Radiation Therapy Techniques for Breast Cancer

Radiation Therapy in women treated with breast conserving surgery is typically delivered to the whole (entire) breast. Treatment often consists of two angled (tangential) beams designed to minimize dose to the underlying normal lung tissues. A similar approach may be used in women treated to the chest wall following mastectomy.

Treatment Plan of an early stage right-sided breast cancer patient treated with two tangential radiation beams

In women found to have lymph node involvement, radiation is also often delivered to the regional lymph nodes (axillary and supraclvacular regions).  In these women, additional radiation beams are matched to the tangential (breast) fields.

Regional lymph node irradiation in a breast cancer patient with involved lymph nodes. Treatment is delivered with a single field encompassing both the supraclavicular and axillary lymph nodes.  The shoulder joint is shielded to minimize toxicity.

Whole breast irradiation is typically delivered in 2 phases. Initially, a dose of 50.4 Gy is administered over 5½ weeks. Treatment is then completed with an additional 10 Gy “boost” delivered over 5 days to the lumpectomy cavity alone.

Unlike the initial whole breast treatment which is delivered with photons, the boost may be delivered with a different type of radiation known as electrons, which deposit dose more superficially.