHO performance status 0 or 1

4. Normal blood count (Hb > 11g/dl, WBC >4000/mm3, platelets >100,000/mm3)

5. LHRH analogue therapy for 6-9 months duration prior to proposed radiotherapy
treatment and PSA < 4ng/ml prior to randomisation.

6. Age ≥ 18 years

7. Patients must be prepared to attend follow up. All patients participating in the
Patient Reported Outcomes (PRO) Study must have adequate cognitive ability to
complete the PRO questionnaires.

8. Written informed consent

- T3a disease should be demonstrated convincingly, either clinically or by MRI.
T3b disease (seminal vesicle involvement) must be convincingly demonstrated on
MR.

- Risk of pelvic lymph node involvement = (Gleason score - 6) x 10 + 2/3 PSA

Exclusion criteria:

1. Prior pelvic radiotherapy

2. Prior major pelvic surgery (e.g. colectomy, colostomy, cystectomy, prostatectomy)*

3. Radiologically suspicious (short axis diameter ≥1.0cm unless biopsied and negative)
or pathologically confirmed lymph node involvement

4. Life expectancy < 5 years

5. Castrate resistant prostate cancer (rising PSA after LHRHa and anti-androgen)

6. Previous active malignancy within the last 5 years other than basal cell carcinoma

7. Co-morbid conditions likely to impact on the decision to treat with radiotherapy
(e.g. previous inflammatory bowel disease, previous colo-rectal surgery, significant
bladder instability or urinary incontinence)

8. Bilateral hip prosthesis or fixation which would interfere with standard radiation
beam configuration

- Patients who have undergone minor pelvic surgery will be eligible (eg
appendicectomy, trans urethral resection of prostate (TURP), exploratory
laparoscopy, haemorrhoidectomy, inguinal/femoral hernia repair)