Partial breast irradiation for early breast cancer (Review)

Free to read Plain language summary: Partial breast irradiation for early breast cancer What is the issue? Women with early breast cancer who choose to keep their breast need to have radiotherapy (RT) as well as surgery to remove the cancer to make sure it does not regrow in the breast. RT is treatment with high energy x-rays. Having RT for breast cancer usually means 25 to 30 visits to the RT department, five times per week. If breast cancer does regrow in the same breast (called local recurrence), it tends to come back in the area it was removed from. Women can also grow a new cancer (new 'elsewhere primary') in another part of the same breast. We are not sure if the RT given to stop cancer regrowth where the first cancer was does stop the growth of 'elsewhere primaries'. Breast cancer is the most common cancer that women get. When women choose to keep their breast, it is important that they are happy with how it looks after treatment (cosmesis). Why does it matter? We always want to treat the smallest area we can with RT because this means fewer side effects. Treating only part of the breast could mean that RT might be able to be used again in another part of the same breast if needed. New ways of giving RT mean that treating part of the breast can be done with fewer treatments. This is likely to be easier for women and cost less money. We asked if giving RT to part of the breast (called partial breast irradiation (PBI)) is as good as giving RT to the whole breast. It would need to control the cancer as well as giving RT to the whole breast does. It would also be important that the PBI gives about the same side effects and breast appearance as treating the whole breast. We found seven studies, which involved 7586 women. Our evidence is current to May 2015. Local recurrence was rare, but more common with PBI (low-quality evidence) and the breast appearance (scored by doctors) was worse with PBI (low-quality evidence). Survival did not differ (high-quality evidence). Scarring in the breast was worse with PBI (moderate-quality evidence). The same number of women died of breast cancer with either treatment (moderate-quality evidence). The same number of women developed spread of breast cancer around their body with either treatment (moderate-quality evidence). There appeared to be the same number of women who eventually needed the breast removed (mastectomy) after both treatments. Mastectomy could happen because of cancer regrowth in the breast or bad side effects (low-quality evidence). This means that at the moment, PBI does not give the same cancer control in the breast as treating the whole breast, but the difference was small. It may cause worse side effects. There are five big ongoing studies that will be important to answer this question. We hope to have a clearer answer in the next update of this review.