Radiotherapy treatment in breast cancer

Radiotherapy is commonly used in the management of breast cancer.

A meta-analysis has been shown that radiotherapy reduces the local recurrence rate by about two-thirds and significantly reduces breast cancer-related deaths (1).

However this study reveals that radiotherapy does increase other causes of death especially vascular disease - probably because the heart, coronaries and carotids are included in the irradiated field. Of note is that historical methods of radiation included overlapping fields, high daily doses, and larger irradiated volumes, all of which may increase mortality from causes other than breast cancer. This meta-analysis suggests that mortality from such causes may be lower when daily doses of < 2.2 Gy were employed.

This evidence suggests that many patients, especially those who are younger and node positive, should consider nodal irradiation, even when systemic treatment is given.

NICE suggest that (2):

• radiotherapy after breast conserving surgery
  • patients with early invasive breast cancer who have had breast conserving surgery with clear margins should have breast radiotherapy
  • offer adjuvant radiotherapy to patients with DCIS following adequate breast conserving surgery and discuss with them the potential benefits and risks
• radiotherapy after mastectomy
  • offer adjuvant chest wall radiotherapy to patients with early invasive breast cancer who have had a mastectomy and are at a high risk of local recurrence. Patients at a high risk of local recurrence include those with four or more positive axillary lymph nodes or involved resection margins.
  • do not offer radiotherapy following mastectomy to patients with early invasive breast cancer who are at low risk of local recurrence (for example, most patients who are lymph node-negative)

Reference:

• 1. Early Breast Cancer Trialists' Collaborative Group. (2000). Favourable and unfavourable effects on long-term survival of radiotherapy for early breast cancer: an overview of the randomised trials. Lancet 355, 1757-70.
• 2. NICE (March 2017).Early and locally advanced breast cancer - dagnosis and treatment