Post-Prostatectomy (Prostate Bed)

Overview

Post-prostatectomy radiotherapy treats the prostate bed after surgery — either soon afterwards (adjuvant) or when PSA rises (salvage). The target can’t be seen, so contouring follows consensus atlases, and the bladder and rectum sit closer to the target than in intact-prostate treatment.

How It Differs From Definitive Treatment

After radical prostatectomy there is no prostate to see. The target is the prostate bed — the space where the prostate and seminal vesicles were — defined from anatomical landmarks, surgical clips and consensus guidance rather than a visible organ.

Radiotherapy may be given soon after surgery (adjuvant) or when PSA rises (salvage). Randomized trials — RAVES and RADICALS-RT — compared those approaches. Protocols give both conventional (2 Gy per fraction) and hypofractionated (2.63 Gy per fraction) schedules, and the constraint table below has a column for each.

Without the prostate in between, the bladder and rectum wrap more closely around the target, and post-surgical anatomy (the vesicourethral anastomosis, clips, altered bladder shape) needs careful review on the planning CT.

Simulation & Daily Setup

Bladder and rectal preparation
Consistent bladder and rectal filling keep the prostate bed in the same place each day.

What is it?

A consistent, comfortably full bladder and an empty rectum, as for definitive treatment.

Why does it matter?

The bladder moves the anterior prostate bed with filling, and the rectum sits directly behind it; consistency from day to day matters as much as in intact-prostate treatment.

Image fusion — PSMA PET and MRI
PSMA PET before salvage treatment shows where recurrent disease is; MRI helps with the anastomosis and any local recurrence.

What is it?

Image fusion aligns an outside scan with the planning CT so the target can be drawn using information the CT doesn't show. Before salvage treatment to the prostate bed, a PSMA PET is recommended — particularly when the PSA is 0.2 ng/mL or higher — and a pelvic MRI when a local recurrence is seen.

Why does it matter?

PSMA PET can show where the recurrence is — in the bed, the pelvic nodes or beyond — before the target is decided. A negative scan is not a reason to skip salvage treatment. MRI helps define the urethro-vesical anastomosis, the CTV and any visible recurrence. The bed moves with bladder and rectal filling, so check the registration around the bed itself.

Image guidance
With no prostate left for fiducials, daily matching relies on soft tissue, surgical clips or bone.

What is it?

Daily imaging matched on soft tissue, surgical clips or bony anatomy, depending on department policy.

Why does it matter?

There are no fiducials in a prostate that is no longer there. Clips can help but may not move with the bed; soft-tissue matching on the bladder and rectum is often used alongside them.

Target Delineation

Consensus atlases define the prostate bed; margins and nodal decisions come from your protocol.

CTV — Prostate bed

Definition

The region of the former prostate and seminal vesicles, including the vesicourethral anastomosis, defined by anatomical boundaries.

Why it matters

Because the target is not visible, contouring consistency depends on following a consensus atlas. The RTOG consensus guideline is the common starting point.

Contouring resources

Organ contouring guides →

Pelvic nodes — Elective nodal CTV

Definition

Pelvic lymph node regions, treated in some salvage situations.

Why it matters

Some protocols include schedules that treat pelvic nodes alongside the bed, which brings small bowel into consideration.

Contouring resources

Organ contouring guides →

PTV — Planning Target Volume

Definition

An expansion for setup and motion uncertainty.

Why it matters

The bed moves with bladder and rectal filling, and there is no internal marker to follow it directly, which shapes how margins are chosen.

Contouring resources

Organ contouring guides →

Organs at Risk & Dose Constraints

Click an organ for its anatomy, why it matters and contouring resources. Superscripts link to the study behind each value.

Organ64–66 Gy / 32–33 fx2 Gy per fraction52.5 Gy / 20 fx2.63 Gy per fraction
Rectum
  • V50 Gy <50%1,2
  • V66 Gy <30%1,2
  • V40 Gy <60%3
  • V52.5 Gy <30%3
Bladder
  • V65 Gy <50%4,5
  • V70 Gy <35%4,5
  • V40 Gy <80%3
  • V48 Gy <50%3
Femoral Heads
  • V50 Gy <5%4
  • V43 Gy <5%6
Small Bowel
  • Peritoneal cavity V45 Gy <195 cc5
  • D1 cc <46 Gy (EQD2 50 Gy)6
Large Bowel / SigmoidGeneral conventional limits, not prostate-specific.
  • V45 Gy <5% or <20 cc7
  • V35 Gy <35% or 150 cc7
—
References (7)
  1. RAVES — Adjuvant radiotherapy versus early salvage radiotherapy following radical prostatectomy (TROG 08.03/ANZUP RAVES): a randomised, controlled, phase 3, non-inferiority trial. Lancet Oncol. 2020;21(10):1331–1340 Source
  2. RADICALS-RT — Timing of radiotherapy after radical prostatectomy (RADICALS-RT): a randomised, controlled phase 3 trial. Lancet. 2020;396:1413–1421 Source
  3. RADICALS-HD — Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial. Lancet. 2024;403(10442):2416–2425 Source
  4. ENZARAD protocol — ENZARAD (ANZUP 1303): a randomised phase 3 trial of enzalutamide in androgen deprivation therapy with radiation therapy for high risk, clinically localised, prostate cancer. ENZARAD / ANZUP 1303 trial protocol Source
  5. QUANTEC — QUANTEC — Quantitative Analyses of Normal Tissue Effects in the Clinic. Int J Radiat Oncol Biol Phys. 2010;76(3 Suppl):S1–S160 Source
  6. eviQ 4487 — Prostate adenocarcinoma prostate bed salvage or adjuvant EBRT (eviQ ID 4487). eviQ Radiation Oncology protocol 4487 Source
  7. NCCN Anal Cancer v2.2022 — NCCN Clinical Practice Guidelines in Oncology — Anal Cancer, Version 2.2022. NCCN Guidelines, Anal Cancer, Version 2.2022 Source

Values quoted from eviQ 4487 (first approved 7 November 2024; review due 31 December 2026) and CORSAIR, checked by DoseLab on 2026-09-22. Verify against your protocol, institutional policy and physician directive before clinical use.

Search all prostate constraints in the Constraint Finder →

Protocols & Literature

All prostate literature →