GYN · Organ at risk

Bladder

Educational Summary

Dose constraints

Cervix — Definitive Chemoradiation

ScheduleConstraintSource
45–50.4 Gy / 25–28 fx
Pelvis ± nodal boost
D50% ≤45 Gy, D0.03 cc ≤50 GyNRG cervix RT template
V40 Gy <60%, V30 Gy <80%EMBRACE II

Quoted from NRG cervix RT template and EMBRACE II, checked 2026-09-30. Full table with references →

Endometrium & Cervix — Post-operative

ScheduleConstraintSource
45–50.4 Gy / 25–28 fx
Post-operative pelvis
V45 Gy ≤35%NRG endometrial RT template

Quoted from NRG endometrial RT template, checked 2026-09-30. Full table with references →

Vulva

ScheduleConstraintSource
45–50.4 Gy / 25–28 fx + boost
Composite plan (SIB or sequential boost)
D35% ≤45 Gy, D0.03 cc ≤60 GyNRG vulva RT template

Quoted from NRG vulva RT template, checked 2026-09-30. Full table with references →

Anatomy

A hollow muscular organ that sits in front of the rectum and directly above the prostate. The bladder base and neck rest on the prostate, and the bladder's shape and position change considerably with filling.

Function in the body

The bladder stores urine until it is passed.

Why it matters

Bladder dose is linked to urinary side effects — frequency, urgency, dysuria and, later, bleeding or reduced capacity. As with the rectum, limits are written as a ladder of volume thresholds, and they depend heavily on how full the bladder is: a fuller bladder pushes more of its wall (and often small bowel) away from the high-dose region. That is why simulation instructions usually ask for a comfortably full bladder and why reproducing it each day matters.

In rectal and anal cancer the bladder lies in front of the mesorectal and nodal volumes. Where it overlaps the target, a maximum-dose limit may not be achievable; one rectal protocol then suggests minimizing the bladder volume above 50 Gy instead.

In gynecologic treatment the bladder sits in front of the cervix and vagina, and its filling moves the uterus and vaginal cuff — the reason GYN simulations often scan with a full and an empty bladder to build an internal target volume. In cervix brachytherapy the bladder D2cc, in EQD2 with the external beam dose, is a planning limit, and a Foley catheter balloon marks the bladder base.

How to contour

  • Gay 2012: from the base to the dome.
  • The NRG anal cancer template: contour the outer bladder wall and fill it in as a solid structure.
  • Timmerman 2022 (Tables 8–11, written for its SBRT dose tables): the bladder wall and all urine, ending at the base of the prostate. Timmerman also defines a suprapubic bladder wall structure — the front, lower wall resting on the pubic bone, from the prostate up 2–3 cm.

Bladder filling changes the volume a lot, so follow your protocol's filling instructions.

Clinical resourceSource Verified
NRG Oncology Protocol Development Template for Radiation Therapy — Gastrointestinal Cancer: Anal Cancer
Yock A, Parker W, et al. · NRG Oncology Medical Physics Subcommittee / Radiation Oncology Committee · 2025

The template NRG Oncology gives investigators for writing the radiation therapy section of an anal cancer trial. Its example text and values are based on RTOG 0529 and the ECOG-ACRIN DECREASE trial (EA2182), and are meant to be edited for each protocol. It covers immobilization (a supine "frog-leg" position is recommended), CT or PET/CT simulation, rigid registration of MRI and PET to the planning CT, standard structure names, dose compliance tables and planning priorities.

Review articleSource Verified
A Story of Hypofractionation and the Table on the Wall
Timmerman R · UT Southwestern Medical Center · 2022

An editorial history of the UT Southwestern SABR constraint tables — often called the “Timmerman tables” — covering how they were developed and revised, and their relationship to AAPM TG-101 and NRG/RTOG protocols. Tables 2–11 separate serial tissues (listed with a volume, a volume max and a max point dose) from parallel tissues (listed with a critical volume and a critical-volume dose max). In Tables 2–7 a footnote defines “point” as ≤0.035 cm³; Tables 8–11 add a contouring-instructions column for each structure.

Further reading

  • QUANTEC — QUANTEC — Quantitative Analyses of Normal Tissue Effects in the Clinic Source
  • 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 Source
  • CHHiP (Dearnaley 2016) — Conventional versus hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: 5-year outcomes of the randomised, non-inferiority, phase 3 CHHiP trial Source
  • PACE-B — Intensity-modulated fractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-B): acute toxicity findings from an international, randomised, open-label, phase 3, non-inferiority trial Source
  • NRG cervix RT template — NRG Oncology Protocol Development Template for Radiation Therapy — Gynecological Cancer: Cervix, Uterine Cervix Source
  • EMBRACE II — The EMBRACE II study: The outcome and prospect of two decades of evolution within the GEC-ESTRO GYN working group and the EMBRACE studies Source

Related concepts