A prospective randomized study was made of 270 patients with unilateral stage I or II invasive breast cancer treated by segmental resection, axillary dissection and radiation at the University Hospital of Tampere, Finland, between 1989 and 1991. The aim of the study was to determine whether there is any advantage or disadvantage if the internal mammary chains (IMC) are included in the radiation target volume. The medial and lateral two-field technique was used and the target volumes were determined randomly either to include the internal mammary chain (IMC-RT) or not (no-IMC-RT). The prevalence of radiation pneumonitis was 16% and there was no significant difference between the IMC- and no-IMC-groups (18 vs. 14%). Skin reactions were equal in both groups. Lung fibrosis was more common in the IMC-RT group.
In conclusion: radiation of internal mammary chain after conservative surgery does not lead to an increase in clinically important skin or pulmonary complications. Whether it prevents recurrences or new primaries of the opposite breast is too early to say because of the short follow-up time.