Adjuvant chest wall radiotherapy for breast cancer: black, white and shades of grey.

BACKGROUND

Adjuvant chest wall irradiation after mastectomy remains a core and highly effective element in the loco-regional management of early breast cancer. While the evidence base for postmastectomy radiotherapy (PMRT) in patients with 4 or more involved axillary nodes is robust, its role in 'intermediate' risk patients with 1-3 involved nodes is unclear and practice varies. Traditionally patients have been selected for PMRT on the basis of clinic-pathological factors such tumour size, nodal status, tumour grade and presence of lymphovascular invasion. However these factors alone may not predict the response of individual patients to radiotherapy. There is recent evidence that biological factors such as oestrogen and progesterone receptor and HER-2 status may also influence survival as well as loco-regional control.

METHODS

A literature review was undertaken, searching Pubmed using the mesh heading of 'breast cancer' and 'adjuvant chest wall irradiation/radiotherapy'. Priority was given to reports of meta-analyses and randomised trials of postmastectomy radiotherapy.

OBSERVATIONS

The 2005 Oxford Overview of randomised trials of postoperative radiotherapy established a clear biological link between loco-regional control and survival. Paradoxically the largest survival benefits do not occur in patients at the highest risk of recurrence. Molecular markers to identify exactly which patients are likely to benefit from PMRT are being actively investigated. Surgeons are encouraged to enter patients with 1-3 involved nodes into a clinical trial of postmastectomy radiotherapy.