A change in postmastectomy radiotherapy fractionation: an audit of tumour control, acute and late morbidity

In order to determine if a change in radiotherapy fractionation, which reduced the radiation dose per fraction without changing total overall dose, would reduce acute and late morbidity without reducing local control of disease or survival in patients who had undergone mastectomy for breast cancer, a non-randomized retrospective study of case records and measurement of late radiation morbidity both clinically (generally by one clinician) and radiologically was performed. This audit was performed in the Department of Clinical Oncology in Edinburgh, a centre serving a population of approximately 1.2 million and receiving at that time approximately 500 new breast cancer patient referrals each year. The patients studied were those referred between January 1979 and December 1984 with the fractionation change occurring in April 1982. The case record reviews were carried out in both 1987 and 1993. Between 1979 and 1984, 2739 patients with breast cancer were referred to the department. Of these 821 underwent simple mastectomy as primary treatment followed by radiotherapy. Forty-eight of those were excluded (44 received non-standard radiotherapy and 4 case records could not be found). Of the 773 remaining, 484 underwent 10 fraction radiotherapy, and 289 underwent 20 fractions. The two groups were matched well by menstrual status, clinical stage, and histology. In each group the radiation therapy dose was generally 45 Gray. Late morbidity could be assessed in 79 of the 10 fraction cohort and 92 of the 20 fraction cohort. Locoregional relapse and survival were not affected by this change. Acute skin morbidity was significantly decreased in the 20 fraction cohort while late skin, subcutaneous and rib morbidity were also markedly reduced in this group. There was a slight increase in acute pneumonitis. Arm oedema was not significantly affected.