Optimizing Preventive Adjuvant Linac-Based (OPAL) Radiation: A Phase 2 Trial of Daily Partial Breast Irradiation.

PURPOSE: Evidence supports use of partial-breast irradiation (PBI) in the management of early breast cancer, but the optimal dose-fractionation remains unsettled. METHODS AND MATERIALS: We conducted a phase 2 clinical trial (OPAL trial) to evaluate a novel PBI dosing schedule of 35 Gy in 10 daily fractions. Patients with close (<2 mm) margins also received a boost of 9 Gy in 3 fractions. Eligible patients underwent margin-negative lumpectomy for ductal carcinoma in situ or estrogen receptor-positive invasive breast cancer, up to 3 cm, pTis-T2 N0. The primary outcome was any grade ≥2 toxic effect occurring from the start of radiation through 6 months of follow-up. Secondary outcomes included patient-reported cosmesis, breast pain, and functional status, measured using the Breast Cancer Treatment Outcomes Scale, and physician-reported cosmesis, measured using the Radiation Therapy and Oncology Group scale. The Cochran-Armitage trend test and multivariable mixed-effects longitudinal growth curve models compared outcomes for the OPAL study population with those for a control group of similar patients treated with whole-breast irradiation (WBI) plus boost. RESULTS: All 149 patients enrolled on the OPAL trial received the prescribed dose, and 17.4% received boost. The median age was 64 years; 83.2% were White, and 73.8% were overweight or obese. With median follow-up of 2.0 years, 1 patient (0.7%) experienced in-breast recurrence. Prevalence of the primary toxicity outcome was 17.4% (26 of 149 patients) in the OPAL trial compared with 72.7% (128 of 176 patients) in the control WBI-plus-boost cohort (P < .001). In longitudinal multivariable analysis, treatment on the OPAL trial was associated with improved patient-reported cosmesis (P < .001), functional status (P = .004), breast pain (P = .004), and physician-reported cosmesis (P < .001). CONCLUSIONS: Treatment with daily PBI was associated with substantial reduction in early toxicity and improved patient- and physician-reported outcomes compared with WBI plus boost. Daily external-beam partial-breast irradiation with 13 or fewer fractions merits further prospective evaluation.

Contemporary Outcomes After Multimodality Therapy in Patients With Breast Cancer Presenting With Ipsilateral Supraclavicular Node Involvement.

PURPOSE: Patients with breast cancer and ipsilateral supraclavicular (SCV) node involvement at the time of diagnosis (TNM cN3c) have historically had poor outcomes. Radiation therapy (RT) has an important role because SCV nodes are not routinely surgically dissected. However, optimal locoregional management, contemporary outcomes, and prognostic factors are not well defined. METHODS AND MATERIALS: We reviewed the data of patients with cN3c breast cancer treated at our institution between 2014 and 2019 with curative intent, including neoadjuvant chemotherapy, surgery, and adjuvant RT. All patients received comprehensive regional RT, including to the SCV nodes. Institutional guidelines recommend a 10-Gy or 16-Gy boost to resolved and unresolved N3 nodes, respectively. Overall survival (OS), recurrence-free survival (RFS), locoregional recurrence-free survival (LRRFS), and supraclavicular recurrence-free survival (SCRFS) were analyzed. RESULTS: Data from 173 consecutive patients were analyzed with a median follow-up time of 2.8 years. The median age was 54 years, 76 patients (44%) were estrogen receptor positive/human epidermal growth factor receptor 2 negative, 100 patients (58%) had T3/4 disease, and 10 patients (6%) underwent a neck dissection. In addition, 156 patients (90%) received a cumulative SCV dose of ≥60 Gy. The 5-year OS, SCRFS, LRRFS, and RFS rates were 73%, 95%, 86%, and 50%, respectively. The 5-year OS rate for a cumulative SCV dose of ≥60 Gy versus <60 Gy was 75% versus 39% (P = .04). In the multivariable analysis, a cumulative SCV dose of ≥60 Gy, extranodal extension, receptor status, and Eastern Cooperative Oncology Group performance status were associated with OS. The 5-year SCRFS rates with and without neck dissection were 100% versus 95% (P = .57). Among patients with a postchemotherapy SCV node size of ≥1 cm without neck dissection, the 5-year SCRFS rate was 83%. CONCLUSIONS: In one of the largest series of patients with cN3c breast cancer, multimodality therapy using adjuvant RT with a SCV boost resulted in a 5-year LRRFS rate of 86%. There is a limited role for neck dissection as the 5-year SCRFS rate was 95% overall and 83% for residual SCV disease ≥1 cm after chemotherapy with RT alone. A cumulative SCV dose of ≥60 Gy was associated with improved OS, but not SCRFS, LRRFS, or RFS. A SCV boost should be considered in these patients as treatment was well-tolerated. Despite advances in systemic therapy, nearly half of patients developed distant metastases, highlighting the need for close observation after treatment.