- Arm II: Patients receive irradiation of the internal mammary and medial supraclavicular lymph node chains delivered at 1 fraction per day, 5 sessions per week, for a total of 25 fractions over 5 weeks. Radiotherapy must begin no later than 8 weeks after surgery. If adjuvant chemotherapy is given, radiotherapy begins within 6 weeks after the last course of chemotherapy and within 8 months after surgery.