Patients with cancer often question whether the risks and adverse effects associated with a specific treatment outweigh the benefits. This decision is highly personal and dependent on individual values and goals. Many patients value independence and quality of life over cancer recurrence and rely on physicians to recommend treatments that align with those goals.

Although radiotherapy after breast conserving surgery is usually well tolerated, adverse effects include telangiectasia, breast pain, induration, retraction, and rarely secondary cancers and ischemic cardiac disease. Some women at low risk for local recurrence may forego radiation therapy, but outcome studies are needed to predict the effect on recurrence risk.

Investigators of the prospective LUMINA cohort study examined the incidence of local recurrence associated with omitting radiotherapy following breast conserving surgery and endocrine therapy in a subset of 500 women with a new diagnosis of low-risk invasive breast cancer. The women were ≥55 years of age, had a primary tumor < 2 cm in diameter, negative axillary nodes, and luminal A breast cancer, which is the least proliferative and associated with the best prognosis.

At 5 years, the incidence of local recurrence associated with the omission of radiotherapy was 2.3% (90% confidence interval, 1.3 to 3.8). This rate will likely increase after longer follow up. In a recent study and a study published in 2013, 10-year recurrence rates approximated 10% in patients with early breast cancer who had omitted radiotherapy. Therefore, longer follow up of the Lumina study is needed to guide patient-physician conversations regarding long-term risks of foregoing radiotherapy, as many breast cancer survivors now live 20 to 30 years after treatment, even those diagnosed at a relatively older age. In the meanwhile, women with low-risk breast cancer who are aged 55 years and older can use these data to help inform decisions about whether to include radiotherapy in their treatment plan.