Toxicity from Radiation in Breast Cancer

Breast cancer is probably among the most common diagnoses found on daily patient treatment lists in the majority of Radiation Oncology departments. This makes understanding what type of toxicity to expect from radiation for breast cancer and its management of prime importance, since it affects significant numbers of patients daily. Radiation for breast cancer is predominantly to the intact breast for early stage disease with post-mastectomy radiation comprising a smaller proportion of radiation delivered for this diagnosis. The acute toxicity that develops as well as the type of late sequelae that can occur in each of these treatment scenarios is similar. During intact breast or chest-wall radiation, the organs commonly at risk for radiation injuries that manifest as acute and late toxicity include skin, chest wall, lung, and heart. When regional nodal irradiation is added, the shoulder, brachial plexus, and axillary lymphatics are also at risk for potential injury.

In general, radiation for breast cancer post-lumpectomy and post-mastectomy is very well tolerated by most patients and does not significantly impair their daily activities. Acute side effects of treatment are generally common in occurrence, self-limiting, and resolve within 4–6 weeks after the treatment is completed. Skin reactions and the constitutional symptom of fatigue dominate the early toxicity profile. Late toxicity or permanent sequelae can be divided into two groups: the more common effects on the appearance of the breast such as persistent breast edema, hyperpigmentation, and fibrosis and those that are very uncommon but can have significant health consequences as a result of permanent injury to other organs such as brachial plexopathy, radiation pneumonitis, cardiac morbidity, or secondary malignancy.