Whole Breast Radiotherapy


Conventional setup is:

  • Patient supine on a breast board
    • The breast board angles the patient's sternal contour with the horizontal plane, provides accurate immobilisation for the heads, arms and buttocks as well as patient comfort.
    • The alignment of the sternal contour to the horizontal is important as it allows the tangent to enter the patient's volume at the same point along the midline; this prevents missing of superior or inferior parts of the chest wall at the midline.
  • Arms abducted to over 90 degrees and externally rotated
  • Knee immobilisation
  • Bolus is not required for irradiation when the breast is present, and leads to poor cosmesis if used.

Other techniques include lateral decubitus position for large breasted women, or prone position to allow the breast tissue to fall away from underlying lung/heart. These techniques have much less evidence and are not routinely used.

In large breasted women, other techniques may be used to obtain accurate positioning. This includes the use of vacuum bags to support pendulous breasts or using thermoplastic moulds to assist the breast in maintaining the same position.

Beam arrangement

The most common arrangement of beams is tangential, with the posterior border of the beam angled to cover the breast and chest wall tissue at risk of recurrence. Importantly, the isocentre is usually placed the superior border of the tangential fields to prevent divergence into the supraclavicular fossa or axilla, which are treated using direct or opposed fields. Routine boundaries are:

  • The medial margin placed at the midline
  • The lateral margin placed 2 cm posterior to palpable breast tissue
  • The superior margin at the suprasternal notch
  • The inferior margin placed 2 cm below the inframammary fold

A variable amount of lung tissue is included, which depends entirely on:

  • The points chosen for the medial and lateral beam border
  • The shape of the patient's chest contour
  • The amount of subcutaneous fat present

Lung tissue is estimated by drawing a line from the medial to lateral borders of the tangents. There are no set guidelines for the amount of lung tissue that lies between the posterior tangential border and the chest wall; most consultants will keep this under 3 cm to spare the lung tissue.

Beam Energy

For most women, opposed tangential beams with 6 MV photons will provide a homogenous dose throughout the breast tissue. For larger separations (22 cm +) high energy beams may be necessary to provide homogeneity; these higher energies may be mixed with a 6 MV beam for best results.


Conventional dosing is 50 Gy in 25 fractions over 5 weeks, followed by an electron boost to the tumour bed/scar of 10 Gy in 5 fractions (see Boost below). This has been challenged by several studies:

  • The Ontario study (Whelen et al), which employed 42 Gy in 16 fractions over 3 weeks with no boost, demonstrated similar results between their scheme and conventional fractionation in the absence of a boost.
  • The Royal Marsden study (Yarnold et al, compared 40 Gy/15 #, 39 Gy/13 #, and 50 Gy/25#; there was a poorer control in the 39 Gy group but similar control and cosmetic results in the 40 Gy compared with the 50 Gy group. Boosts were used in this trial but were larger than conventional - 14 Gy / 7 fractions.

Post-Mastectomy Radiotherapy

Chest wall radiotherapy is similar to whole breast radiotherapy with a few significant differences:

  • The lack of a breast makes clinical markup a bit trickier. The normal contralateral breast, if present, can be used as a guide. Alternatively, 2 cm below the 6th intercostal space can be used as this is the normal inferior extent of breast tissue.
  • Bolus should be applied to the chest wall to ensure adequate skin dosage. 0.5 cm is typically used. The extent of bolus depends on consultant and there is no consensus - either the entire chest wall is covered, or simply a region over the mastectomy scar (usually 3 cm distant). Skin reaction should be brisk but not cause treatment interruption.
  • The standard dose is 50 Gy in 25 fractions; there is no evidence for the use of hypofractionated techniques.
  • Immediate reconstruction before radiotherapy is a bad idea; there is evidence of significantly poorer outcomes particularly with implants rather than autologous tissue reconstruction. Reconstruction can also causes difficulties in planning. Avoid.
  • Implant reconstruction after radiation is also problematic due to reduced tissue complicance. Ideally patients should have a delayed autologous tissue reconstruction.

Special Topics

Hypofractionated Radiotherapy Treatments

Breast Boost

Intensity Modulated Breast Radiotherapy

Prone Treatment

Treatment of Regional Nodes

Accelerated Partial Breast Irradiation

Breast Reconstruction after Radiotherapy