Whole-breast radiotherapy after breast-conserving surgery: usually tangential fields or tangent-like IMRT, delivered in 15, 16 or 5 fractions, sometimes with a boost to the tumor bed. The main planning problems are dose homogeneity across a curved target and keeping the heart and lung out of the tangents.
Whole-breast treatment after breast-conserving surgery is now mostly hypofractionated. Common schedules are 40.05 Gy in 15 fractions, backed by the UK START trials; the Canadian schedule of 42.56 Gy in 16 fractions, from the Whelan trial; and 26 Gy in 5 fractions from FAST-Forward.
Some patients also receive a boost to the tumor bed. It can be given sequentially after the whole breast — for example 10 Gy in 4 fractions after 42.56 Gy in 16 — or as a simultaneous integrated boost (SIB) in the same fractions, as tested in RTOG 1005 and IMPORT HIGH.
Organ limits depend on the schedule, so the constraint table below has one column for 15–16 fractions and one for 5.
Most whole-breast plans are tangents or tangent-like IMRT. Setup keeps the breast, arm and chest wall in the same place every day.
Supine on a breast board with the arm or arms above the head; knee supports, a vacuum bag or a breast-support device as needed. Prone positioning is an alternative.
Raising the arm moves it out of the tangent beams and changes the breast's shape and position, so it has to be the same at simulation and every treatment. A reproducible setup keeps the tangent geometry — and the lung and heart in the field — consistent.
Treating while the patient holds a deep breath, usually monitored with a surface or respiratory tracking system. More →
A deep breath pushes the heart down and back from the chest wall and expands the lung, which can lower heart dose. Protocols suggest considering breath-hold techniques to reduce heart, liver and lung dose; mean heart dose is linked to later coronary events.
Radio-opaque wire placed on the surgical scar and around the palpable breast tissue before the scan.
Breast tissue edges can be hard to see on CT. The wire shows the clinical extent of the breast and the scar, which helps define the target and the field edges.
A 3D CT with thin slices, scanned from the neck to below the diaphragm.
The whole lungs should be included so lung dose-volume metrics are complete.
Image fusion aligns an outside scan with the planning CT so the target can be drawn using information the CT doesn't show. For breast this means any available pre-operative imaging — mammogram, ultrasound, MRI or PET/CT. CT and MRI can be registered to the planning CT; mammograms and ultrasound are reviewed alongside it.
It shows where the tumor was before surgery, which helps locate the tumor bed for a boost. The breast changes shape between the diagnostic scan and the planning CT — with position and after surgery — so one template asks that the registration's local accuracy be checked and that a deformable registration keep the breast's shape.
What each volume represents. Expansions and dose levels come from your protocol.
The lumpectomy cavity: the seroma and the surgical clips where the tumor was removed.
It is the target for a sequential boost or SIB. Clips and seroma make it visible on CT; without them, finding the cavity relies on scars and pre-operative imaging.
The glandular breast tissue visible on CT, guided by the wire placed around the clinical breast.
Atlases define where the breast stops — against the pectoral muscle, under the skin and at the top and bottom — and the definition changes the size of the volume and the lung and heart dose.
An expansion of the CTV for setup uncertainty, plus an evaluation structure cropped back from the skin surface and from beyond the chest wall.
The PTV reaches into air and the build-up region, where full dose isn't expected. Coverage and hotspots are judged on the cropped evaluation volume instead.
The planning volume around the tumor bed for a boost.
With a SIB, one plan carries two dose levels: coverage of each target and the hotspot in the breast around the boost both need checking.
Click an organ for its anatomy, why it matters and contouring resources. Superscripts link to the study behind each value.
| Organ | 40.05 Gy / 15 fxor 42.56 Gy / 16 fx | 26 Gy / 5 fxFAST-Forward |
|---|---|---|
| Ipsilateral LungTangents: central lung distance <3 cm, ideally ≤2 cm. |
| |
| Contralateral Lung |
| — |
| Heart / PericardiumKeep mean dose as low as reasonably achievable; <2 Gy is often achievable. Consider breath hold. | ||
| LAD (Left Anterior Descending Artery)Left-sided treatment. Max ≤17 Gy is for 40 Gy / 15 fx. | — | |
| Contralateral BreastKeep as low as reasonably achievable, especially with VMAT or fields crossing the midline. | — |
Values quoted from eviQ 3650 (last reviewed 28 March 2024; review due 30 June 2028), DEGRO 2019 and DBCG HYPO 2021, checked by DoseLab on 2026-09-23. Verify against your protocol, institutional policy and physician directive before clinical use.
Ten-year follow-up of the UK START A and B trials of hypofractionated breast radiotherapy. Citation as given in the eviQ reference list; not yet checked against the journal.
Ten-year results of the Ontario Clinical Oncology Group randomized trial comparing 42.5 Gy in 16 fractions with 50 Gy in 25 fractions of whole-breast irradiation after breast-conserving surgery, without a boost. Many clinics prescribe the schedule as 42.56 Gy (2.66 Gy × 16). Citation as given in the eviQ reference list; not yet checked against the journal.
Five-year results of the UK FAST-Forward trial, comparing one week of whole-breast or chest wall radiotherapy with three weeks. Citation as given in the eviQ reference list; not yet checked against the journal.
NRG Oncology's protocol page for RTOG 1005, a phase 3 trial of hypofractionated whole-breast irradiation with a concurrent (SIB) boost. The protocol document holds the trial's dose–volume requirements, set separately for each arm: Arm I (50 Gy in 25 fractions, sequential boost) and Arm II (40 Gy in 15 fractions, concurrent boost to 48 Gy). Both arms are tangent-style whole-breast treatment without nodes, and skin bolus was not allowed. DoseLab checked the 50 Gy / 25 fx ipsilateral lung limits against section 6.4.3.5 of the 24 May 2011 version.
Results of the UK IMPORT HIGH trial of dose-escalated simultaneous integrated boost radiotherapy. Citation as given in the eviQ reference list; not yet checked against the journal.
Population-based case-control study relating mean heart dose to later major coronary events after breast radiotherapy. Citation as given in the eviQ reference list; not yet checked against the journal.
The heart chapter of the 2010 QUANTEC supplement, covering pericarditis and long-term cardiac effects and the dose–volume relationships reported for them. A later letter in the same journal comments on its breast-cancer conclusions.
NRG Oncology's breast downloads page, which links the RTOG Breast Cancer Atlas for Radiation Therapy Planning, an NRG whole-breast radiation therapy template and the RADCOMP breast atlas.
ESTRO consensus on target volume delineation for elective breast and nodal radiotherapy, with a version 1.1 correction published in 2016. Citation as given in the eviQ reference list; not yet checked against the journal.
Endorsed eviQ protocol for adjuvant whole-breast radiotherapy after breast-conserving surgery. DoseLab's whole breast constraint table reproduces selected values from its organs-at-risk table, keeping eviQ's citation for each. For SIB and 5-fraction planning, the protocol points to the RTOG 1005, IMPORT HIGH and FAST-Forward trial protocols.