Breast cancer is an important disease for women, with one in eight women in the United States and Australia and one in nine women in the United Kingdom being diagnosed with the condition by age 85 years. Breast conserving therapy (removing the tumour but keeping an intact breast) has proven to be as effective as mastectomy (removing the breast tissue) in terms of survival for women with cancer confined to the breast (or the local lymph nodes, or both), as long as a five to six-week course of radiation therapy is delivered. This involves 25 to 30 visits to a radiation oncology department. Without radiation therapy after breast conserving surgery there is a significant risk of breast cancer returning in the breast (local recurrence) in as many as 30 to 40 women per 100. Furthermore, for every local recurrence avoided with radiation, one death is avoided at 15 years. Many women prefer breast conservation which has resulted in an increased demand for radiation services. Giving fewer radiation treatments (fractions) would be beneficial to women if this has the same effect on tumour control and survival and cosmetic outcome. In order to reduce the number of treatments, the radiation dose delivered per fraction is increased. This may also reduce demand on radiation resources and be more convenient for women.
Four trials, involving 7095 women, were included in this review. Local recurrence was not significantly different for women having fewer treatments. Breast appearance was not significantly different for women undergoing fewer treatments. Survival was not altered by having fewer treatments and there was no significant difference in late skin toxicity or radiation toxicity. Acute skin toxicity is decreased with fewer treatments. Most of the women in the trials (89.8%) had tumours less than 3 cm in size, all had complete removal of the tumour on pathology and 79% had no evidence of cancer in their lymph nodes. Where the breast size was known, 87% had small or medium breasts. This review indicates that for women who fit these criteria, using fewer radiation treatments after tumour removal is a safe and effective option. Long-term follow up (> 5 years) is available for a small proportion of the total number of patients randomised. Ongoing follow up is required for a more complete assessment of the impact of larger than standard fraction size on local recurrence rates, toxicity and breast appearance.