Trial Outcomes & Findings for A Trial of 15 Fraction vs 25 Fraction Pencil Beam Scanning Proton Radiotherapy After Mastectomy in Patients Requiring Regional Nodal Irradiation (NCT NCT02783690)

A Trial of 15 Fraction vs 25 Fraction Pencil Beam Scanning Proton Radiotherapy After Mastectomy in Patients Requiring Regional Nodal Irradiation

Will be defined as the percentage of women randomized who develop one or more of the following events: grade 3 or higher late adverse events; unplanned surgical intervention (not including planned serial fat grafting) in patients who undergo mastectomy with reconstruction.

Acute adverse events are defined using Common Terminology Criteria for Adverse Events (CTCAE) version 4. Grade 1 or 2 events occurring in at least 10% of patients are reported along with all grade 3 or higher events.

Late adverse events are defined using CTCAE version 4. Grade 1 or 2 events occurring in at least 10% of patients are reported along with all grade 3 or higher events.

A failure is defined as loss of the tissue expander or implant with the inability to replace it resulting in no final reconstruction or conversion to autologous reconstruction or revised with the addition of autologous reconstruction.

measured by cosmesis evaluation and the Breast Cancer Treatment Outcome Scale (BCTOS)

measured by reviewing digital photographs and the 4 point (excellent, good, fair, poor) adaptation of the Harvard Cosmesis Scale

Will be defined as local recurrence from trial registration as a first event at 5 years. The IBTR cumulative incidence will be estimated using a competing risks method by treatment arm. The competing risks will be regional/distant breast cancer recurrence and death. The percentage of patients with IBTR is defined as the number of patients that have a IBTR divided by the number of patients treated in each arm.

Will assess metastatic cancer that has either been biopsy confirmed or clinically diagnosed as recurrent invasive breast cancer at 5 years. The percentage of patients with a distant recurrence is defined as the number of patients that have a distant recurrence divided by the number of patients treated in each arm.

Defined as invasive breast cancer in the axilla, regional lymph nodes, chest wall, and skin of the ipsilateral breast at 5 years. The percentage of patients with a regional recurrence is defined as the number of patients that have a regional recurrence divided by the number of patients treated in each arm.

DFS is defined as the time from study registration until the occurrence, if any, of one of the following events: invasive IBTR, regional invasive breast cancer recurrence, distant breast cancer recurrence, death due to any cause, contralateral invasive breast cancer, and second primary non-breast invasive disease. DFS at 3 years will be reported as the percent of patients without a DFS event at 3 years post radiotherapy.

Overall survival is defined as the time from registration to death due to any cause. OS at 3 years is reported as the percentage of patients still alive and in follow up at 3 years post radiotherapy.