Randomized clinical studies that compare two groups often have a winner and a loser. However, the results can sometimes be a “win-win” situation. This may be the first randomized clinical study of adjuvant radiation therapy or observation after breast-conserving surgery for patients with low-risk ductal carcinoma in situ. The team, led by Beryl McCormick of MSKCC in New York, NY, expects their study to provide the basis for two major treatment options for patients with low-risk ductal carcinoma in situ after breast-conserving surgery, as their findings both support the decision to eliminate radiation therapy and confirm that radiation therapy significantly reduces the rate of recurrence in the breast. The results of the study were published in January 2015 in JCO, the leading international journal of oncology. The primary endpoint of the study was ipsilateral intramamammary recurrence. Of the 585 patients enrolled with low-risk ductal carcinoma in situ, 287 received adjuvant radiotherapy after breast-conserving surgery and 298 were not treated with radiotherapy and received observation. The median follow-up time was 7 years, and the median age of the enrolled patients was 58 years. The radiotherapy group had significantly fewer cases of local recurrence than the observation group (2 vs 19). At 7 years after breast-conserving surgery, the local recurrence rate was 0.9% in the radiotherapy group (95% confidence interval [CI], 0.0% – 2.2%) compared with 6.7% in the observation group (95% CI, 3.2% – 9.6%; hazard ratio, 0.11; P < .001). Clearly, the local recurrence rate was also lower in the observation group, yet radiotherapy still significantly reduced the local recurrence rate, as Beryl McCormick and his colleagues concluded in their article. All patients enrolled in the study (code RTOG 9804) had low-risk characteristics. These inclusion criteria may become the gold standard for defining low-risk ductal carcinoma in situ patients in the future. Of the 2 recurrent patients in the radiotherapy group, one was an invasive carcinoma and the other was a non-invasive carcinoma. In contrast, of the 19 recurrent patients in the observation group, 8 had invasive carcinoma and the other 11 had non-invasive carcinoma. The number of patients who underwent mastectomy was lower in both the radiotherapy and observation groups of recurrent patients (4 vs 8). Although adjuvant radiotherapy reduced the rate of local recurrence, the toxicity of radiotherapy was one of the major concerns of patients in the radiotherapy group. In terms of late radiation reactions, grade 1 reactions occurred in 30% of patients in the radiotherapy group, grade 2 reactions in 4.6% of patients, and grade 3 reactions in 0.7%. So in the context of such a study result, how should radiotherapists and patients with low-risk ductal carcinoma in situ make decisions about radiotherapy? The author suggests the following four-step approach: Step 1: Estimate the probability of long-term survival. This is because patients who are young and in good health are more likely to benefit from adjuvant therapy. Step 2: Assess the risks associated with radiation therapy. People with heart disease or other risk factors are more likely to forgo adjuvant radiation therapy; people with collagen vascular disease and obese patients may also forgo adjuvant radiation therapy due to skin damage and soft tissue complications. Step 3: Listen to the patient's preferences. Step 4: Explore salvage surgery measures in the event of an intramammary recurrence. Some patients' breasts may be suitable for re-breast-conserving surgery, while others may require mastectomy, and this difference can influence the decision at the time of initial treatment.